#include "blaswrap.h" #include "f2c.h" /* Subroutine */ int ctptrs_(char *uplo, char *trans, char *diag, integer *n, integer *nrhs, complex *ap, complex *b, integer *ldb, integer *info) { /* -- LAPACK routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 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. ===================================================================== Test the input parameters. Parameter adjustments */ /* Table of constant values */ static integer c__1 = 1; /* System generated locals */ integer b_dim1, b_offset, i__1, i__2; /* Local variables */ static integer j, jc; extern logical lsame_(char *, char *); static logical upper; extern /* Subroutine */ int ctpsv_(char *, char *, char *, integer *, complex *, complex *, integer *), xerbla_( char *, integer *); static logical nounit; --ap; b_dim1 = *ldb; b_offset = 1 + b_dim1; b -= b_offset; /* Function Body */ *info = 0; upper = lsame_(uplo, "U"); nounit = lsame_(diag, "N"); if (! upper && ! lsame_(uplo, "L")) { *info = -1; } else if (! lsame_(trans, "N") && ! lsame_(trans, "T") && ! lsame_(trans, "C")) { *info = -2; } else if (! nounit && ! lsame_(diag, "U")) { *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); 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); /* L30: */ } return 0; /* End of CTPTRS */ } /* ctptrs_ */