/* cpptrs.f -- translated by f2c (version 20061008).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
#include "blaswrap.h"
/* Table of constant values */
static integer c__1 = 1;
/* Subroutine */ int cpptrs_(char *uplo, integer *n, integer *nrhs, complex *
ap, complex *b, integer *ldb, integer *info)
{
/* System generated locals */
integer b_dim1, b_offset, i__1;
/* Local variables */
integer i__;
extern logical lsame_(char *, char *);
logical upper;
extern /* Subroutine */ int ctpsv_(char *, char *, char *, integer *,
complex *, complex *, integer *), xerbla_(
char *, integer *);
/* -- LAPACK routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CPPTRS solves a system of linear equations A*X = B with a Hermitian */
/* positive definite matrix A in packed storage using the Cholesky */
/* factorization A = U**H*U or A = L*L**H computed by CPPTRF. */
/* Arguments */
/* ========= */
/* 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. */
/* NRHS (input) INTEGER */
/* The number of right hand sides, i.e., the number of columns */
/* of the matrix B. NRHS >= 0. */
/* AP (input) COMPLEX array, dimension (N*(N+1)/2) */
/* The triangular factor U or L from the Cholesky factorization */
/* A = U**H*U or A = L*L**H, packed columnwise in a linear */
/* array. The j-th column of U or L is stored in the array AP */
/* as follows: */
/* if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; */
/* if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n. */
/* B (input/output) COMPLEX array, dimension (LDB,NRHS) */
/* On entry, the right hand side matrix B. */
/* On exit, the solution matrix X. */
/* LDB (input) INTEGER */
/* The leading dimension of the array B. LDB >= max(1,N). */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* ===================================================================== */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
--ap;
b_dim1 = *ldb;
b_offset = 1 + b_dim1;
b -= b_offset;
/* Function Body */
*info = 0;
upper = lsame_(uplo, "U");
if (! upper && ! lsame_(uplo, "L")) {
*info = -1;
} else if (*n < 0) {
*info = -2;
} else if (*nrhs < 0) {
*info = -3;
} else if (*ldb < max(1,*n)) {
*info = -6;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CPPTRS", &i__1);
return 0;
}
/* Quick return if possible */
if (*n == 0 || *nrhs == 0) {
return 0;
}
if (upper) {
/* Solve A*X = B where A = U'*U. */
i__1 = *nrhs;
for (i__ = 1; i__ <= i__1; ++i__) {
/* Solve U'*X = B, overwriting B with X. */
ctpsv_("Upper", "Conjugate transpose", "Non-unit", n, &ap[1], &b[
i__ * b_dim1 + 1], &c__1);
/* Solve U*X = B, overwriting B with X. */
ctpsv_("Upper", "No transpose", "Non-unit", n, &ap[1], &b[i__ *
b_dim1 + 1], &c__1);
/* L10: */
}
} else {
/* Solve A*X = B where A = L*L'. */
i__1 = *nrhs;
for (i__ = 1; i__ <= i__1; ++i__) {
/* Solve L*Y = B, overwriting B with X. */
ctpsv_("Lower", "No transpose", "Non-unit", n, &ap[1], &b[i__ *
b_dim1 + 1], &c__1);
/* Solve L'*X = Y, overwriting B with X. */
ctpsv_("Lower", "Conjugate transpose", "Non-unit", n, &ap[1], &b[
i__ * b_dim1 + 1], &c__1);
/* L20: */
}
}
return 0;
/* End of CPPTRS */
} /* cpptrs_ */