void LDLSolve(scs_float *x, scs_float b[], cs * L, scs_float D[], scs_int P[], scs_float * bp) {
/* solves PLDL'P' x = b for x */
scs_int n = L->n;
if (P == NULL) {
if (x != b) /* if they're different addresses */
memcpy(x, b, n * sizeof(scs_float));
LDL_lsolve(n, x, L->p, L->i, L->x);
LDL_dsolve(n, x, D);
LDL_ltsolve(n, x, L->p, L->i, L->x);
} else {
LDL_perm(n, bp, b, P);
LDL_lsolve(n, bp, L->p, L->i, L->x);
LDL_dsolve(n, bp, D);
LDL_ltsolve(n, bp, L->p, L->i, L->x);
LDL_permt(n, x, bp, P);
}
}
int main (void)
#endif
{
/* ---------------------------------------------------------------------- */
/* local variables */
/* ---------------------------------------------------------------------- */
#ifdef USE_AMD
double Info [AMD_INFO] ;
#endif
double r, rnorm, flops, maxrnorm = 0. ;
double *Ax, *Lx, *B, *D, *X, *Y ;
LDL_int matrix, *Ai, *Ap, *Li, *Lp, *P, *Pinv, *Perm, *PermInv, n, i, j, p,
nz, *Flag, *Pattern, *Lnz, *Parent, trial, lnz, d, jumbled ;
FILE *f ;
char s [LEN] ;
/* ---------------------------------------------------------------------- */
/* check the error-checking routines with null matrices */
/* ---------------------------------------------------------------------- */
i = 1 ;
n = -1 ;
if (LDL_valid_perm (n, (LDL_int *) NULL, &i)
|| !LDL_valid_perm (0, (LDL_int *) NULL, &i)
|| LDL_valid_matrix (n, (LDL_int *) NULL, (LDL_int *) NULL)
|| LDL_valid_matrix (0, &i, &i))
{
printf (PROGRAM ": ldl error-checking routine failed\n") ;
EXIT_ERROR ;
}
/* ---------------------------------------------------------------------- */
/* read in a factorize a set of matrices */
/* ---------------------------------------------------------------------- */
for (matrix = 1 ; matrix <= NMATRICES ; matrix++)
{
/* ------------------------------------------------------------------ */
/* read in the matrix and the permutation */
/* ------------------------------------------------------------------ */
sprintf (s, "../Matrix/A%02d", (int) matrix) ;
if ((f = fopen (s, "r")) == (FILE *) NULL)
{
printf (PROGRAM ": could not open file: %s\n", s) ;
EXIT_ERROR ;
}
fgets (s, LEN, f) ;
printf ("\n\n--------------------------------------------------------");
printf ("\nInput matrix: %s", s) ;
printf ("--------------------------------------------------------\n\n");
fscanf (f, LDL_ID " " LDL_ID, &n, &jumbled) ;
n = (n < 0) ? (0) : (n) ;
ALLOC_MEMORY (P, LDL_int, n) ;
ALLOC_MEMORY (Ap, LDL_int, n+1) ;
for (j = 0 ; j <= n ; j++)
{
fscanf (f, LDL_ID, &Ap [j]) ;
}
nz = Ap [n] ;
ALLOC_MEMORY (Ai, LDL_int, nz) ;
ALLOC_MEMORY (Ax, double, nz) ;
for (p = 0 ; p < nz ; p++)
{
fscanf (f, LDL_ID , &Ai [p]) ;
}
for (p = 0 ; p < nz ; p++)
{
fscanf (f, "%lg", &Ax [p]) ;
}
for (j = 0 ; j < n ; j++)
{
fscanf (f, LDL_ID , &P [j]) ;
}
fclose (f) ;
/* ------------------------------------------------------------------ */
/* check the matrix A and the permutation P */
/* ------------------------------------------------------------------ */
ALLOC_MEMORY (Flag, LDL_int, n) ;
/* To test the error-checking routines, some of the input matrices
* are not valid. So this error is expected to occur. */
if (!LDL_valid_matrix (n, Ap, Ai) || !LDL_valid_perm (n, P, Flag))
{
printf (PROGRAM ": invalid matrix and/or permutation\n") ;
FREE_MEMORY (P, LDL_int) ;
FREE_MEMORY (Ap, LDL_int) ;
FREE_MEMORY (Ai, LDL_int) ;
FREE_MEMORY (Ax, double) ;
FREE_MEMORY (Flag, LDL_int) ;
continue ;
}
/* ------------------------------------------------------------------ */
/* get the AMD permutation, if available */
/* ------------------------------------------------------------------ */
#ifdef USE_AMD
/* recompute the permutation with AMD */
/* Assume that AMD produces a valid permutation P. */
#ifdef LDL_LONG
if (amd_l_order (n, Ap, Ai, P, (double *) NULL, Info) < AMD_OK)
{
printf (PROGRAM ": call to AMD failed\n") ;
EXIT_ERROR ;
}
amd_l_control ((double *) NULL) ;
amd_l_info (Info) ;
#else
if (amd_order (n, Ap, Ai, P, (double *) NULL, Info) < AMD_OK)
{
printf (PROGRAM ": call to AMD failed\n") ;
EXIT_ERROR ;
}
amd_control ((double *) NULL) ;
amd_info (Info) ;
#endif
#endif
/* ------------------------------------------------------------------ */
/* allocate workspace and the first part of LDL factorization */
/* ------------------------------------------------------------------ */
ALLOC_MEMORY (Pinv, LDL_int, n) ;
ALLOC_MEMORY (Y, double, n) ;
ALLOC_MEMORY (Pattern, LDL_int, n) ;
ALLOC_MEMORY (Lnz, LDL_int, n) ;
ALLOC_MEMORY (Lp, LDL_int, n+1) ;
ALLOC_MEMORY (Parent, LDL_int, n) ;
ALLOC_MEMORY (D, double, n) ;
ALLOC_MEMORY (B, double, n) ;
ALLOC_MEMORY (X, double, n) ;
/* ------------------------------------------------------------------ */
/* factorize twice, with and without permutation */
/* ------------------------------------------------------------------ */
for (trial = 1 ; trial <= 2 ; trial++)
{
if (trial == 1)
{
printf ("Factorize PAP'=LDL' and solve Ax=b\n") ;
Perm = P ;
PermInv = Pinv ;
}
else
{
printf ("Factorize A=LDL' and solve Ax=b\n") ;
Perm = (LDL_int *) NULL ;
PermInv = (LDL_int *) NULL ;
}
/* -------------------------------------------------------------- */
/* symbolic factorization to get Lp, Parent, Lnz, and Pinv */
/* -------------------------------------------------------------- */
LDL_symbolic (n, Ap, Ai, Lp, Parent, Lnz, Flag, Perm, PermInv) ;
lnz = Lp [n] ;
/* find # of nonzeros in L, and flop count for LDL_numeric */
flops = 0 ;
for (j = 0 ; j < n ; j++)
{
flops += ((double) Lnz [j]) * (Lnz [j] + 2) ;
}
printf ("Nz in L: "LDL_ID" Flop count: %g\n", lnz, flops) ;
/* -------------------------------------------------------------- */
/* allocate remainder of L, of size lnz */
/* -------------------------------------------------------------- */
ALLOC_MEMORY (Li, LDL_int, lnz) ;
ALLOC_MEMORY (Lx, double, lnz) ;
/* -------------------------------------------------------------- */
/* numeric factorization to get Li, Lx, and D */
/* -------------------------------------------------------------- */
d = LDL_numeric (n, Ap, Ai, Ax, Lp, Parent, Lnz, Li, Lx, D,
Y, Flag, Pattern, Perm, PermInv) ;
/* -------------------------------------------------------------- */
/* solve, or report singular case */
/* -------------------------------------------------------------- */
if (d != n)
{
printf ("Ax=b not solved since D("LDL_ID","LDL_ID") is zero.\n", d, d) ;
}
else
{
/* construct the right-hand-side, B */
for (i = 0 ; i < n ; i++)
{
B [i] = 1 + ((double) i) / 100 ;
}
/* solve Ax=b */
if (trial == 1)
{
/* the factorization is LDL' = PAP' */
LDL_perm (n, Y, B, P) ; /* y = Pb */
LDL_lsolve (n, Y, Lp, Li, Lx) ; /* y = L\y */
LDL_dsolve (n, Y, D) ; /* y = D\y */
LDL_ltsolve (n, Y, Lp, Li, Lx) ; /* y = L'\y */
LDL_permt (n, X, Y, P) ; /* x = P'y */
}
else
{
/* the factorization is LDL' = A */
for (i = 0 ; i < n ; i++) /* x = b */
{
X [i] = B [i] ;
}
LDL_lsolve (n, X, Lp, Li, Lx) ; /* x = L\x */
LDL_dsolve (n, X, D) ; /* x = D\x */
LDL_ltsolve (n, X, Lp, Li, Lx) ; /* x = L'\x */
}
/* compute the residual y = Ax-b */
/* note that this code can tolerate a jumbled matrix */
for (i = 0 ; i < n ; i++)
{
Y [i] = -B [i] ;
}
for (j = 0 ; j < n ; j++)
{
for (p = Ap [j] ; p < Ap [j+1] ; p++)
{
Y [Ai [p]] += Ax [p] * X [j] ;
}
}
/* rnorm = norm (y, inf) */
rnorm = 0 ;
for (i = 0 ; i < n ; i++)
{
r = (Y [i] > 0) ? (Y [i]) : (-Y [i]) ;
rnorm = (r > rnorm) ? (r) : (rnorm) ;
}
maxrnorm = (rnorm > maxrnorm) ? (rnorm) : (maxrnorm) ;
printf ("relative maxnorm of residual: %g\n", rnorm) ;
}
/* -------------------------------------------------------------- */
/* free the size-lnz part of L */
/* -------------------------------------------------------------- */
FREE_MEMORY (Li, LDL_int) ;
FREE_MEMORY (Lx, double) ;
}
/* free everything */
FREE_MEMORY (P, LDL_int) ;
FREE_MEMORY (Ap, LDL_int) ;
FREE_MEMORY (Ai, LDL_int) ;
FREE_MEMORY (Ax, double) ;
FREE_MEMORY (Pinv, LDL_int) ;
FREE_MEMORY (Y, double) ;
FREE_MEMORY (Flag, LDL_int) ;
FREE_MEMORY (Pattern, LDL_int) ;
FREE_MEMORY (Lnz, LDL_int) ;
FREE_MEMORY (Lp, LDL_int) ;
FREE_MEMORY (Parent, LDL_int) ;
FREE_MEMORY (D, double) ;
FREE_MEMORY (B, double) ;
FREE_MEMORY (X, double) ;
}
printf ("\nLargest residual during all tests: %g\n", maxrnorm) ;
if (maxrnorm < 1e-8)
{
printf ("\n" PROGRAM ": all tests passed\n") ;
EXIT_OK ;
}
else
{
printf ("\n" PROGRAM ": one more tests failed (residual too high)\n") ;
EXIT_ERROR ;
}
}
