/* Subroutine */ int ssbevx_(char *jobz, char *range, char *uplo, integer *n,
integer *kd, real *ab, integer *ldab, real *q, integer *ldq, real *vl,
real *vu, integer *il, integer *iu, real *abstol, integer *m, real *
w, real *z__, integer *ldz, real *work, integer *iwork, integer *
ifail, integer *info)
{
/* System generated locals */
integer ab_dim1, ab_offset, q_dim1, q_offset, z_dim1, z_offset, i__1,
i__2;
real r__1, r__2;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
integer i__, j, jj;
real eps, vll, vuu, tmp1;
integer indd, inde;
real anrm;
integer imax;
real rmin, rmax;
logical test;
integer itmp1, indee;
real sigma;
extern logical lsame_(char *, char *);
integer iinfo;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
char order[1];
extern /* Subroutine */ int sgemv_(char *, integer *, integer *, real *,
real *, integer *, real *, integer *, real *, real *, integer *);
logical lower;
extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
integer *), sswap_(integer *, real *, integer *, real *, integer *
);
logical wantz, alleig, indeig;
integer iscale, indibl;
logical valeig;
extern doublereal slamch_(char *);
real safmin;
extern /* Subroutine */ int xerbla_(char *, integer *);
real abstll, bignum;
extern doublereal slansb_(char *, char *, integer *, integer *, real *,
integer *, real *);
extern /* Subroutine */ int slascl_(char *, integer *, integer *, real *,
real *, integer *, integer *, real *, integer *, integer *);
integer indisp, indiwo;
extern /* Subroutine */ int slacpy_(char *, integer *, integer *, real *,
integer *, real *, integer *);
integer indwrk;
extern /* Subroutine */ int ssbtrd_(char *, char *, integer *, integer *,
real *, integer *, real *, real *, real *, integer *, real *,
integer *), sstein_(integer *, real *, real *,
integer *, real *, integer *, integer *, real *, integer *, real *
, integer *, integer *, integer *), ssterf_(integer *, real *,
real *, integer *);
integer nsplit;
real smlnum;
extern /* Subroutine */ int sstebz_(char *, char *, integer *, real *,
real *, integer *, integer *, real *, real *, real *, integer *,
integer *, real *, integer *, integer *, real *, integer *,
integer *), ssteqr_(char *, integer *, real *,
real *, real *, integer *, real *, integer *);
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SSBEVX computes selected eigenvalues and, optionally, eigenvectors */
/* of a real symmetric band matrix A. Eigenvalues and eigenvectors can */
/* be selected by specifying either a range of values or a range of */
/* indices for the desired eigenvalues. */
/* Arguments */
/* ========= */
/* JOBZ (input) CHARACTER*1 */
/* = 'N': Compute eigenvalues only; */
/* = 'V': Compute eigenvalues and eigenvectors. */
/* RANGE (input) CHARACTER*1 */
/* = 'A': all eigenvalues will be found; */
/* = 'V': all eigenvalues in the half-open interval (VL,VU] */
/* will be found; */
/* = 'I': the IL-th through IU-th eigenvalues will be found. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* KD (input) INTEGER */
/* The number of superdiagonals of the matrix A if UPLO = 'U', */
/* or the number of subdiagonals if UPLO = 'L'. KD >= 0. */
/* AB (input/output) REAL array, dimension (LDAB, N) */
/* On entry, the upper or lower triangle of the symmetric band */
/* matrix A, stored in the first KD+1 rows of the array. The */
/* j-th column of A is stored in the j-th column of the array AB */
/* as follows: */
/* if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; */
/* if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). */
/* On exit, AB is overwritten by values generated during the */
/* reduction to tridiagonal form. If UPLO = 'U', the first */
/* superdiagonal and the diagonal of the tridiagonal matrix T */
/* are returned in rows KD and KD+1 of AB, and if UPLO = 'L', */
/* the diagonal and first subdiagonal of T are returned in the */
/* first two rows of AB. */
/* LDAB (input) INTEGER */
/* The leading dimension of the array AB. LDAB >= KD + 1. */
/* Q (output) REAL array, dimension (LDQ, N) */
/* If JOBZ = 'V', the N-by-N orthogonal matrix used in the */
/* reduction to tridiagonal form. */
/* If JOBZ = 'N', the array Q is not referenced. */
/* LDQ (input) INTEGER */
/* The leading dimension of the array Q. If JOBZ = 'V', then */
/* LDQ >= max(1,N). */
/* VL (input) REAL */
/* VU (input) REAL */
/* If RANGE='V', the lower and upper bounds of the interval to */
/* be searched for eigenvalues. VL < VU. */
/* Not referenced if RANGE = 'A' or 'I'. */
/* IL (input) INTEGER */
/* IU (input) INTEGER */
/* If RANGE='I', the indices (in ascending order) of the */
/* smallest and largest eigenvalues to be returned. */
/* 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. */
/* Not referenced if RANGE = 'A' or 'V'. */
/* ABSTOL (input) REAL */
/* The absolute error tolerance for the eigenvalues. */
/* An approximate eigenvalue is accepted as converged */
/* when it is determined to lie in an interval [a,b] */
/* of width less than or equal to */
/* ABSTOL + EPS * max( |a|,|b| ) , */
/* where EPS is the machine precision. If ABSTOL is less than */
/* or equal to zero, then EPS*|T| will be used in its place, */
/* where |T| is the 1-norm of the tridiagonal matrix obtained */
/* by reducing AB to tridiagonal form. */
/* Eigenvalues will be computed most accurately when ABSTOL is */
/* set to twice the underflow threshold 2*SLAMCH('S'), not zero. */
/* If this routine returns with INFO>0, indicating that some */
/* eigenvectors did not converge, try setting ABSTOL to */
/* 2*SLAMCH('S'). */
/* See "Computing Small Singular Values of Bidiagonal Matrices */
/* with Guaranteed High Relative Accuracy," by Demmel and */
/* Kahan, LAPACK Working Note #3. */
/* M (output) INTEGER */
/* The total number of eigenvalues found. 0 <= M <= N. */
/* If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. */
/* W (output) REAL array, dimension (N) */
/* The first M elements contain the selected eigenvalues in */
/* ascending order. */
/* Z (output) REAL array, dimension (LDZ, max(1,M)) */
/* If JOBZ = 'V', then if INFO = 0, the first M columns of Z */
/* contain the orthonormal eigenvectors of the matrix A */
/* corresponding to the selected eigenvalues, with the i-th */
/* column of Z holding the eigenvector associated with W(i). */
/* If an eigenvector fails to converge, then that column of Z */
/* contains the latest approximation to the eigenvector, and the */
/* index of the eigenvector is returned in IFAIL. */
/* If JOBZ = 'N', then Z is not referenced. */
/* Note: the user must ensure that at least max(1,M) columns are */
/* supplied in the array Z; if RANGE = 'V', the exact value of M */
/* is not known in advance and an upper bound must be used. */
/* LDZ (input) INTEGER */
/* The leading dimension of the array Z. LDZ >= 1, and if */
/* JOBZ = 'V', LDZ >= max(1,N). */
/* WORK (workspace) REAL array, dimension (7*N) */
/* IWORK (workspace) INTEGER array, dimension (5*N) */
/* IFAIL (output) INTEGER array, dimension (N) */
/* If JOBZ = 'V', then if INFO = 0, the first M elements of */
/* IFAIL are zero. If INFO > 0, then IFAIL contains the */
/* indices of the eigenvectors that failed to converge. */
/* If JOBZ = 'N', then IFAIL is not referenced. */
/* INFO (output) INTEGER */
/* = 0: successful exit. */
/* < 0: if INFO = -i, the i-th argument had an illegal value. */
/* > 0: if INFO = i, then i eigenvectors failed to converge. */
/* Their indices are stored in array IFAIL. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
ab_dim1 = *ldab;
ab_offset = 1 + ab_dim1;
ab -= ab_offset;
q_dim1 = *ldq;
q_offset = 1 + q_dim1;
q -= q_offset;
--w;
z_dim1 = *ldz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
--work;
--iwork;
--ifail;
/* Function Body */
wantz = lsame_(jobz, "V");
alleig = lsame_(range, "A");
valeig = lsame_(range, "V");
indeig = lsame_(range, "I");
lower = lsame_(uplo, "L");
*info = 0;
if (! (wantz || lsame_(jobz, "N"))) {
*info = -1;
} else if (! (alleig || valeig || indeig)) {
*info = -2;
} else if (! (lower || lsame_(uplo, "U"))) {
*info = -3;
} else if (*n < 0) {
*info = -4;
} else if (*kd < 0) {
*info = -5;
} else if (*ldab < *kd + 1) {
*info = -7;
} else if (wantz && *ldq < max(1,*n)) {
*info = -9;
} else {
if (valeig) {
if (*n > 0 && *vu <= *vl) {
*info = -11;
}
} else if (indeig) {
if (*il < 1 || *il > max(1,*n)) {
*info = -12;
} else if (*iu < min(*n,*il) || *iu > *n) {
*info = -13;
}
}
}
if (*info == 0) {
if (*ldz < 1 || wantz && *ldz < *n) {
*info = -18;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SSBEVX", &i__1);
return 0;
}
/* Quick return if possible */
*m = 0;
if (*n == 0) {
return 0;
}
if (*n == 1) {
*m = 1;
if (lower) {
tmp1 = ab[ab_dim1 + 1];
} else {
tmp1 = ab[*kd + 1 + ab_dim1];
}
if (valeig) {
if (! (*vl < tmp1 && *vu >= tmp1)) {
*m = 0;
}
}
if (*m == 1) {
w[1] = tmp1;
if (wantz) {
z__[z_dim1 + 1] = 1.f;
}
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
/* Computing MIN */
r__1 = sqrt(bignum), r__2 = 1.f / sqrt(sqrt(safmin));
rmax = dmin(r__1,r__2);
/* Scale matrix to allowable range, if necessary. */
iscale = 0;
abstll = *abstol;
if (valeig) {
vll = *vl;
vuu = *vu;
} else {
vll = 0.f;
vuu = 0.f;
}
anrm = slansb_("M", uplo, n, kd, &ab[ab_offset], ldab, &work[1]);
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
if (lower) {
slascl_("B", kd, kd, &c_b14, &sigma, n, n, &ab[ab_offset], ldab,
info);
} else {
slascl_("Q", kd, kd, &c_b14, &sigma, n, n, &ab[ab_offset], ldab,
info);
}
if (*abstol > 0.f) {
abstll = *abstol * sigma;
}
if (valeig) {
vll = *vl * sigma;
vuu = *vu * sigma;
}
}
/* Call SSBTRD to reduce symmetric band matrix to tridiagonal form. */
indd = 1;
inde = indd + *n;
indwrk = inde + *n;
ssbtrd_(jobz, uplo, n, kd, &ab[ab_offset], ldab, &work[indd], &work[inde],
&q[q_offset], ldq, &work[indwrk], &iinfo);
/* If all eigenvalues are desired and ABSTOL is less than or equal */
/* to zero, then call SSTERF or SSTEQR. If this fails for some */
/* eigenvalue, then try SSTEBZ. */
test = FALSE_;
if (indeig) {
if (*il == 1 && *iu == *n) {
test = TRUE_;
}
}
if ((alleig || test) && *abstol <= 0.f) {
scopy_(n, &work[indd], &c__1, &w[1], &c__1);
indee = indwrk + (*n << 1);
if (! wantz) {
i__1 = *n - 1;
scopy_(&i__1, &work[inde], &c__1, &work[indee], &c__1);
ssterf_(n, &w[1], &work[indee], info);
} else {
slacpy_("A", n, n, &q[q_offset], ldq, &z__[z_offset], ldz);
i__1 = *n - 1;
scopy_(&i__1, &work[inde], &c__1, &work[indee], &c__1);
ssteqr_(jobz, n, &w[1], &work[indee], &z__[z_offset], ldz, &work[
indwrk], info);
if (*info == 0) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
ifail[i__] = 0;
/* L10: */
}
}
}
if (*info == 0) {
*m = *n;
goto L30;
}
*info = 0;
}
/* Otherwise, call SSTEBZ and, if eigenvectors are desired, SSTEIN. */
if (wantz) {
*(unsigned char *)order = 'B';
} else {
*(unsigned char *)order = 'E';
}
indibl = 1;
indisp = indibl + *n;
indiwo = indisp + *n;
sstebz_(range, order, n, &vll, &vuu, il, iu, &abstll, &work[indd], &work[
inde], m, &nsplit, &w[1], &iwork[indibl], &iwork[indisp], &work[
indwrk], &iwork[indiwo], info);
if (wantz) {
sstein_(n, &work[indd], &work[inde], m, &w[1], &iwork[indibl], &iwork[
indisp], &z__[z_offset], ldz, &work[indwrk], &iwork[indiwo], &
ifail[1], info);
/* Apply orthogonal matrix used in reduction to tridiagonal */
/* form to eigenvectors returned by SSTEIN. */
i__1 = *m;
for (j = 1; j <= i__1; ++j) {
scopy_(n, &z__[j * z_dim1 + 1], &c__1, &work[1], &c__1);
sgemv_("N", n, n, &c_b14, &q[q_offset], ldq, &work[1], &c__1, &
c_b34, &z__[j * z_dim1 + 1], &c__1);
/* L20: */
}
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
L30:
if (iscale == 1) {
if (*info == 0) {
imax = *m;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
/* If eigenvalues are not in order, then sort them, along with */
/* eigenvectors. */
if (wantz) {
i__1 = *m - 1;
for (j = 1; j <= i__1; ++j) {
i__ = 0;
tmp1 = w[j];
i__2 = *m;
for (jj = j + 1; jj <= i__2; ++jj) {
if (w[jj] < tmp1) {
i__ = jj;
tmp1 = w[jj];
}
/* L40: */
}
if (i__ != 0) {
itmp1 = iwork[indibl + i__ - 1];
w[i__] = w[j];
iwork[indibl + i__ - 1] = iwork[indibl + j - 1];
w[j] = tmp1;
iwork[indibl + j - 1] = itmp1;
sswap_(n, &z__[i__ * z_dim1 + 1], &c__1, &z__[j * z_dim1 + 1],
&c__1);
if (*info != 0) {
itmp1 = ifail[i__];
ifail[i__] = ifail[j];
ifail[j] = itmp1;
}
}
/* L50: */
}
}
return 0;
/* End of SSBEVX */
} /* ssbevx_ */
/* Subroutine */ int spbsvx_(char *fact, char *uplo, integer *n, integer *kd,
integer *nrhs, real *ab, integer *ldab, real *afb, integer *ldafb,
char *equed, real *s, real *b, integer *ldb, real *x, integer *ldx,
real *rcond, real *ferr, real *berr, real *work, integer *iwork,
integer *info)
{
/* System generated locals */
integer ab_dim1, ab_offset, afb_dim1, afb_offset, b_dim1, b_offset,
x_dim1, x_offset, i__1, i__2;
real r__1, r__2;
/* Local variables */
integer i__, j, j1, j2;
real amax, smin, smax;
real scond, anorm;
logical equil, rcequ, upper;
logical nofact;
real bignum;
integer infequ;
real smlnum;
/* -- LAPACK driver routine (version 3.2) -- */
/* November 2006 */
/* Purpose */
/* ======= */
/* SPBSVX uses the Cholesky factorization A = U**T*U or A = L*L**T to */
/* compute the solution to a real system of linear equations */
/* A * X = B, */
/* where A is an N-by-N symmetric positive definite band matrix and X */
/* and B are N-by-NRHS matrices. */
/* Error bounds on the solution and a condition estimate are also */
/* provided. */
/* Description */
/* =========== */
/* The following steps are performed: */
/* 1. If FACT = 'E', real scaling factors are computed to equilibrate */
/* the system: */
/* diag(S) * A * diag(S) * inv(diag(S)) * X = diag(S) * B */
/* Whether or not the system will be equilibrated depends on the */
/* scaling of the matrix A, but if equilibration is used, A is */
/* overwritten by diag(S)*A*diag(S) and B by diag(S)*B. */
/* 2. If FACT = 'N' or 'E', the Cholesky decomposition is used to */
/* factor the matrix A (after equilibration if FACT = 'E') as */
/* A = U**T * U, if UPLO = 'U', or */
/* A = L * L**T, if UPLO = 'L', */
/* where U is an upper triangular band matrix, and L is a lower */
/* triangular band matrix. */
/* 3. If the leading i-by-i principal minor is not positive definite, */
/* then the routine returns with INFO = i. Otherwise, the factored */
/* form of A is used to estimate the condition number of the matrix */
/* A. If the reciprocal of the condition number is less than machine */
/* precision, INFO = N+1 is returned as a warning, but the routine */
/* still goes on to solve for X and compute error bounds as */
/* described below. */
/* 4. The system of equations is solved for X using the factored form */
/* of A. */
/* 5. Iterative refinement is applied to improve the computed solution */
/* matrix and calculate error bounds and backward error estimates */
/* for it. */
/* 6. If equilibration was used, the matrix X is premultiplied by */
/* diag(S) so that it solves the original system before */
/* equilibration. */
/* Arguments */
/* ========= */
/* FACT (input) CHARACTER*1 */
/* Specifies whether or not the factored form of the matrix A is */
/* supplied on entry, and if not, whether the matrix A should be */
/* equilibrated before it is factored. */
/* = 'F': On entry, AFB contains the factored form of A. */
/* If EQUED = 'Y', the matrix A has been equilibrated */
/* with scaling factors given by S. AB and AFB will not */
/* be modified. */
/* = 'N': The matrix A will be copied to AFB and factored. */
/* = 'E': The matrix A will be equilibrated if necessary, then */
/* copied to AFB and factored. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The number of linear equations, i.e., the order of the */
/* matrix A. N >= 0. */
/* KD (input) INTEGER */
/* The number of superdiagonals of the matrix A if UPLO = 'U', */
/* or the number of subdiagonals if UPLO = 'L'. KD >= 0. */
/* NRHS (input) INTEGER */
/* The number of right-hand sides, i.e., the number of columns */
/* of the matrices B and X. NRHS >= 0. */
/* AB (input/output) REAL array, dimension (LDAB,N) */
/* On entry, the upper or lower triangle of the symmetric band */
/* matrix A, stored in the first KD+1 rows of the array, except */
/* if FACT = 'F' and EQUED = 'Y', then A must contain the */
/* equilibrated matrix diag(S)*A*diag(S). The j-th column of A */
/* is stored in the j-th column of the array AB as follows: */
/* if UPLO = 'U', AB(KD+1+i-j,j) = A(i,j) for max(1,j-KD)<=i<=j; */
/* if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(N,j+KD). */
/* See below for further details. */
/* On exit, if FACT = 'E' and EQUED = 'Y', A is overwritten by */
/* diag(S)*A*diag(S). */
/* LDAB (input) INTEGER */
/* The leading dimension of the array A. LDAB >= KD+1. */
/* AFB (input or output) REAL array, dimension (LDAFB,N) */
/* If FACT = 'F', then AFB is an input argument and on entry */
/* contains the triangular factor U or L from the Cholesky */
/* factorization A = U**T*U or A = L*L**T of the band matrix */
/* A, in the same storage format as A (see AB). If EQUED = 'Y', */
/* then AFB is the factored form of the equilibrated matrix A. */
/* If FACT = 'N', then AFB is an output argument and on exit */
/* returns the triangular factor U or L from the Cholesky */
/* factorization A = U**T*U or A = L*L**T. */
/* If FACT = 'E', then AFB is an output argument and on exit */
/* returns the triangular factor U or L from the Cholesky */
/* factorization A = U**T*U or A = L*L**T of the equilibrated */
/* matrix A (see the description of A for the form of the */
/* equilibrated matrix). */
/* LDAFB (input) INTEGER */
/* The leading dimension of the array AFB. LDAFB >= KD+1. */
/* EQUED (input or output) CHARACTER*1 */
/* Specifies the form of equilibration that was done. */
/* = 'N': No equilibration (always true if FACT = 'N'). */
/* = 'Y': Equilibration was done, i.e., A has been replaced by */
/* diag(S) * A * diag(S). */
/* EQUED is an input argument if FACT = 'F'; otherwise, it is an */
/* output argument. */
/* S (input or output) REAL array, dimension (N) */
/* The scale factors for A; not accessed if EQUED = 'N'. S is */
/* an input argument if FACT = 'F'; otherwise, S is an output */
/* argument. If FACT = 'F' and EQUED = 'Y', each element of S */
/* must be positive. */
/* B (input/output) REAL array, dimension (LDB,NRHS) */
/* On entry, the N-by-NRHS right hand side matrix B. */
/* On exit, if EQUED = 'N', B is not modified; if EQUED = 'Y', */
/* B is overwritten by diag(S) * B. */
/* LDB (input) INTEGER */
/* The leading dimension of the array B. LDB >= max(1,N). */
/* X (output) REAL array, dimension (LDX,NRHS) */
/* If INFO = 0 or INFO = N+1, the N-by-NRHS solution matrix X to */
/* the original system of equations. Note that if EQUED = 'Y', */
/* A and B are modified on exit, and the solution to the */
/* equilibrated system is inv(diag(S))*X. */
/* LDX (input) INTEGER */
/* The leading dimension of the array X. LDX >= max(1,N). */
/* RCOND (output) REAL */
/* The estimate of the reciprocal condition number of the matrix */
/* A after equilibration (if done). If RCOND is less than the */
/* machine precision (in particular, if RCOND = 0), the matrix */
/* is singular to working precision. This condition is */
/* indicated by a return code of INFO > 0. */
/* FERR (output) REAL array, dimension (NRHS) */
/* The estimated forward error bound for each solution vector */
/* X(j) (the j-th column of the solution matrix X). */
/* If XTRUE is the true solution corresponding to X(j), FERR(j) */
/* is an estimated upper bound for the magnitude of the largest */
/* element in (X(j) - XTRUE) divided by the magnitude of the */
/* largest element in X(j). The estimate is as reliable as */
/* the estimate for RCOND, and is almost always a slight */
/* overestimate of the true error. */
/* BERR (output) REAL array, dimension (NRHS) */
/* The componentwise relative backward error of each solution */
/* vector X(j) (i.e., the smallest relative change in */
/* any element of A or B that makes X(j) an exact solution). */
/* WORK (workspace) REAL array, dimension (3*N) */
/* IWORK (workspace) INTEGER array, dimension (N) */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* > 0: if INFO = i, and i is */
/* <= N: the leading minor of order i of A is */
/* not positive definite, so the factorization */
/* could not be completed, and the solution has not */
/* been computed. RCOND = 0 is returned. */
/* = N+1: U is nonsingular, but RCOND is less than machine */
/* precision, meaning that the matrix is singular */
/* to working precision. Nevertheless, the */
/* solution and error bounds are computed because */
/* there are a number of situations where the */
/* computed solution can be more accurate than the */
/* value of RCOND would suggest. */
/* Further Details */
/* =============== */
/* The band storage scheme is illustrated by the following example, when */
/* N = 6, KD = 2, and UPLO = 'U': */
/* Two-dimensional storage of the symmetric matrix A: */
/* a11 a12 a13 */
/* a22 a23 a24 */
/* a33 a34 a35 */
/* a44 a45 a46 */
/* a55 a56 */
/* (aij=conjg(aji)) a66 */
/* Band storage of the upper triangle of A: */
/* * * a13 a24 a35 a46 */
/* * a12 a23 a34 a45 a56 */
/* a11 a22 a33 a44 a55 a66 */
/* Similarly, if UPLO = 'L' the format of A is as follows: */
/* a11 a22 a33 a44 a55 a66 */
/* a21 a32 a43 a54 a65 * */
/* a31 a42 a53 a64 * * */
/* Array elements marked * are not used by the routine. */
/* ===================================================================== */
/* Parameter adjustments */
ab_dim1 = *ldab;
ab_offset = 1 + ab_dim1;
ab -= ab_offset;
afb_dim1 = *ldafb;
afb_offset = 1 + afb_dim1;
afb -= afb_offset;
--s;
b_dim1 = *ldb;
b_offset = 1 + b_dim1;
b -= b_offset;
x_dim1 = *ldx;
x_offset = 1 + x_dim1;
x -= x_offset;
--ferr;
--berr;
--work;
--iwork;
/* Function Body */
*info = 0;
nofact = lsame_(fact, "N");
equil = lsame_(fact, "E");
upper = lsame_(uplo, "U");
if (nofact || equil) {
*(unsigned char *)equed = 'N';
rcequ = FALSE_;
} else {
rcequ = lsame_(equed, "Y");
smlnum = slamch_("Safe minimum");
bignum = 1.f / smlnum;
}
/* Test the input parameters. */
if (! nofact && ! equil && ! lsame_(fact, "F")) {
*info = -1;
} else if (! upper && ! lsame_(uplo, "L")) {
*info = -2;
} else if (*n < 0) {
*info = -3;
} else if (*kd < 0) {
*info = -4;
} else if (*nrhs < 0) {
*info = -5;
} else if (*ldab < *kd + 1) {
*info = -7;
} else if (*ldafb < *kd + 1) {
*info = -9;
} else if (lsame_(fact, "F") && ! (rcequ || lsame_(
equed, "N"))) {
*info = -10;
} else {
if (rcequ) {
smin = bignum;
smax = 0.f;
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
/* Computing MIN */
r__1 = smin, r__2 = s[j];
smin = dmin(r__1,r__2);
/* Computing MAX */
r__1 = smax, r__2 = s[j];
smax = dmax(r__1,r__2);
}
if (smin <= 0.f) {
*info = -11;
} else if (*n > 0) {
scond = dmax(smin,smlnum) / dmin(smax,bignum);
} else {
scond = 1.f;
}
}
if (*info == 0) {
if (*ldb < max(1,*n)) {
*info = -13;
} else if (*ldx < max(1,*n)) {
*info = -15;
}
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SPBSVX", &i__1);
return 0;
}
if (equil) {
/* Compute row and column scalings to equilibrate the matrix A. */
spbequ_(uplo, n, kd, &ab[ab_offset], ldab, &s[1], &scond, &amax, &
infequ);
if (infequ == 0) {
/* Equilibrate the matrix. */
slaqsb_(uplo, n, kd, &ab[ab_offset], ldab, &s[1], &scond, &amax,
equed);
rcequ = lsame_(equed, "Y");
}
}
/* Scale the right-hand side. */
if (rcequ) {
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
b[i__ + j * b_dim1] = s[i__] * b[i__ + j * b_dim1];
}
}
}
if (nofact || equil) {
/* Compute the Cholesky factorization A = U'*U or A = L*L'. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
/* Computing MAX */
i__2 = j - *kd;
j1 = max(i__2,1);
i__2 = j - j1 + 1;
scopy_(&i__2, &ab[*kd + 1 - j + j1 + j * ab_dim1], &c__1, &
afb[*kd + 1 - j + j1 + j * afb_dim1], &c__1);
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
/* Computing MIN */
i__2 = j + *kd;
j2 = min(i__2,*n);
i__2 = j2 - j + 1;
scopy_(&i__2, &ab[j * ab_dim1 + 1], &c__1, &afb[j * afb_dim1
+ 1], &c__1);
}
}
spbtrf_(uplo, n, kd, &afb[afb_offset], ldafb, info);
/* Return if INFO is non-zero. */
if (*info > 0) {
*rcond = 0.f;
return 0;
}
}
/* Compute the norm of the matrix A. */
anorm = slansb_("1", uplo, n, kd, &ab[ab_offset], ldab, &work[1]);
/* Compute the reciprocal of the condition number of A. */
spbcon_(uplo, n, kd, &afb[afb_offset], ldafb, &anorm, rcond, &work[1], &
iwork[1], info);
/* Compute the solution matrix X. */
slacpy_("Full", n, nrhs, &b[b_offset], ldb, &x[x_offset], ldx);
spbtrs_(uplo, n, kd, nrhs, &afb[afb_offset], ldafb, &x[x_offset], ldx,
info);
/* Use iterative refinement to improve the computed solution and */
/* compute error bounds and backward error estimates for it. */
spbrfs_(uplo, n, kd, nrhs, &ab[ab_offset], ldab, &afb[afb_offset], ldafb,
&b[b_offset], ldb, &x[x_offset], ldx, &ferr[1], &berr[1], &work[1]
, &iwork[1], info);
/* Transform the solution matrix X to a solution of the original */
/* system. */
if (rcequ) {
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
x[i__ + j * x_dim1] = s[i__] * x[i__ + j * x_dim1];
}
}
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
ferr[j] /= scond;
}
}
/* Set INFO = N+1 if the matrix is singular to working precision. */
if (*rcond < slamch_("Epsilon")) {
*info = *n + 1;
}
return 0;
/* End of SPBSVX */
} /* spbsvx_ */
/* Subroutine */ int spbt02_(char *uplo, integer *n, integer *kd, integer *
nrhs, real *a, integer *lda, real *x, integer *ldx, real *b, integer *
ldb, real *rwork, real *resid)
{
/* System generated locals */
integer a_dim1, a_offset, b_dim1, b_offset, x_dim1, x_offset, i__1;
real r__1, r__2;
/* Local variables */
static integer j;
static real anorm, bnorm;
extern doublereal sasum_(integer *, real *, integer *);
extern /* Subroutine */ int ssbmv_(char *, integer *, integer *, real *,
real *, integer *, real *, integer *, real *, real *, integer *);
static real xnorm;
extern doublereal slamch_(char *), slansb_(char *, char *,
integer *, integer *, real *, integer *, real *);
static real eps;
#define b_ref(a_1,a_2) b[(a_2)*b_dim1 + a_1]
#define x_ref(a_1,a_2) x[(a_2)*x_dim1 + a_1]
/* -- LAPACK test routine (version 3.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
February 29, 1992
Purpose
=======
SPBT02 computes the residual for a solution of a symmetric banded
system of equations A*x = b:
RESID = norm( B - A*X ) / ( norm(A) * norm(X) * EPS)
where EPS is the machine precision.
Arguments
=========
UPLO (input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric matrix A is stored:
= 'U': Upper triangular
= 'L': Lower triangular
N (input) INTEGER
The number of rows and columns of the matrix A. N >= 0.
KD (input) INTEGER
The number of super-diagonals of the matrix A if UPLO = 'U',
or the number of sub-diagonals if UPLO = 'L'. KD >= 0.
A (input) REAL array, dimension (LDA,N)
The original symmetric band matrix A. If UPLO = 'U', the
upper triangular part of A is stored as a band matrix; if
UPLO = 'L', the lower triangular part of A is stored. The
columns of the appropriate triangle are stored in the columns
of A and the diagonals of the triangle are stored in the rows
of A. See SPBTRF for further details.
LDA (input) INTEGER.
The leading dimension of the array A. LDA >= max(1,KD+1).
X (input) REAL array, dimension (LDX,NRHS)
The computed solution vectors for the system of linear
equations.
LDX (input) INTEGER
The leading dimension of the array X. LDX >= max(1,N).
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the right hand side vectors for the system of
linear equations.
On exit, B is overwritten with the difference B - A*X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
RWORK (workspace) REAL array, dimension (N)
RESID (output) REAL
The maximum over the number of right hand sides of
norm(B - A*X) / ( norm(A) * norm(X) * EPS ).
=====================================================================
Quick exit if N = 0 or NRHS = 0.
Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1 * 1;
a -= a_offset;
x_dim1 = *ldx;
x_offset = 1 + x_dim1 * 1;
x -= x_offset;
b_dim1 = *ldb;
b_offset = 1 + b_dim1 * 1;
b -= b_offset;
--rwork;
/* Function Body */
if (*n <= 0 || *nrhs <= 0) {
*resid = 0.f;
return 0;
}
/* Exit with RESID = 1/EPS if ANORM = 0. */
eps = slamch_("Epsilon");
anorm = slansb_("1", uplo, n, kd, &a[a_offset], lda, &rwork[1]);
if (anorm <= 0.f) {
*resid = 1.f / eps;
return 0;
}
/* Compute B - A*X */
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
ssbmv_(uplo, n, kd, &c_b5, &a[a_offset], lda, &x_ref(1, j), &c__1, &
c_b7, &b_ref(1, j), &c__1);
/* L10: */
}
/* Compute the maximum over the number of right hand sides of
norm( B - A*X ) / ( norm(A) * norm(X) * EPS ) */
*resid = 0.f;
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
bnorm = sasum_(n, &b_ref(1, j), &c__1);
xnorm = sasum_(n, &x_ref(1, j), &c__1);
if (xnorm <= 0.f) {
*resid = 1.f / eps;
} else {
/* Computing MAX */
r__1 = *resid, r__2 = bnorm / anorm / xnorm / eps;
*resid = dmax(r__1,r__2);
}
/* L20: */
}
return 0;
/* End of SPBT02 */
} /* spbt02_ */
int ssbev_(char *jobz, char *uplo, int *n, int *kd,
float *ab, int *ldab, float *w, float *z__, int *ldz, float *work,
int *info)
{
/* System generated locals */
int ab_dim1, ab_offset, z_dim1, z_offset, i__1;
float r__1;
/* Builtin functions */
double sqrt(double);
/* Local variables */
float eps;
int inde;
float anrm;
int imax;
float rmin, rmax, sigma;
extern int lsame_(char *, char *);
int iinfo;
extern int sscal_(int *, float *, float *, int *);
int lower, wantz;
int iscale;
extern double slamch_(char *);
float safmin;
extern int xerbla_(char *, int *);
float bignum;
extern double slansb_(char *, char *, int *, int *, float *,
int *, float *);
extern int slascl_(char *, int *, int *, float *,
float *, int *, int *, float *, int *, int *);
int indwrk;
extern int ssbtrd_(char *, char *, int *, int *,
float *, int *, float *, float *, float *, int *, float *,
int *), ssterf_(int *, float *, float *,
int *);
float smlnum;
extern int ssteqr_(char *, int *, float *, float *,
float *, int *, float *, int *);
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SSBEV computes all the eigenvalues and, optionally, eigenvectors of */
/* a float symmetric band matrix A. */
/* Arguments */
/* ========= */
/* JOBZ (input) CHARACTER*1 */
/* = 'N': Compute eigenvalues only; */
/* = 'V': Compute eigenvalues and eigenvectors. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* KD (input) INTEGER */
/* The number of superdiagonals of the matrix A if UPLO = 'U', */
/* or the number of subdiagonals if UPLO = 'L'. KD >= 0. */
/* AB (input/output) REAL array, dimension (LDAB, N) */
/* On entry, the upper or lower triangle of the symmetric band */
/* matrix A, stored in the first KD+1 rows of the array. The */
/* j-th column of A is stored in the j-th column of the array AB */
/* as follows: */
/* if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for MAX(1,j-kd)<=i<=j; */
/* if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=MIN(n,j+kd). */
/* On exit, AB is overwritten by values generated during the */
/* reduction to tridiagonal form. If UPLO = 'U', the first */
/* superdiagonal and the diagonal of the tridiagonal matrix T */
/* are returned in rows KD and KD+1 of AB, and if UPLO = 'L', */
/* the diagonal and first subdiagonal of T are returned in the */
/* first two rows of AB. */
/* LDAB (input) INTEGER */
/* The leading dimension of the array AB. LDAB >= KD + 1. */
/* W (output) REAL array, dimension (N) */
/* If INFO = 0, the eigenvalues in ascending order. */
/* Z (output) REAL array, dimension (LDZ, N) */
/* If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal */
/* eigenvectors of the matrix A, with the i-th column of Z */
/* holding the eigenvector associated with W(i). */
/* If JOBZ = 'N', then Z is not referenced. */
/* LDZ (input) INTEGER */
/* The leading dimension of the array Z. LDZ >= 1, and if */
/* JOBZ = 'V', LDZ >= MAX(1,N). */
/* WORK (workspace) REAL array, dimension (MAX(1,3*N-2)) */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* > 0: if INFO = i, the algorithm failed to converge; i */
/* off-diagonal elements of an intermediate tridiagonal */
/* form did not converge to zero. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
ab_dim1 = *ldab;
ab_offset = 1 + ab_dim1;
ab -= ab_offset;
--w;
z_dim1 = *ldz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
--work;
/* Function Body */
wantz = lsame_(jobz, "V");
lower = lsame_(uplo, "L");
*info = 0;
if (! (wantz || lsame_(jobz, "N"))) {
*info = -1;
} else if (! (lower || lsame_(uplo, "U"))) {
*info = -2;
} else if (*n < 0) {
*info = -3;
} else if (*kd < 0) {
*info = -4;
} else if (*ldab < *kd + 1) {
*info = -6;
} else if (*ldz < 1 || wantz && *ldz < *n) {
*info = -9;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SSBEV ", &i__1);
return 0;
}
/* Quick return if possible */
if (*n == 0) {
return 0;
}
if (*n == 1) {
if (lower) {
w[1] = ab[ab_dim1 + 1];
} else {
w[1] = ab[*kd + 1 + ab_dim1];
}
if (wantz) {
z__[z_dim1 + 1] = 1.f;
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
rmax = sqrt(bignum);
/* Scale matrix to allowable range, if necessary. */
anrm = slansb_("M", uplo, n, kd, &ab[ab_offset], ldab, &work[1]);
iscale = 0;
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
if (lower) {
slascl_("B", kd, kd, &c_b11, &sigma, n, n, &ab[ab_offset], ldab,
info);
} else {
slascl_("Q", kd, kd, &c_b11, &sigma, n, n, &ab[ab_offset], ldab,
info);
}
}
/* Call SSBTRD to reduce symmetric band matrix to tridiagonal form. */
inde = 1;
indwrk = inde + *n;
ssbtrd_(jobz, uplo, n, kd, &ab[ab_offset], ldab, &w[1], &work[inde], &z__[
z_offset], ldz, &work[indwrk], &iinfo);
/* For eigenvalues only, call SSTERF. For eigenvectors, call SSTEQR. */
if (! wantz) {
ssterf_(n, &w[1], &work[inde], info);
} else {
ssteqr_(jobz, n, &w[1], &work[inde], &z__[z_offset], ldz, &work[
indwrk], info);
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
if (iscale == 1) {
if (*info == 0) {
imax = *n;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
return 0;
/* End of SSBEV */
} /* ssbev_ */
/* Subroutine */ int ssbt21_(char *uplo, integer *n, integer *ka, integer *ks,
real *a, integer *lda, real *d__, real *e, real *u, integer *ldu,
real *work, real *result)
{
/* System generated locals */
integer a_dim1, a_offset, u_dim1, u_offset, i__1, i__2, i__3, i__4;
real r__1, r__2;
/* Local variables */
integer j, jc, jr, lw, ika;
real ulp, unfl;
extern /* Subroutine */ int sspr_(char *, integer *, real *, real *,
integer *, real *), sspr2_(char *, integer *, real *,
real *, integer *, real *, integer *, real *);
extern /* Subroutine */ int sgemm_(char *, char *, integer *, integer *,
integer *, real *, real *, integer *, real *, integer *, real *,
real *, integer *);
real anorm;
char cuplo[1];
logical lower;
real wnorm;
extern doublereal slamch_(char *), slange_(char *, integer *,
integer *, real *, integer *, real *), slansb_(char *,
char *, integer *, integer *, real *, integer *, real *), slansp_(char *, char *, integer *, real *, real *);
/* -- LAPACK test routine (version 3.1) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SSBT21 generally checks a decomposition of the form */
/* A = U S U' */
/* where ' means transpose, A is symmetric banded, U is */
/* orthogonal, and S is diagonal (if KS=0) or symmetric */
/* tridiagonal (if KS=1). */
/* Specifically: */
/* RESULT(1) = | A - U S U' | / ( |A| n ulp ) *and* */
/* RESULT(2) = | I - UU' | / ( n ulp ) */
/* Arguments */
/* ========= */
/* UPLO (input) CHARACTER */
/* If UPLO='U', the upper triangle of A and V will be used and */
/* the (strictly) lower triangle will not be referenced. */
/* If UPLO='L', the lower triangle of A and V will be used and */
/* the (strictly) upper triangle will not be referenced. */
/* N (input) INTEGER */
/* The size of the matrix. If it is zero, SSBT21 does nothing. */
/* It must be at least zero. */
/* KA (input) INTEGER */
/* The bandwidth of the matrix A. It must be at least zero. If */
/* it is larger than N-1, then max( 0, N-1 ) will be used. */
/* KS (input) INTEGER */
/* The bandwidth of the matrix S. It may only be zero or one. */
/* If zero, then S is diagonal, and E is not referenced. If */
/* one, then S is symmetric tri-diagonal. */
/* A (input) REAL array, dimension (LDA, N) */
/* The original (unfactored) matrix. It is assumed to be */
/* symmetric, and only the upper (UPLO='U') or only the lower */
/* (UPLO='L') will be referenced. */
/* LDA (input) INTEGER */
/* The leading dimension of A. It must be at least 1 */
/* and at least min( KA, N-1 ). */
/* D (input) REAL array, dimension (N) */
/* The diagonal of the (symmetric tri-) diagonal matrix S. */
/* E (input) REAL array, dimension (N-1) */
/* The off-diagonal of the (symmetric tri-) diagonal matrix S. */
/* E(1) is the (1,2) and (2,1) element, E(2) is the (2,3) and */
/* (3,2) element, etc. */
/* Not referenced if KS=0. */
/* U (input) REAL array, dimension (LDU, N) */
/* The orthogonal matrix in the decomposition, expressed as a */
/* dense matrix (i.e., not as a product of Householder */
/* transformations, Givens transformations, etc.) */
/* LDU (input) INTEGER */
/* The leading dimension of U. LDU must be at least N and */
/* at least 1. */
/* WORK (workspace) REAL array, dimension (N**2+N) */
/* RESULT (output) REAL array, dimension (2) */
/* The values computed by the two tests described above. The */
/* values are currently limited to 1/ulp, to avoid overflow. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Constants */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--d__;
--e;
u_dim1 = *ldu;
u_offset = 1 + u_dim1;
u -= u_offset;
--work;
--result;
/* Function Body */
result[1] = 0.f;
result[2] = 0.f;
if (*n <= 0) {
return 0;
}
/* Computing MAX */
/* Computing MIN */
i__3 = *n - 1;
i__1 = 0, i__2 = min(i__3,*ka);
ika = max(i__1,i__2);
lw = *n * (*n + 1) / 2;
if (lsame_(uplo, "U")) {
lower = FALSE_;
*(unsigned char *)cuplo = 'U';
} else {
lower = TRUE_;
*(unsigned char *)cuplo = 'L';
}
unfl = slamch_("Safe minimum");
ulp = slamch_("Epsilon") * slamch_("Base");
/* Some Error Checks */
/* Do Test 1 */
/* Norm of A: */
/* Computing MAX */
r__1 = slansb_("1", cuplo, n, &ika, &a[a_offset], lda, &work[1]);
anorm = dmax(r__1,unfl);
/* Compute error matrix: Error = A - U S U' */
/* Copy A from SB to SP storage format. */
j = 0;
i__1 = *n;
for (jc = 1; jc <= i__1; ++jc) {
if (lower) {
/* Computing MIN */
i__3 = ika + 1, i__4 = *n + 1 - jc;
i__2 = min(i__3,i__4);
for (jr = 1; jr <= i__2; ++jr) {
++j;
work[j] = a[jr + jc * a_dim1];
/* L10: */
}
i__2 = *n + 1 - jc;
for (jr = ika + 2; jr <= i__2; ++jr) {
++j;
work[j] = 0.f;
/* L20: */
}
} else {
i__2 = jc;
for (jr = ika + 2; jr <= i__2; ++jr) {
++j;
work[j] = 0.f;
/* L30: */
}
/* Computing MIN */
i__2 = ika, i__3 = jc - 1;
for (jr = min(i__2,i__3); jr >= 0; --jr) {
++j;
work[j] = a[ika + 1 - jr + jc * a_dim1];
/* L40: */
}
}
/* L50: */
}
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
r__1 = -d__[j];
sspr_(cuplo, n, &r__1, &u[j * u_dim1 + 1], &c__1, &work[1])
;
/* L60: */
}
if (*n > 1 && *ks == 1) {
i__1 = *n - 1;
for (j = 1; j <= i__1; ++j) {
r__1 = -e[j];
sspr2_(cuplo, n, &r__1, &u[j * u_dim1 + 1], &c__1, &u[(j + 1) *
u_dim1 + 1], &c__1, &work[1]);
/* L70: */
}
}
wnorm = slansp_("1", cuplo, n, &work[1], &work[lw + 1]);
if (anorm > wnorm) {
result[1] = wnorm / anorm / (*n * ulp);
} else {
if (anorm < 1.f) {
/* Computing MIN */
r__1 = wnorm, r__2 = *n * anorm;
result[1] = dmin(r__1,r__2) / anorm / (*n * ulp);
} else {
/* Computing MIN */
r__1 = wnorm / anorm, r__2 = (real) (*n);
result[1] = dmin(r__1,r__2) / (*n * ulp);
}
}
/* Do Test 2 */
/* Compute UU' - I */
sgemm_("N", "C", n, n, n, &c_b22, &u[u_offset], ldu, &u[u_offset], ldu, &
c_b23, &work[1], n);
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
work[(*n + 1) * (j - 1) + 1] += -1.f;
/* L80: */
}
/* Computing MIN */
/* Computing 2nd power */
i__1 = *n;
r__1 = slange_("1", n, n, &work[1], n, &work[i__1 * i__1 + 1]),
r__2 = (real) (*n);
result[2] = dmin(r__1,r__2) / (*n * ulp);
return 0;
/* End of SSBT21 */
} /* ssbt21_ */
/* Subroutine */ int sdrvpb_(logical *dotype, integer *nn, integer *nval,
integer *nrhs, real *thresh, logical *tsterr, integer *nmax, real *a,
real *afac, real *asav, real *b, real *bsav, real *x, real *xact,
real *s, real *work, real *rwork, integer *iwork, integer *nout)
{
/* Initialized data */
static integer iseedy[4] = { 1988,1989,1990,1991 };
static char facts[1*3] = "F" "N" "E";
static char equeds[1*2] = "N" "Y";
/* Format strings */
static char fmt_9999[] = "(1x,a,\002, UPLO='\002,a1,\002', N =\002,i5"
",\002, KD =\002,i5,\002, type \002,i1,\002, test(\002,i1,\002)"
"=\002,g12.5)";
static char fmt_9997[] = "(1x,a,\002( '\002,a1,\002', '\002,a1,\002',"
" \002,i5,\002, \002,i5,\002, ... ), EQUED='\002,a1,\002', type"
" \002,i1,\002, test(\002,i1,\002)=\002,g12.5)";
static char fmt_9998[] = "(1x,a,\002( '\002,a1,\002', '\002,a1,\002',"
" \002,i5,\002, \002,i5,\002, ... ), type \002,i1,\002, test(\002"
",i1,\002)=\002,g12.5)";
/* System generated locals */
address a__1[2];
integer i__1, i__2, i__3, i__4, i__5, i__6, i__7[2];
char ch__1[2];
/* Builtin functions */
/* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen);
integer s_wsfe(cilist *), do_fio(integer *, char *, ftnlen), e_wsfe(void);
/* Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);
/* Local variables */
integer i__, k, n, i1, i2, k1, kd, nb, in, kl, iw, ku, nt, lda, ikd, nkd,
ldab;
char fact[1];
integer ioff, mode, koff;
real amax;
char path[3];
integer imat, info;
char dist[1], uplo[1], type__[1];
integer nrun, ifact, nfail, iseed[4], nfact, kdval[4];
extern logical lsame_(char *, char *);
char equed[1];
integer nbmin;
real rcond, roldc, scond;
integer nimat;
extern doublereal sget06_(real *, real *);
extern /* Subroutine */ int sget04_(integer *, integer *, real *, integer
*, real *, integer *, real *, real *), spbt01_(char *, integer *,
integer *, real *, integer *, real *, integer *, real *, real *);
real anorm;
extern /* Subroutine */ int spbt02_(char *, integer *, integer *, integer
*, real *, integer *, real *, integer *, real *, integer *, real *
, real *), spbt05_(char *, integer *, integer *, integer *
, real *, integer *, real *, integer *, real *, integer *, real *,
integer *, real *, real *, real *);
logical equil;
integer iuplo, izero, nerrs;
extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
integer *), spbsv_(char *, integer *, integer *, integer *, real *
, integer *, real *, integer *, integer *), sswap_(
integer *, real *, integer *, real *, integer *);
logical zerot;
char xtype[1];
extern /* Subroutine */ int slatb4_(char *, integer *, integer *, integer
*, char *, integer *, integer *, real *, integer *, real *, char *
), aladhd_(integer *, char *),
alaerh_(char *, char *, integer *, integer *, char *, integer *,
integer *, integer *, integer *, integer *, integer *, integer *,
integer *, integer *);
logical prefac;
real rcondc;
extern doublereal slange_(char *, integer *, integer *, real *, integer *,
real *);
logical nofact;
char packit[1];
integer iequed;
extern doublereal slansb_(char *, char *, integer *, integer *, real *,
integer *, real *);
real cndnum;
extern /* Subroutine */ int alasvm_(char *, integer *, integer *, integer
*, integer *), slaqsb_(char *, integer *, integer *, real
*, integer *, real *, real *, real *, char *);
real ainvnm;
extern /* Subroutine */ int slacpy_(char *, integer *, integer *, real *,
integer *, real *, integer *), slarhs_(char *, char *,
char *, char *, integer *, integer *, integer *, integer *,
integer *, real *, integer *, real *, integer *, real *, integer *
, integer *, integer *), slaset_(
char *, integer *, integer *, real *, real *, real *, integer *), spbequ_(char *, integer *, integer *, real *, integer *,
real *, real *, real *, integer *), spbtrf_(char *,
integer *, integer *, real *, integer *, integer *),
xlaenv_(integer *, integer *), slatms_(integer *, integer *, char
*, integer *, char *, real *, integer *, real *, real *, integer *
, integer *, char *, real *, integer *, real *, integer *), spbtrs_(char *, integer *, integer *, integer *,
real *, integer *, real *, integer *, integer *);
real result[6];
extern /* Subroutine */ int spbsvx_(char *, char *, integer *, integer *,
integer *, real *, integer *, real *, integer *, char *, real *,
real *, integer *, real *, integer *, real *, real *, real *,
real *, integer *, integer *), serrvx_(
char *, integer *);
/* Fortran I/O blocks */
static cilist io___57 = { 0, 0, 0, fmt_9999, 0 };
static cilist io___60 = { 0, 0, 0, fmt_9997, 0 };
static cilist io___61 = { 0, 0, 0, fmt_9998, 0 };
/* -- LAPACK test routine (version 3.1) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SDRVPB tests the driver routines SPBSV and -SVX. */
/* Arguments */
/* ========= */
/* DOTYPE (input) LOGICAL array, dimension (NTYPES) */
/* The matrix types to be used for testing. Matrices of type j */
/* (for 1 <= j <= NTYPES) are used for testing if DOTYPE(j) = */
/* .TRUE.; if DOTYPE(j) = .FALSE., then type j is not used. */
/* NN (input) INTEGER */
/* The number of values of N contained in the vector NVAL. */
/* NVAL (input) INTEGER array, dimension (NN) */
/* The values of the matrix dimension N. */
/* NRHS (input) INTEGER */
/* The number of right hand side vectors to be generated for */
/* each linear system. */
/* THRESH (input) REAL */
/* The threshold value for the test ratios. A result is */
/* included in the output file if RESULT >= THRESH. To have */
/* every test ratio printed, use THRESH = 0. */
/* TSTERR (input) LOGICAL */
/* Flag that indicates whether error exits are to be tested. */
/* NMAX (input) INTEGER */
/* The maximum value permitted for N, used in dimensioning the */
/* work arrays. */
/* A (workspace) REAL array, dimension (NMAX*NMAX) */
/* AFAC (workspace) REAL array, dimension (NMAX*NMAX) */
/* ASAV (workspace) REAL array, dimension (NMAX*NMAX) */
/* B (workspace) REAL array, dimension (NMAX*NRHS) */
/* BSAV (workspace) REAL array, dimension (NMAX*NRHS) */
/* X (workspace) REAL array, dimension (NMAX*NRHS) */
/* XACT (workspace) REAL array, dimension (NMAX*NRHS) */
/* S (workspace) REAL array, dimension (NMAX) */
/* WORK (workspace) REAL array, dimension */
/* (NMAX*max(3,NRHS)) */
/* RWORK (workspace) REAL array, dimension (NMAX+2*NRHS) */
/* IWORK (workspace) INTEGER array, dimension (NMAX) */
/* NOUT (input) INTEGER */
/* The unit number for output. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. Local Arrays .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Scalars in Common .. */
/* .. */
/* .. Common blocks .. */
/* .. */
/* .. Data statements .. */
/* Parameter adjustments */
--iwork;
--rwork;
--work;
--s;
--xact;
--x;
--bsav;
--b;
--asav;
--afac;
--a;
--nval;
--dotype;
/* Function Body */
/* .. */
/* .. Executable Statements .. */
/* Initialize constants and the random number seed. */
s_copy(path, "Single precision", (ftnlen)1, (ftnlen)16);
s_copy(path + 1, "PB", (ftnlen)2, (ftnlen)2);
nrun = 0;
nfail = 0;
nerrs = 0;
for (i__ = 1; i__ <= 4; ++i__) {
iseed[i__ - 1] = iseedy[i__ - 1];
/* L10: */
}
/* Test the error exits */
if (*tsterr) {
serrvx_(path, nout);
}
infoc_1.infot = 0;
kdval[0] = 0;
/* Set the block size and minimum block size for testing. */
nb = 1;
nbmin = 2;
xlaenv_(&c__1, &nb);
xlaenv_(&c__2, &nbmin);
/* Do for each value of N in NVAL */
i__1 = *nn;
for (in = 1; in <= i__1; ++in) {
n = nval[in];
lda = max(n,1);
*(unsigned char *)xtype = 'N';
/* Set limits on the number of loop iterations. */
/* Computing MAX */
i__2 = 1, i__3 = min(n,4);
nkd = max(i__2,i__3);
nimat = 8;
if (n == 0) {
nimat = 1;
}
kdval[1] = n + (n + 1) / 4;
kdval[2] = (n * 3 - 1) / 4;
kdval[3] = (n + 1) / 4;
i__2 = nkd;
for (ikd = 1; ikd <= i__2; ++ikd) {
/* Do for KD = 0, (5*N+1)/4, (3N-1)/4, and (N+1)/4. This order */
/* makes it easier to skip redundant values for small values */
/* of N. */
kd = kdval[ikd - 1];
ldab = kd + 1;
/* Do first for UPLO = 'U', then for UPLO = 'L' */
for (iuplo = 1; iuplo <= 2; ++iuplo) {
koff = 1;
if (iuplo == 1) {
*(unsigned char *)uplo = 'U';
*(unsigned char *)packit = 'Q';
/* Computing MAX */
i__3 = 1, i__4 = kd + 2 - n;
koff = max(i__3,i__4);
} else {
*(unsigned char *)uplo = 'L';
*(unsigned char *)packit = 'B';
}
i__3 = nimat;
for (imat = 1; imat <= i__3; ++imat) {
/* Do the tests only if DOTYPE( IMAT ) is true. */
if (! dotype[imat]) {
goto L80;
}
/* Skip types 2, 3, or 4 if the matrix size is too small. */
zerot = imat >= 2 && imat <= 4;
if (zerot && n < imat - 1) {
goto L80;
}
if (! zerot || ! dotype[1]) {
/* Set up parameters with SLATB4 and generate a test */
/* matrix with SLATMS. */
slatb4_(path, &imat, &n, &n, type__, &kl, &ku, &anorm,
&mode, &cndnum, dist);
s_copy(srnamc_1.srnamt, "SLATMS", (ftnlen)32, (ftnlen)
6);
slatms_(&n, &n, dist, iseed, type__, &rwork[1], &mode,
&cndnum, &anorm, &kd, &kd, packit, &a[koff],
&ldab, &work[1], &info);
/* Check error code from SLATMS. */
if (info != 0) {
alaerh_(path, "SLATMS", &info, &c__0, uplo, &n, &
n, &c_n1, &c_n1, &c_n1, &imat, &nfail, &
nerrs, nout);
goto L80;
}
} else if (izero > 0) {
/* Use the same matrix for types 3 and 4 as for type */
/* 2 by copying back the zeroed out column, */
iw = (lda << 1) + 1;
if (iuplo == 1) {
ioff = (izero - 1) * ldab + kd + 1;
i__4 = izero - i1;
scopy_(&i__4, &work[iw], &c__1, &a[ioff - izero +
i1], &c__1);
iw = iw + izero - i1;
i__4 = i2 - izero + 1;
/* Computing MAX */
i__6 = ldab - 1;
i__5 = max(i__6,1);
scopy_(&i__4, &work[iw], &c__1, &a[ioff], &i__5);
} else {
ioff = (i1 - 1) * ldab + 1;
i__4 = izero - i1;
/* Computing MAX */
i__6 = ldab - 1;
i__5 = max(i__6,1);
scopy_(&i__4, &work[iw], &c__1, &a[ioff + izero -
i1], &i__5);
ioff = (izero - 1) * ldab + 1;
iw = iw + izero - i1;
i__4 = i2 - izero + 1;
scopy_(&i__4, &work[iw], &c__1, &a[ioff], &c__1);
}
}
/* For types 2-4, zero one row and column of the matrix */
/* to test that INFO is returned correctly. */
izero = 0;
if (zerot) {
if (imat == 2) {
izero = 1;
} else if (imat == 3) {
izero = n;
} else {
izero = n / 2 + 1;
}
/* Save the zeroed out row and column in WORK(*,3) */
iw = lda << 1;
/* Computing MIN */
i__5 = (kd << 1) + 1;
i__4 = min(i__5,n);
for (i__ = 1; i__ <= i__4; ++i__) {
work[iw + i__] = 0.f;
/* L20: */
}
++iw;
/* Computing MAX */
i__4 = izero - kd;
i1 = max(i__4,1);
/* Computing MIN */
i__4 = izero + kd;
i2 = min(i__4,n);
if (iuplo == 1) {
ioff = (izero - 1) * ldab + kd + 1;
i__4 = izero - i1;
sswap_(&i__4, &a[ioff - izero + i1], &c__1, &work[
iw], &c__1);
iw = iw + izero - i1;
i__4 = i2 - izero + 1;
/* Computing MAX */
i__6 = ldab - 1;
i__5 = max(i__6,1);
sswap_(&i__4, &a[ioff], &i__5, &work[iw], &c__1);
} else {
ioff = (i1 - 1) * ldab + 1;
i__4 = izero - i1;
/* Computing MAX */
i__6 = ldab - 1;
i__5 = max(i__6,1);
sswap_(&i__4, &a[ioff + izero - i1], &i__5, &work[
iw], &c__1);
ioff = (izero - 1) * ldab + 1;
iw = iw + izero - i1;
i__4 = i2 - izero + 1;
sswap_(&i__4, &a[ioff], &c__1, &work[iw], &c__1);
}
}
/* Save a copy of the matrix A in ASAV. */
i__4 = kd + 1;
slacpy_("Full", &i__4, &n, &a[1], &ldab, &asav[1], &ldab);
for (iequed = 1; iequed <= 2; ++iequed) {
*(unsigned char *)equed = *(unsigned char *)&equeds[
iequed - 1];
if (iequed == 1) {
nfact = 3;
} else {
nfact = 1;
}
i__4 = nfact;
for (ifact = 1; ifact <= i__4; ++ifact) {
*(unsigned char *)fact = *(unsigned char *)&facts[
ifact - 1];
prefac = lsame_(fact, "F");
nofact = lsame_(fact, "N");
equil = lsame_(fact, "E");
if (zerot) {
if (prefac) {
goto L60;
}
rcondc = 0.f;
} else if (! lsame_(fact, "N")) {
/* Compute the condition number for comparison */
/* with the value returned by SPBSVX (FACT = */
/* 'N' reuses the condition number from the */
/* previous iteration with FACT = 'F'). */
i__5 = kd + 1;
slacpy_("Full", &i__5, &n, &asav[1], &ldab, &
afac[1], &ldab);
if (equil || iequed > 1) {
/* Compute row and column scale factors to */
/* equilibrate the matrix A. */
spbequ_(uplo, &n, &kd, &afac[1], &ldab, &
s[1], &scond, &amax, &info);
if (info == 0 && n > 0) {
if (iequed > 1) {
scond = 0.f;
}
/* Equilibrate the matrix. */
slaqsb_(uplo, &n, &kd, &afac[1], &
ldab, &s[1], &scond, &amax,
equed);
}
}
/* Save the condition number of the */
/* non-equilibrated system for use in SGET04. */
if (equil) {
roldc = rcondc;
}
/* Compute the 1-norm of A. */
anorm = slansb_("1", uplo, &n, &kd, &afac[1],
&ldab, &rwork[1]);
/* Factor the matrix A. */
spbtrf_(uplo, &n, &kd, &afac[1], &ldab, &info);
/* Form the inverse of A. */
slaset_("Full", &n, &n, &c_b45, &c_b46, &a[1],
&lda);
s_copy(srnamc_1.srnamt, "SPBTRS", (ftnlen)32,
(ftnlen)6);
spbtrs_(uplo, &n, &kd, &n, &afac[1], &ldab, &
a[1], &lda, &info);
/* Compute the 1-norm condition number of A. */
ainvnm = slange_("1", &n, &n, &a[1], &lda, &
rwork[1]);
if (anorm <= 0.f || ainvnm <= 0.f) {
rcondc = 1.f;
} else {
rcondc = 1.f / anorm / ainvnm;
}
}
/* Restore the matrix A. */
i__5 = kd + 1;
slacpy_("Full", &i__5, &n, &asav[1], &ldab, &a[1],
&ldab);
/* Form an exact solution and set the right hand */
/* side. */
s_copy(srnamc_1.srnamt, "SLARHS", (ftnlen)32, (
ftnlen)6);
slarhs_(path, xtype, uplo, " ", &n, &n, &kd, &kd,
nrhs, &a[1], &ldab, &xact[1], &lda, &b[1],
&lda, iseed, &info);
*(unsigned char *)xtype = 'C';
slacpy_("Full", &n, nrhs, &b[1], &lda, &bsav[1], &
lda);
if (nofact) {
/* --- Test SPBSV --- */
/* Compute the L*L' or U'*U factorization of the */
/* matrix and solve the system. */
i__5 = kd + 1;
slacpy_("Full", &i__5, &n, &a[1], &ldab, &
afac[1], &ldab);
slacpy_("Full", &n, nrhs, &b[1], &lda, &x[1],
&lda);
s_copy(srnamc_1.srnamt, "SPBSV ", (ftnlen)32,
(ftnlen)6);
spbsv_(uplo, &n, &kd, nrhs, &afac[1], &ldab, &
x[1], &lda, &info);
/* Check error code from SPBSV . */
if (info != izero) {
alaerh_(path, "SPBSV ", &info, &izero,
uplo, &n, &n, &kd, &kd, nrhs, &
imat, &nfail, &nerrs, nout);
goto L40;
} else if (info != 0) {
goto L40;
}
/* Reconstruct matrix from factors and compute */
/* residual. */
spbt01_(uplo, &n, &kd, &a[1], &ldab, &afac[1],
&ldab, &rwork[1], result);
/* Compute residual of the computed solution. */
slacpy_("Full", &n, nrhs, &b[1], &lda, &work[
1], &lda);
spbt02_(uplo, &n, &kd, nrhs, &a[1], &ldab, &x[
1], &lda, &work[1], &lda, &rwork[1], &
result[1]);
/* Check solution from generated exact solution. */
sget04_(&n, nrhs, &x[1], &lda, &xact[1], &lda,
&rcondc, &result[2]);
nt = 3;
/* Print information about the tests that did */
/* not pass the threshold. */
i__5 = nt;
for (k = 1; k <= i__5; ++k) {
if (result[k - 1] >= *thresh) {
if (nfail == 0 && nerrs == 0) {
aladhd_(nout, path);
}
io___57.ciunit = *nout;
s_wsfe(&io___57);
do_fio(&c__1, "SPBSV ", (ftnlen)6);
do_fio(&c__1, uplo, (ftnlen)1);
do_fio(&c__1, (char *)&n, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&kd, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&imat, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&k, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&result[k - 1],
(ftnlen)sizeof(real));
e_wsfe();
++nfail;
}
/* L30: */
}
nrun += nt;
L40:
;
}
/* --- Test SPBSVX --- */
if (! prefac) {
i__5 = kd + 1;
slaset_("Full", &i__5, &n, &c_b45, &c_b45, &
afac[1], &ldab);
}
slaset_("Full", &n, nrhs, &c_b45, &c_b45, &x[1], &
lda);
if (iequed > 1 && n > 0) {
/* Equilibrate the matrix if FACT='F' and */
/* EQUED='Y' */
slaqsb_(uplo, &n, &kd, &a[1], &ldab, &s[1], &
scond, &amax, equed);
}
/* Solve the system and compute the condition */
/* number and error bounds using SPBSVX. */
s_copy(srnamc_1.srnamt, "SPBSVX", (ftnlen)32, (
ftnlen)6);
spbsvx_(fact, uplo, &n, &kd, nrhs, &a[1], &ldab, &
afac[1], &ldab, equed, &s[1], &b[1], &lda,
&x[1], &lda, &rcond, &rwork[1], &rwork[*
nrhs + 1], &work[1], &iwork[1], &info);
/* Check the error code from SPBSVX. */
if (info != izero) {
/* Writing concatenation */
i__7[0] = 1, a__1[0] = fact;
i__7[1] = 1, a__1[1] = uplo;
s_cat(ch__1, a__1, i__7, &c__2, (ftnlen)2);
alaerh_(path, "SPBSVX", &info, &izero, ch__1,
&n, &n, &kd, &kd, nrhs, &imat, &nfail,
&nerrs, nout);
goto L60;
}
if (info == 0) {
if (! prefac) {
/* Reconstruct matrix from factors and */
/* compute residual. */
spbt01_(uplo, &n, &kd, &a[1], &ldab, &
afac[1], &ldab, &rwork[(*nrhs <<
1) + 1], result);
k1 = 1;
} else {
k1 = 2;
}
/* Compute residual of the computed solution. */
slacpy_("Full", &n, nrhs, &bsav[1], &lda, &
work[1], &lda);
spbt02_(uplo, &n, &kd, nrhs, &asav[1], &ldab,
&x[1], &lda, &work[1], &lda, &rwork[(*
nrhs << 1) + 1], &result[1]);
/* Check solution from generated exact solution. */
if (nofact || prefac && lsame_(equed, "N")) {
sget04_(&n, nrhs, &x[1], &lda, &xact[1], &
lda, &rcondc, &result[2]);
} else {
sget04_(&n, nrhs, &x[1], &lda, &xact[1], &
lda, &roldc, &result[2]);
}
/* Check the error bounds from iterative */
/* refinement. */
spbt05_(uplo, &n, &kd, nrhs, &asav[1], &ldab,
&b[1], &lda, &x[1], &lda, &xact[1], &
lda, &rwork[1], &rwork[*nrhs + 1], &
result[3]);
} else {
k1 = 6;
}
/* Compare RCOND from SPBSVX with the computed */
/* value in RCONDC. */
result[5] = sget06_(&rcond, &rcondc);
/* Print information about the tests that did not */
/* pass the threshold. */
for (k = k1; k <= 6; ++k) {
if (result[k - 1] >= *thresh) {
if (nfail == 0 && nerrs == 0) {
aladhd_(nout, path);
}
if (prefac) {
io___60.ciunit = *nout;
s_wsfe(&io___60);
do_fio(&c__1, "SPBSVX", (ftnlen)6);
do_fio(&c__1, fact, (ftnlen)1);
do_fio(&c__1, uplo, (ftnlen)1);
do_fio(&c__1, (char *)&n, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&kd, (ftnlen)
sizeof(integer));
do_fio(&c__1, equed, (ftnlen)1);
do_fio(&c__1, (char *)&imat, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&k, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&result[k - 1],
(ftnlen)sizeof(real));
e_wsfe();
} else {
io___61.ciunit = *nout;
s_wsfe(&io___61);
do_fio(&c__1, "SPBSVX", (ftnlen)6);
do_fio(&c__1, fact, (ftnlen)1);
do_fio(&c__1, uplo, (ftnlen)1);
do_fio(&c__1, (char *)&n, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&kd, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&imat, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&k, (ftnlen)
sizeof(integer));
do_fio(&c__1, (char *)&result[k - 1],
(ftnlen)sizeof(real));
e_wsfe();
}
++nfail;
}
/* L50: */
}
nrun = nrun + 7 - k1;
L60:
;
}
/* L70: */
}
L80:
;
}
/* L90: */
}
/* L100: */
}
/* L110: */
}
/* Print a summary of the results. */
alasvm_(path, nout, &nfail, &nrun, &nerrs);
return 0;
/* End of SDRVPB */
} /* sdrvpb_ */
/* Subroutine */ int spbt01_(char *uplo, integer *n, integer *kd, real *a,
integer *lda, real *afac, integer *ldafac, real *rwork, real *resid)
{
/* System generated locals */
integer a_dim1, a_offset, afac_dim1, afac_offset, i__1, i__2, i__3;
/* Local variables */
integer i__, j, k;
real t;
integer kc, ml, mu;
real eps;
integer klen;
extern doublereal sdot_(integer *, real *, integer *, real *, integer *);
extern /* Subroutine */ int ssyr_(char *, integer *, real *, real *,
integer *, real *, integer *);
extern logical lsame_(char *, char *);
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
real anorm;
extern /* Subroutine */ int strmv_(char *, char *, char *, integer *,
real *, integer *, real *, integer *);
extern doublereal slamch_(char *), slansb_(char *, char *,
integer *, integer *, real *, integer *, real *);
/* -- LAPACK test routine (version 3.1) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SPBT01 reconstructs a symmetric positive definite band matrix A from */
/* its L*L' or U'*U factorization and computes the residual */
/* norm( L*L' - A ) / ( N * norm(A) * EPS ) or */
/* norm( U'*U - A ) / ( N * norm(A) * EPS ), */
/* where EPS is the machine epsilon, L' is the conjugate transpose of */
/* L, and U' is the conjugate transpose of U. */
/* Arguments */
/* ========= */
/* UPLO (input) CHARACTER*1 */
/* Specifies whether the upper or lower triangular part of the */
/* symmetric matrix A is stored: */
/* = 'U': Upper triangular */
/* = 'L': Lower triangular */
/* N (input) INTEGER */
/* The number of rows and columns of the matrix A. N >= 0. */
/* KD (input) INTEGER */
/* The number of super-diagonals of the matrix A if UPLO = 'U', */
/* or the number of sub-diagonals if UPLO = 'L'. KD >= 0. */
/* A (input) REAL array, dimension (LDA,N) */
/* The original symmetric band matrix A. If UPLO = 'U', the */
/* upper triangular part of A is stored as a band matrix; if */
/* UPLO = 'L', the lower triangular part of A is stored. The */
/* columns of the appropriate triangle are stored in the columns */
/* of A and the diagonals of the triangle are stored in the rows */
/* of A. See SPBTRF for further details. */
/* LDA (input) INTEGER. */
/* The leading dimension of the array A. LDA >= max(1,KD+1). */
/* AFAC (input) REAL array, dimension (LDAFAC,N) */
/* The factored form of the matrix A. AFAC contains the factor */
/* L or U from the L*L' or U'*U factorization in band storage */
/* format, as computed by SPBTRF. */
/* LDAFAC (input) INTEGER */
/* The leading dimension of the array AFAC. */
/* LDAFAC >= max(1,KD+1). */
/* RWORK (workspace) REAL array, dimension (N) */
/* RESID (output) REAL */
/* If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS ) */
/* If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS ) */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Quick exit if N = 0. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
afac_dim1 = *ldafac;
afac_offset = 1 + afac_dim1;
afac -= afac_offset;
--rwork;
/* Function Body */
if (*n <= 0) {
*resid = 0.f;
return 0;
}
/* Exit with RESID = 1/EPS if ANORM = 0. */
eps = slamch_("Epsilon");
anorm = slansb_("1", uplo, n, kd, &a[a_offset], lda, &rwork[1]);
if (anorm <= 0.f) {
*resid = 1.f / eps;
return 0;
}
/* Compute the product U'*U, overwriting U. */
if (lsame_(uplo, "U")) {
for (k = *n; k >= 1; --k) {
/* Computing MAX */
i__1 = 1, i__2 = *kd + 2 - k;
kc = max(i__1,i__2);
klen = *kd + 1 - kc;
/* Compute the (K,K) element of the result. */
i__1 = klen + 1;
t = sdot_(&i__1, &afac[kc + k * afac_dim1], &c__1, &afac[kc + k *
afac_dim1], &c__1);
afac[*kd + 1 + k * afac_dim1] = t;
/* Compute the rest of column K. */
if (klen > 0) {
i__1 = *ldafac - 1;
strmv_("Upper", "Transpose", "Non-unit", &klen, &afac[*kd + 1
+ (k - klen) * afac_dim1], &i__1, &afac[kc + k *
afac_dim1], &c__1);
}
/* L10: */
}
/* UPLO = 'L': Compute the product L*L', overwriting L. */
} else {
for (k = *n; k >= 1; --k) {
/* Computing MIN */
i__1 = *kd, i__2 = *n - k;
klen = min(i__1,i__2);
/* Add a multiple of column K of the factor L to each of */
/* columns K+1 through N. */
if (klen > 0) {
i__1 = *ldafac - 1;
ssyr_("Lower", &klen, &c_b14, &afac[k * afac_dim1 + 2], &c__1,
&afac[(k + 1) * afac_dim1 + 1], &i__1);
}
/* Scale column K by the diagonal element. */
t = afac[k * afac_dim1 + 1];
i__1 = klen + 1;
sscal_(&i__1, &t, &afac[k * afac_dim1 + 1], &c__1);
/* L20: */
}
}
/* Compute the difference L*L' - A or U'*U - A. */
if (lsame_(uplo, "U")) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
/* Computing MAX */
i__2 = 1, i__3 = *kd + 2 - j;
mu = max(i__2,i__3);
i__2 = *kd + 1;
for (i__ = mu; i__ <= i__2; ++i__) {
afac[i__ + j * afac_dim1] -= a[i__ + j * a_dim1];
/* L30: */
}
/* L40: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
/* Computing MIN */
i__2 = *kd + 1, i__3 = *n - j + 1;
ml = min(i__2,i__3);
i__2 = ml;
for (i__ = 1; i__ <= i__2; ++i__) {
afac[i__ + j * afac_dim1] -= a[i__ + j * a_dim1];
/* L50: */
}
/* L60: */
}
}
/* Compute norm( L*L' - A ) / ( N * norm(A) * EPS ) */
*resid = slansb_("I", uplo, n, kd, &afac[afac_offset], ldafac, &rwork[1]);
*resid = *resid / (real) (*n) / anorm / eps;
return 0;
/* End of SPBT01 */
} /* spbt01_ */
/* Subroutine */ int ssbevx_(char *jobz, char *range, char *uplo, integer *n,
integer *kd, real *ab, integer *ldab, real *q, integer *ldq, real *vl,
real *vu, integer *il, integer *iu, real *abstol, integer *m, real *
w, real *z, integer *ldz, real *work, integer *iwork, integer *ifail,
integer *info)
{
/* -- LAPACK driver routine (version 2.0) --
Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
Courant Institute, Argonne National Lab, and Rice University
September 30, 1994
Purpose
=======
SSBEVX computes selected eigenvalues and, optionally, eigenvectors
of a real symmetric band matrix A. Eigenvalues and eigenvectors can
be selected by specifying either a range of values or a range of
indices for the desired eigenvalues.
Arguments
=========
JOBZ (input) CHARACTER*1
= 'N': Compute eigenvalues only;
= 'V': Compute eigenvalues and eigenvectors.
RANGE (input) CHARACTER*1
= 'A': all eigenvalues will be found;
= 'V': all eigenvalues in the half-open interval (VL,VU]
will be found;
= 'I': the IL-th through IU-th eigenvalues will be found.
UPLO (input) CHARACTER*1
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N (input) INTEGER
The order of the matrix A. N >= 0.
KD (input) INTEGER
The number of superdiagonals of the matrix A if UPLO = 'U',
or the number of subdiagonals if UPLO = 'L'. KD >= 0.
AB (input/output) REAL array, dimension (LDAB, N)
On entry, the upper or lower triangle of the symmetric band
matrix A, stored in the first KD+1 rows of the array. The
j-th column of A is stored in the j-th column of the array AB
as follows:
if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j;
if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd).
On exit, AB is overwritten by values generated during the
reduction to tridiagonal form. If UPLO = 'U', the first
superdiagonal and the diagonal of the tridiagonal matrix T
are returned in rows KD and KD+1 of AB, and if UPLO = 'L',
the diagonal and first subdiagonal of T are returned in the
first two rows of AB.
LDAB (input) INTEGER
The leading dimension of the array AB. LDAB >= KD + 1.
Q (output) REAL array, dimension (LDQ, N)
If JOBZ = 'V', the N-by-N orthogonal matrix used in the
reduction to tridiagonal form.
If JOBZ = 'N', the array Q is not referenced.
LDQ (input) INTEGER
The leading dimension of the array Q. If JOBZ = 'V', then
LDQ >= max(1,N).
VL (input) REAL
VU (input) REAL
If RANGE='V', the lower and upper bounds of the interval to
be searched for eigenvalues. VL < VU.
Not referenced if RANGE = 'A' or 'I'.
IL (input) INTEGER
IU (input) INTEGER
If RANGE='I', the indices (in ascending order) of the
smallest and largest eigenvalues to be returned.
1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0.
Not referenced if RANGE = 'A' or 'V'.
ABSTOL (input) REAL
The absolute error tolerance for the eigenvalues.
An approximate eigenvalue is accepted as converged
when it is determined to lie in an interval [a,b]
of width less than or equal to
ABSTOL + EPS * max( |a|,|b| ) ,
where EPS is the machine precision. If ABSTOL is less than
or equal to zero, then EPS*|T| will be used in its place,
where |T| is the 1-norm of the tridiagonal matrix obtained
by reducing AB to tridiagonal form.
Eigenvalues will be computed most accurately when ABSTOL is
set to twice the underflow threshold 2*SLAMCH('S'), not zero.
If this routine returns with INFO>0, indicating that some
eigenvectors did not converge, try setting ABSTOL to
2*SLAMCH('S').
See "Computing Small Singular Values of Bidiagonal Matrices
with Guaranteed High Relative Accuracy," by Demmel and
Kahan, LAPACK Working Note #3.
M (output) INTEGER
The total number of eigenvalues found. 0 <= M <= N.
If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.
W (output) REAL array, dimension (N)
The first M elements contain the selected eigenvalues in
ascending order.
Z (output) REAL array, dimension (LDZ, max(1,M))
If JOBZ = 'V', then if INFO = 0, the first M columns of Z
contain the orthonormal eigenvectors of the matrix A
corresponding to the selected eigenvalues, with the i-th
column of Z holding the eigenvector associated with W(i).
If an eigenvector fails to converge, then that column of Z
contains the latest approximation to the eigenvector, and the
index of the eigenvector is returned in IFAIL.
If JOBZ = 'N', then Z is not referenced.
Note: the user must ensure that at least max(1,M) columns are
supplied in the array Z; if RANGE = 'V', the exact value of M
is not known in advance and an upper bound must be used.
LDZ (input) INTEGER
The leading dimension of the array Z. LDZ >= 1, and if
JOBZ = 'V', LDZ >= max(1,N).
WORK (workspace) REAL array, dimension (7*N)
IWORK (workspace) INTEGER array, dimension (5*N)
IFAIL (output) INTEGER array, dimension (N)
If JOBZ = 'V', then if INFO = 0, the first M elements of
IFAIL are zero. If INFO > 0, then IFAIL contains the
indices of the eigenvectors that failed to converge.
If JOBZ = 'N', then IFAIL is not referenced.
INFO (output) INTEGER
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
> 0: if INFO = i, then i eigenvectors failed to converge.
Their indices are stored in array IFAIL.
=====================================================================
Test the input parameters.
Parameter adjustments
Function Body */
/* Table of constant values */
static real c_b14 = 1.f;
static integer c__1 = 1;
static real c_b34 = 0.f;
/* System generated locals */
integer ab_dim1, ab_offset, q_dim1, q_offset, z_dim1, z_offset, i__1,
i__2;
real r__1, r__2;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
static integer indd, inde;
static real anrm;
static integer imax;
static real rmin, rmax;
static integer itmp1, i, j, indee;
static real sigma;
extern logical lsame_(char *, char *);
static integer iinfo;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
static char order[1];
extern /* Subroutine */ int sgemv_(char *, integer *, integer *, real *,
real *, integer *, real *, integer *, real *, real *, integer *);
static logical lower;
extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
integer *), sswap_(integer *, real *, integer *, real *, integer *
);
static logical wantz;
static integer jj;
static logical alleig, indeig;
static integer iscale, indibl;
static logical valeig;
extern doublereal slamch_(char *);
static real safmin;
extern /* Subroutine */ int xerbla_(char *, integer *);
static real abstll, bignum;
extern doublereal slansb_(char *, char *, integer *, integer *, real *,
integer *, real *);
extern /* Subroutine */ int slascl_(char *, integer *, integer *, real *,
real *, integer *, integer *, real *, integer *, integer *);
static integer indisp, indiwo;
extern /* Subroutine */ int slacpy_(char *, integer *, integer *, real *,
integer *, real *, integer *);
static integer indwrk;
extern /* Subroutine */ int ssbtrd_(char *, char *, integer *, integer *,
real *, integer *, real *, real *, real *, integer *, real *,
integer *), sstein_(integer *, real *, real *,
integer *, real *, integer *, integer *, real *, integer *, real *
, integer *, integer *, integer *), ssterf_(integer *, real *,
real *, integer *);
static integer nsplit;
static real smlnum;
extern /* Subroutine */ int sstebz_(char *, char *, integer *, real *,
real *, integer *, integer *, real *, real *, real *, integer *,
integer *, real *, integer *, integer *, real *, integer *,
integer *), ssteqr_(char *, integer *, real *,
real *, real *, integer *, real *, integer *);
static real eps, vll, vuu, tmp1;
#define W(I) w[(I)-1]
#define WORK(I) work[(I)-1]
#define IWORK(I) iwork[(I)-1]
#define IFAIL(I) ifail[(I)-1]
#define AB(I,J) ab[(I)-1 + ((J)-1)* ( *ldab)]
#define Q(I,J) q[(I)-1 + ((J)-1)* ( *ldq)]
#define Z(I,J) z[(I)-1 + ((J)-1)* ( *ldz)]
wantz = lsame_(jobz, "V");
alleig = lsame_(range, "A");
valeig = lsame_(range, "V");
indeig = lsame_(range, "I");
lower = lsame_(uplo, "L");
*info = 0;
if (! (wantz || lsame_(jobz, "N"))) {
*info = -1;
} else if (! (alleig || valeig || indeig)) {
*info = -2;
} else if (! (lower || lsame_(uplo, "U"))) {
*info = -3;
} else if (*n < 0) {
*info = -4;
} else if (*kd < 0) {
*info = -5;
} else if (*ldab < *kd + 1) {
*info = -7;
} else if (*ldq < *n) {
*info = -9;
} else if (valeig && *n > 0 && *vu <= *vl) {
*info = -11;
} else if (indeig && *il < 1) {
*info = -12;
} else if (indeig && (*iu < min(*n,*il) || *iu > *n)) {
*info = -13;
} else if (*ldz < 1 || wantz && *ldz < *n) {
*info = -18;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("SSBEVX", &i__1);
return 0;
}
/* Quick return if possible */
*m = 0;
if (*n == 0) {
return 0;
}
if (*n == 1) {
if (alleig || indeig) {
*m = 1;
W(1) = AB(1,1);
} else {
if (*vl < AB(1,1) && *vu >= AB(1,1)) {
*m = 1;
W(1) = AB(1,1);
}
}
if (wantz) {
Z(1,1) = 1.f;
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
/* Computing MIN */
r__1 = sqrt(bignum), r__2 = 1.f / sqrt(sqrt(safmin));
rmax = dmin(r__1,r__2);
/* Scale matrix to allowable range, if necessary. */
iscale = 0;
abstll = *abstol;
if (valeig) {
vll = *vl;
vuu = *vu;
}
anrm = slansb_("M", uplo, n, kd, &AB(1,1), ldab, &WORK(1));
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
if (lower) {
slascl_("B", kd, kd, &c_b14, &sigma, n, n, &AB(1,1), ldab,
info);
} else {
slascl_("Q", kd, kd, &c_b14, &sigma, n, n, &AB(1,1), ldab,
info);
}
if (*abstol > 0.f) {
abstll = *abstol * sigma;
}
if (valeig) {
vll = *vl * sigma;
vuu = *vu * sigma;
}
}
/* Call SSBTRD to reduce symmetric band matrix to tridiagonal form. */
indd = 1;
inde = indd + *n;
indwrk = inde + *n;
ssbtrd_(jobz, uplo, n, kd, &AB(1,1), ldab, &WORK(indd), &WORK(inde),
&Q(1,1), ldq, &WORK(indwrk), &iinfo);
/* If all eigenvalues are desired and ABSTOL is less than or equal
to zero, then call SSTERF or SSTEQR. If this fails for some
eigenvalue, then try SSTEBZ. */
if ((alleig || indeig && *il == 1 && *iu == *n) && *abstol <= 0.f) {
scopy_(n, &WORK(indd), &c__1, &W(1), &c__1);
indee = indwrk + (*n << 1);
if (! wantz) {
i__1 = *n - 1;
scopy_(&i__1, &WORK(inde), &c__1, &WORK(indee), &c__1);
ssterf_(n, &W(1), &WORK(indee), info);
} else {
slacpy_("A", n, n, &Q(1,1), ldq, &Z(1,1), ldz);
i__1 = *n - 1;
scopy_(&i__1, &WORK(inde), &c__1, &WORK(indee), &c__1);
ssteqr_(jobz, n, &W(1), &WORK(indee), &Z(1,1), ldz, &WORK(
indwrk), info);
if (*info == 0) {
i__1 = *n;
for (i = 1; i <= *n; ++i) {
IFAIL(i) = 0;
/* L10: */
}
}
}
if (*info == 0) {
*m = *n;
goto L30;
}
*info = 0;
}
/* Otherwise, call SSTEBZ and, if eigenvectors are desired, SSTEIN. */
if (wantz) {
*(unsigned char *)order = 'B';
} else {
*(unsigned char *)order = 'E';
}
indibl = 1;
indisp = indibl + *n;
indiwo = indisp + *n;
sstebz_(range, order, n, &vll, &vuu, il, iu, &abstll, &WORK(indd), &WORK(
inde), m, &nsplit, &W(1), &IWORK(indibl), &IWORK(indisp), &WORK(
indwrk), &IWORK(indiwo), info);
if (wantz) {
sstein_(n, &WORK(indd), &WORK(inde), m, &W(1), &IWORK(indibl), &IWORK(
indisp), &Z(1,1), ldz, &WORK(indwrk), &IWORK(indiwo), &
IFAIL(1), info);
/* Apply orthogonal matrix used in reduction to tridiagonal
form to eigenvectors returned by SSTEIN. */
i__1 = *m;
for (j = 1; j <= *m; ++j) {
scopy_(n, &Z(1,j), &c__1, &WORK(1), &c__1);
sgemv_("N", n, n, &c_b14, &Q(1,1), ldq, &WORK(1), &c__1, &
c_b34, &Z(1,j), &c__1);
/* L20: */
}
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
L30:
if (iscale == 1) {
if (*info == 0) {
imax = *m;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &W(1), &c__1);
}
/* If eigenvalues are not in order, then sort them, along with
eigenvectors. */
if (wantz) {
i__1 = *m - 1;
for (j = 1; j <= *m-1; ++j) {
i = 0;
tmp1 = W(j);
i__2 = *m;
for (jj = j + 1; jj <= *m; ++jj) {
if (W(jj) < tmp1) {
i = jj;
tmp1 = W(jj);
}
/* L40: */
}
if (i != 0) {
itmp1 = IWORK(indibl + i - 1);
W(i) = W(j);
IWORK(indibl + i - 1) = IWORK(indibl + j - 1);
W(j) = tmp1;
IWORK(indibl + j - 1) = itmp1;
sswap_(n, &Z(1,i), &c__1, &Z(1,j), &
c__1);
if (*info != 0) {
itmp1 = IFAIL(i);
IFAIL(i) = IFAIL(j);
IFAIL(j) = itmp1;
}
}
/* L50: */
}
}
return 0;
/* End of SSBEVX */
} /* ssbevx_ */
/* Subroutine */ int spbt02_(char *uplo, integer *n, integer *kd, integer *
nrhs, real *a, integer *lda, real *x, integer *ldx, real *b, integer *
ldb, real *rwork, real *resid)
{
/* System generated locals */
integer a_dim1, a_offset, b_dim1, b_offset, x_dim1, x_offset, i__1;
real r__1, r__2;
/* Local variables */
integer j;
real eps, anorm, bnorm;
real xnorm;
/* -- LAPACK test routine (version 3.1) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SPBT02 computes the residual for a solution of a symmetric banded */
/* system of equations A*x = b: */
/* RESID = norm( B - A*X ) / ( norm(A) * norm(X) * EPS) */
/* where EPS is the machine precision. */
/* Arguments */
/* ========= */
/* UPLO (input) CHARACTER*1 */
/* Specifies whether the upper or lower triangular part of the */
/* symmetric matrix A is stored: */
/* = 'U': Upper triangular */
/* = 'L': Lower triangular */
/* N (input) INTEGER */
/* The number of rows and columns of the matrix A. N >= 0. */
/* KD (input) INTEGER */
/* The number of super-diagonals of the matrix A if UPLO = 'U', */
/* or the number of sub-diagonals if UPLO = 'L'. KD >= 0. */
/* A (input) REAL array, dimension (LDA,N) */
/* The original symmetric band matrix A. If UPLO = 'U', the */
/* upper triangular part of A is stored as a band matrix; if */
/* UPLO = 'L', the lower triangular part of A is stored. The */
/* columns of the appropriate triangle are stored in the columns */
/* of A and the diagonals of the triangle are stored in the rows */
/* of A. See SPBTRF for further details. */
/* LDA (input) INTEGER. */
/* The leading dimension of the array A. LDA >= max(1,KD+1). */
/* X (input) REAL array, dimension (LDX,NRHS) */
/* The computed solution vectors for the system of linear */
/* equations. */
/* LDX (input) INTEGER */
/* The leading dimension of the array X. LDX >= max(1,N). */
/* B (input/output) REAL array, dimension (LDB,NRHS) */
/* On entry, the right hand side vectors for the system of */
/* linear equations. */
/* On exit, B is overwritten with the difference B - A*X. */
/* LDB (input) INTEGER */
/* The leading dimension of the array B. LDB >= max(1,N). */
/* RWORK (workspace) REAL array, dimension (N) */
/* RESID (output) REAL */
/* The maximum over the number of right hand sides of */
/* norm(B - A*X) / ( norm(A) * norm(X) * EPS ). */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Quick exit if N = 0 or NRHS = 0. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
x_dim1 = *ldx;
x_offset = 1 + x_dim1;
x -= x_offset;
b_dim1 = *ldb;
b_offset = 1 + b_dim1;
b -= b_offset;
--rwork;
/* Function Body */
if (*n <= 0 || *nrhs <= 0) {
*resid = 0.f;
return 0;
}
/* Exit with RESID = 1/EPS if ANORM = 0. */
eps = slamch_("Epsilon");
anorm = slansb_("1", uplo, n, kd, &a[a_offset], lda, &rwork[1]);
if (anorm <= 0.f) {
*resid = 1.f / eps;
return 0;
}
/* Compute B - A*X */
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
ssbmv_(uplo, n, kd, &c_b5, &a[a_offset], lda, &x[j * x_dim1 + 1], &
c__1, &c_b7, &b[j * b_dim1 + 1], &c__1);
/* L10: */
}
/* Compute the maximum over the number of right hand sides of */
/* norm( B - A*X ) / ( norm(A) * norm(X) * EPS ) */
*resid = 0.f;
i__1 = *nrhs;
for (j = 1; j <= i__1; ++j) {
bnorm = sasum_(n, &b[j * b_dim1 + 1], &c__1);
xnorm = sasum_(n, &x[j * x_dim1 + 1], &c__1);
if (xnorm <= 0.f) {
*resid = 1.f / eps;
} else {
/* Computing MAX */
r__1 = *resid, r__2 = bnorm / anorm / xnorm / eps;
*resid = dmax(r__1,r__2);
}
/* L20: */
}
return 0;
/* End of SPBT02 */
} /* spbt02_ */
