/* ./src_f77/zpptrs.f -- translated by f2c (version 20030320).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include <punc/vf2c.h>

/* Table of constant values */

static integer c__1 = 1;

/* Subroutine */ int zpptrs_(char *uplo, integer *n, integer *nrhs, 
	doublecomplex *ap, doublecomplex *b, integer *ldb, integer *info, 
	ftnlen uplo_len)
{
    /* System generated locals */
    integer b_dim1, b_offset, i__1;

    /* Local variables */
    static integer i__;
    extern logical lsame_(char *, char *, ftnlen, ftnlen);
    static logical upper;
    extern /* Subroutine */ int ztpsv_(char *, char *, char *, integer *, 
	    doublecomplex *, doublecomplex *, integer *, ftnlen, ftnlen, 
	    ftnlen), xerbla_(char *, integer *, ftnlen);


/*  -- LAPACK routine (version 3.0) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., */
/*     Courant Institute, Argonne National Lab, and Rice University */
/*     September 30, 1994 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZPPTRS 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 ZPPTRF. */

/*  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*16 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*16 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", (ftnlen)1, (ftnlen)1);
    if (! upper && ! lsame_(uplo, "L", (ftnlen)1, (ftnlen)1)) {
	*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_("ZPPTRS", &i__1, (ftnlen)6);
	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. */

	    ztpsv_("Upper", "Conjugate transpose", "Non-unit", n, &ap[1], &b[
		    i__ * b_dim1 + 1], &c__1, (ftnlen)5, (ftnlen)19, (ftnlen)
		    8);

/*           Solve U*X = B, overwriting B with X. */

	    ztpsv_("Upper", "No transpose", "Non-unit", n, &ap[1], &b[i__ * 
		    b_dim1 + 1], &c__1, (ftnlen)5, (ftnlen)12, (ftnlen)8);
/* 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. */

	    ztpsv_("Lower", "No transpose", "Non-unit", n, &ap[1], &b[i__ * 
		    b_dim1 + 1], &c__1, (ftnlen)5, (ftnlen)12, (ftnlen)8);

/*           Solve L'*X = Y, overwriting B with X. */

	    ztpsv_("Lower", "Conjugate transpose", "Non-unit", n, &ap[1], &b[
		    i__ * b_dim1 + 1], &c__1, (ftnlen)5, (ftnlen)19, (ftnlen)
		    8);
/* L20: */
	}
    }

    return 0;

/*     End of ZPPTRS */

} /* zpptrs_ */

