extern "C" magma_int_t
magma_dgeqp3( magma_int_t m, magma_int_t n,
double *A, magma_int_t lda,
magma_int_t *jpvt, double *tau,
double *work, magma_int_t lwork,
#if defined(PRECISION_z) || defined(PRECISION_c)
double *rwork,
#endif
magma_int_t *info )
{
/* -- MAGMA (version 1.4.0) --
Univ. of Tennessee, Knoxville
Univ. of California, Berkeley
Univ. of Colorado, Denver
August 2013
Purpose
=======
DGEQP3 computes a QR factorization with column pivoting of a
matrix A: A*P = Q*R using Level 3 BLAS.
Arguments
=========
M (input) INTEGER
The number of rows of the matrix A. M >= 0.
N (input) INTEGER
The number of columns of the matrix A. N >= 0.
A (input/output) DOUBLE_PRECISION array, dimension (LDA,N)
On entry, the M-by-N matrix A.
On exit, the upper triangle of the array contains the
min(M,N)-by-N upper trapezoidal matrix R; the elements below
the diagonal, together with the array TAU, represent the
unitary matrix Q as a product of min(M,N) elementary
reflectors.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,M).
JPVT (input/output) INTEGER array, dimension (N)
On entry, if JPVT(J).ne.0, the J-th column of A is permuted
to the front of A*P (a leading column); if JPVT(J)=0,
the J-th column of A is a free column.
On exit, if JPVT(J)=K, then the J-th column of A*P was the
the K-th column of A.
TAU (output) DOUBLE_PRECISION array, dimension (min(M,N))
The scalar factors of the elementary reflectors.
WORK (workspace/output) DOUBLE_PRECISION array, dimension (MAX(1,LWORK))
On exit, if INFO=0, WORK(1) returns the optimal LWORK.
LWORK (input) INTEGER
The dimension of the array WORK.
For [sd]geqp3, LWORK >= (N+1)*NB + 2*N;
for [cz]geqp3, LWORK >= (N+1)*NB,
where NB is the optimal blocksize.
If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
For [cz]geqp3 only:
RWORK (workspace) DOUBLE PRECISION array, dimension (2*N)
INFO (output) INTEGER
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
Further Details
===============
The matrix Q is represented as a product of elementary reflectors
Q = H(1) H(2) . . . H(k), where k = min(m,n).
Each H(i) has the form
H(i) = I - tau * v * v'
where tau is a real scalar, and v is a real vector
with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in
A(i+1:m,i), and tau in TAU(i).
===================================================================== */
#define A(i, j) (A + (i) + (j)*(lda ))
#define dA(i, j) (dwork + (i) + (j)*(ldda))
double *dwork, *df;
magma_int_t ione = 1;
magma_int_t n_j, ldda, ldwork;
magma_int_t j, jb, na, nb, sm, sn, fjb, nfxd, minmn;
magma_int_t topbmn, sminmn, lwkopt, lquery;
*info = 0;
lquery = (lwork == -1);
if (m < 0) {
*info = -1;
} else if (n < 0) {
*info = -2;
} else if (lda < max(1,m)) {
*info = -4;
}
nb = magma_get_dgeqp3_nb(min(m, n));
if (*info == 0) {
minmn = min(m,n);
if (minmn == 0) {
lwkopt = 1;
} else {
lwkopt = (n + 1)*nb;
#if defined(PRECISION_d) || defined(PRECISION_s)
lwkopt += 2*n;
#endif
}
work[0] = MAGMA_D_MAKE( lwkopt, 0. );
if (lwork < lwkopt && ! lquery) {
*info = -8;
}
}
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
} else if (lquery) {
return *info;
}
if (minmn == 0)
return *info;
#if defined(PRECISION_d) || defined(PRECISION_s)
double *rwork = work + (n + 1)*nb;
#endif
ldda = ((m+31)/32)*32;
ldwork = n*ldda + (n+1)*nb;
if (MAGMA_SUCCESS != magma_dmalloc( &dwork, ldwork )) {
*info = MAGMA_ERR_DEVICE_ALLOC;
return *info;
}
df = dwork + n*ldda;
// dwork used for dA
magma_queue_t stream;
magma_queue_create( &stream );
/* Move initial columns up front.
* Note jpvt uses 1-based indices for historical compatibility. */
nfxd = 0;
for (j = 0; j < n; ++j) {
if (jpvt[j] != 0) {
if (j != nfxd) {
blasf77_dswap(&m, A(0, j), &ione, A(0, nfxd), &ione);
jpvt[j] = jpvt[nfxd];
jpvt[nfxd] = j + 1;
}
else {
jpvt[j] = j + 1;
}
++nfxd;
}
else {
jpvt[j] = j + 1;
}
}
/* Factorize fixed columns
=======================
Compute the QR factorization of fixed columns and update
remaining columns. */
if (nfxd > 0) {
na = min(m,nfxd);
lapackf77_dgeqrf(&m, &na, A, &lda, tau, work, &lwork, info);
if (na < n) {
n_j = n - na;
lapackf77_dormqr( MagmaLeftStr, MagmaTransStr, &m, &n_j, &na,
A, &lda, tau, A(0, na), &lda,
work, &lwork, info );
}
}
/* Factorize free columns */
if (nfxd < minmn) {
sm = m - nfxd;
sn = n - nfxd;
sminmn = minmn - nfxd;
if (nb < sminmn) {
j = nfxd;
// Set the original matrix to the GPU
magma_dsetmatrix_async( m, sn,
A (0,j), lda,
dA(0,j), ldda, stream );
}
/* Initialize partial column norms. */
for (j = nfxd; j < n; ++j) {
rwork[j] = cblas_dnrm2(sm, A(nfxd, j), ione);
rwork[n + j] = rwork[j];
}
j = nfxd;
if (nb < sminmn) {
/* Use blocked code initially. */
magma_queue_sync( stream );
/* Compute factorization: while loop. */
topbmn = minmn - nb;
while(j < topbmn) {
jb = min(nb, topbmn - j);
/* Factorize JB columns among columns J:N. */
n_j = n - j;
if (j>nfxd) {
// Get panel to the CPU
magma_dgetmatrix( m-j, jb,
dA(j,j), ldda,
A (j,j), lda );
// Get the rows
magma_dgetmatrix( jb, n_j - jb,
dA(j,j + jb), ldda,
A (j,j + jb), lda );
}
magma_dlaqps( m, n_j, j, jb, &fjb,
A (0, j), lda,
dA(0, j), ldda,
&jpvt[j], &tau[j], &rwork[j], &rwork[n + j],
work,
&work[jb], n_j,
&df[jb], n_j );
j += fjb; /* fjb is actual number of columns factored */
}
}
/* Use unblocked code to factor the last or only block. */
if (j < minmn) {
n_j = n - j;
if (j > nfxd) {
magma_dgetmatrix( m-j, n_j,
dA(j,j), ldda,
A (j,j), lda );
}
lapackf77_dlaqp2(&m, &n_j, &j, A(0, j), &lda, &jpvt[j],
&tau[j], &rwork[j], &rwork[n+j], work );
}
}
work[0] = MAGMA_D_MAKE( lwkopt, 0. );
magma_free( dwork );
magma_queue_destroy( stream );
return *info;
} /* dgeqp3 */
/**
Purpose
-------
DGEQP3 computes a QR factorization with column pivoting of a
matrix A: A*P = Q*R using Level 3 BLAS.
Arguments
---------
@param[in]
m INTEGER
The number of rows of the matrix A. M >= 0.
@param[in]
n INTEGER
The number of columns of the matrix A. N >= 0.
@param[in,out]
A DOUBLE_PRECISION array, dimension (LDA,N)
On entry, the M-by-N matrix A.
On exit, the upper triangle of the array contains the
min(M,N)-by-N upper trapezoidal matrix R; the elements below
the diagonal, together with the array TAU, represent the
unitary matrix Q as a product of min(M,N) elementary
reflectors.
@param[in]
lda INTEGER
The leading dimension of the array A. LDA >= max(1,M).
@param[in,out]
jpvt INTEGER array, dimension (N)
On entry, if JPVT(J).ne.0, the J-th column of A is permuted
to the front of A*P (a leading column); if JPVT(J)=0,
the J-th column of A is a free column.
On exit, if JPVT(J)=K, then the J-th column of A*P was the
the K-th column of A.
@param[out]
tau DOUBLE_PRECISION array, dimension (min(M,N))
The scalar factors of the elementary reflectors.
@param[out]
work (workspace) DOUBLE_PRECISION array, dimension (MAX(1,LWORK))
On exit, if INFO=0, WORK[0] returns the optimal LWORK.
@param[in]
lwork INTEGER
The dimension of the array WORK.
For [sd]geqp3, LWORK >= (N+1)*NB + 2*N;
for [cz]geqp3, LWORK >= (N+1)*NB,
where NB is the optimal blocksize.
\n
If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
@param
rwork (workspace, for [cz]geqp3 only) DOUBLE PRECISION array, dimension (2*N)
@param[out]
info INTEGER
- = 0: successful exit.
- < 0: if INFO = -i, the i-th argument had an illegal value.
Further Details
---------------
The matrix Q is represented as a product of elementary reflectors
Q = H(1) H(2) . . . H(k), where k = min(m,n).
Each H(i) has the form
H(i) = I - tau * v * v'
where tau is a real scalar, and v is a real vector
with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in
A(i+1:m,i), and tau in TAU(i).
@ingroup magma_dgeqp3_comp
********************************************************************/
extern "C" magma_int_t
magma_dgeqp3(
magma_int_t m, magma_int_t n,
double *A, magma_int_t lda,
magma_int_t *jpvt, double *tau,
double *work, magma_int_t lwork,
#ifdef COMPLEX
double *rwork,
#endif
magma_int_t *info )
{
#define A(i, j) (A + (i) + (j)*(lda ))
#define dA(i, j) (dwork + (i) + (j)*(ldda))
double *dwork, *df;
magma_int_t ione = 1;
magma_int_t n_j, ldda, ldwork;
magma_int_t j, jb, na, nb, sm, sn, fjb, nfxd, minmn;
magma_int_t topbmn, sminmn, lwkopt=0, lquery;
*info = 0;
lquery = (lwork == -1);
if (m < 0) {
*info = -1;
} else if (n < 0) {
*info = -2;
} else if (lda < max(1,m)) {
*info = -4;
}
nb = magma_get_dgeqp3_nb(min(m, n));
minmn = min(m,n);
if (*info == 0) {
if (minmn == 0) {
lwkopt = 1;
} else {
lwkopt = (n + 1)*nb;
#ifdef REAL
lwkopt += 2*n;
#endif
}
work[0] = MAGMA_D_MAKE( lwkopt, 0. );
if (lwork < lwkopt && ! lquery) {
*info = -8;
}
}
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
} else if (lquery) {
return *info;
}
if (minmn == 0)
return *info;
#ifdef REAL
double *rwork = work + (n + 1)*nb;
#endif
ldda = ((m+31)/32)*32;
ldwork = n*ldda + (n+1)*nb;
if (MAGMA_SUCCESS != magma_dmalloc( &dwork, ldwork )) {
*info = MAGMA_ERR_DEVICE_ALLOC;
return *info;
}
df = dwork + n*ldda;
// dwork used for dA
magma_queue_t stream;
magma_queue_create( &stream );
/* Move initial columns up front.
* Note jpvt uses 1-based indices for historical compatibility. */
nfxd = 0;
for (j = 0; j < n; ++j) {
if (jpvt[j] != 0) {
if (j != nfxd) {
blasf77_dswap(&m, A(0, j), &ione, A(0, nfxd), &ione);
jpvt[j] = jpvt[nfxd];
jpvt[nfxd] = j + 1;
}
else {
jpvt[j] = j + 1;
}
++nfxd;
}
else {
jpvt[j] = j + 1;
}
}
/* Factorize fixed columns
=======================
Compute the QR factorization of fixed columns and update
remaining columns. */
if (nfxd > 0) {
na = min(m,nfxd);
lapackf77_dgeqrf(&m, &na, A, &lda, tau, work, &lwork, info);
if (na < n) {
n_j = n - na;
lapackf77_dormqr( MagmaLeftStr, MagmaConjTransStr, &m, &n_j, &na,
A, &lda, tau, A(0, na), &lda,
work, &lwork, info );
}
}
/* Factorize free columns */
if (nfxd < minmn) {
sm = m - nfxd;
sn = n - nfxd;
sminmn = minmn - nfxd;
if (nb < sminmn) {
j = nfxd;
// Set the original matrix to the GPU
magma_dsetmatrix_async( m, sn,
A (0,j), lda,
dA(0,j), ldda, stream );
}
/* Initialize partial column norms. */
for (j = nfxd; j < n; ++j) {
rwork[j] = magma_cblas_dnrm2( sm, A(nfxd,j), ione );
rwork[n + j] = rwork[j];
}
j = nfxd;
if (nb < sminmn) {
/* Use blocked code initially. */
magma_queue_sync( stream );
/* Compute factorization: while loop. */
topbmn = minmn - nb;
while(j < topbmn) {
jb = min(nb, topbmn - j);
/* Factorize JB columns among columns J:N. */
n_j = n - j;
if (j > nfxd) {
// Get panel to the CPU
magma_dgetmatrix( m-j, jb,
dA(j,j), ldda,
A (j,j), lda );
// Get the rows
magma_dgetmatrix( jb, n_j - jb,
dA(j,j + jb), ldda,
A (j,j + jb), lda );
}
magma_dlaqps( m, n_j, j, jb, &fjb,
A (0, j), lda,
dA(0, j), ldda,
&jpvt[j], &tau[j], &rwork[j], &rwork[n + j],
work,
&work[jb], n_j,
&df[jb], n_j );
j += fjb; /* fjb is actual number of columns factored */
}
}
/* Use unblocked code to factor the last or only block. */
if (j < minmn) {
n_j = n - j;
if (j > nfxd) {
magma_dgetmatrix( m-j, n_j,
dA(j,j), ldda,
A (j,j), lda );
}
lapackf77_dlaqp2(&m, &n_j, &j, A(0, j), &lda, &jpvt[j],
&tau[j], &rwork[j], &rwork[n+j], work );
}
}
work[0] = MAGMA_D_MAKE( lwkopt, 0. );
magma_free( dwork );
magma_queue_destroy( stream );
return *info;
} /* magma_dgeqp3 */