/* ./src_f77/ctptrs.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 ctptrs_(char *uplo, char *trans, char *diag, integer *n, 
	integer *nrhs, complex *ap, complex *b, integer *ldb, integer *info, 
	ftnlen uplo_len, ftnlen trans_len, ftnlen diag_len)
{
    /* System generated locals */
    integer b_dim1, b_offset, i__1, i__2;

    /* Local variables */
    static integer j, jc;
    extern logical lsame_(char *, char *, ftnlen, ftnlen);
    static logical upper;
    extern /* Subroutine */ int ctpsv_(char *, char *, char *, integer *, 
	    complex *, complex *, integer *, ftnlen, ftnlen, ftnlen), xerbla_(
	    char *, integer *, ftnlen);
    static logical nounit;


/*  -- 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 */
/*  ======= */

/*  CTPTRS solves a triangular system of the form */

/*     A * X = B,  A**T * X = B,  or  A**H * X = B, */

/*  where A is a triangular matrix of order N stored in packed format, */
/*  and B is an N-by-NRHS matrix.  A check is made to verify that A is */
/*  nonsingular. */

/*  Arguments */
/*  ========= */

/*  UPLO    (input) CHARACTER*1 */
/*          = 'U':  A is upper triangular; */
/*          = 'L':  A is lower triangular. */

/*  TRANS   (input) CHARACTER*1 */
/*          Specifies the form of the system of equations: */
/*          = 'N':  A * X = B     (No transpose) */
/*          = 'T':  A**T * X = B  (Transpose) */
/*          = 'C':  A**H * X = B  (Conjugate transpose) */

/*  DIAG    (input) CHARACTER*1 */
/*          = 'N':  A is non-unit triangular; */
/*          = 'U':  A is unit triangular. */

/*  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 upper or lower triangular matrix A, packed columnwise in */
/*          a linear array.  The j-th column of A is stored in the array */
/*          AP as follows: */
/*          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; */
/*          if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n. */

/*  B       (input/output) COMPLEX array, dimension (LDB,NRHS) */
/*          On entry, the right hand side matrix B. */
/*          On exit, if INFO = 0, 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 */
/*          > 0:  if INFO = i, the i-th diagonal element of A is zero, */
/*                indicating that the matrix is singular and the */
/*                solutions X have not been computed. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. 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);
    nounit = lsame_(diag, "N", (ftnlen)1, (ftnlen)1);
    if (! upper && ! lsame_(uplo, "L", (ftnlen)1, (ftnlen)1)) {
	*info = -1;
    } else if (! lsame_(trans, "N", (ftnlen)1, (ftnlen)1) && ! lsame_(trans, 
	    "T", (ftnlen)1, (ftnlen)1) && ! lsame_(trans, "C", (ftnlen)1, (
	    ftnlen)1)) {
	*info = -2;
    } else if (! nounit && ! lsame_(diag, "U", (ftnlen)1, (ftnlen)1)) {
	*info = -3;
    } else if (*n < 0) {
	*info = -4;
    } else if (*nrhs < 0) {
	*info = -5;
    } else if (*ldb < max(1,*n)) {
	*info = -8;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("CTPTRS", &i__1, (ftnlen)6);
	return 0;
    }

/*     Quick return if possible */

    if (*n == 0) {
	return 0;
    }

/*     Check for singularity. */

    if (nounit) {
	if (upper) {
	    jc = 1;
	    i__1 = *n;
	    for (*info = 1; *info <= i__1; ++(*info)) {
		i__2 = jc + *info - 1;
		if (ap[i__2].r == 0.f && ap[i__2].i == 0.f) {
		    return 0;
		}
		jc += *info;
/* L10: */
	    }
	} else {
	    jc = 1;
	    i__1 = *n;
	    for (*info = 1; *info <= i__1; ++(*info)) {
		i__2 = jc;
		if (ap[i__2].r == 0.f && ap[i__2].i == 0.f) {
		    return 0;
		}
		jc = jc + *n - *info + 1;
/* L20: */
	    }
	}
    }
    *info = 0;

/*     Solve  A * x = b,  A**T * x = b,  or  A**H * x = b. */

    i__1 = *nrhs;
    for (j = 1; j <= i__1; ++j) {
	ctpsv_(uplo, trans, diag, n, &ap[1], &b[j * b_dim1 + 1], &c__1, (
		ftnlen)1, (ftnlen)1, (ftnlen)1);
/* L30: */
    }

    return 0;

/*     End of CTPTRS */

} /* ctptrs_ */

