798c448b0c
1. Replaced all instances of "int" with "blasint" 2. Added string length as "hidden" third parameter in calls to fortran XERBLA
108 lines
2.9 KiB
C
108 lines
2.9 KiB
C
#include "relapack.h"
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static void RELAPACK_strtri_rec(const char *, const char *, const blasint *,
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float *, const blasint *, blasint *);
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/** CTRTRI computes the inverse of a real upper or lower triangular matrix A.
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*
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* This routine is functionally equivalent to LAPACK's strtri.
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* For details on its interface, see
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* http://www.netlib.org/lapack/explore-html/de/d76/strtri_8f.html
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* */
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void RELAPACK_strtri(
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const char *uplo, const char *diag, const blasint *n,
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float *A, const blasint *ldA,
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blasint *info
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) {
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// Check arguments
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const blasint lower = LAPACK(lsame)(uplo, "L");
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const blasint upper = LAPACK(lsame)(uplo, "U");
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const blasint nounit = LAPACK(lsame)(diag, "N");
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const blasint unit = LAPACK(lsame)(diag, "U");
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*info = 0;
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if (!lower && !upper)
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*info = -1;
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else if (!nounit && !unit)
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*info = -2;
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else if (*n < 0)
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*info = -3;
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else if (*ldA < MAX(1, *n))
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*info = -5;
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if (*info) {
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const blasint minfo = -*info;
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LAPACK(xerbla)("STRTRI", &minfo, strlen("STRTRI"));
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return;
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}
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// Clean char * arguments
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const char cleanuplo = lower ? 'L' : 'U';
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const char cleandiag = nounit ? 'N' : 'U';
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// check for singularity
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if (nounit) {
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blasint i;
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for (i = 0; i < *n; i++)
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if (A[i + *ldA * i] == 0) {
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*info = i;
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return;
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}
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}
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// Recursive kernel
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RELAPACK_strtri_rec(&cleanuplo, &cleandiag, n, A, ldA, info);
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}
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/** strtri's recursive compute kernel */
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static void RELAPACK_strtri_rec(
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const char *uplo, const char *diag, const blasint *n,
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float *A, const blasint *ldA,
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blasint *info
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){
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if (*n <= MAX(CROSSOVER_STRTRI, 1)) {
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// Unblocked
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LAPACK(strti2)(uplo, diag, n, A, ldA, info);
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return;
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}
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// Constants
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const float ONE[] = { 1. };
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const float MONE[] = { -1. };
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// Splitting
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const blasint n1 = SREC_SPLIT(*n);
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const blasint n2 = *n - n1;
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// A_TL A_TR
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// A_BL A_BR
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float *const A_TL = A;
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float *const A_TR = A + *ldA * n1;
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float *const A_BL = A + n1;
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float *const A_BR = A + *ldA * n1 + n1;
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// recursion(A_TL)
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RELAPACK_strtri_rec(uplo, diag, &n1, A_TL, ldA, info);
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if (*info)
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return;
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if (*uplo == 'L') {
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// A_BL = - A_BL * A_TL
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BLAS(strmm)("R", "L", "N", diag, &n2, &n1, MONE, A_TL, ldA, A_BL, ldA);
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// A_BL = A_BR \ A_BL
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BLAS(strsm)("L", "L", "N", diag, &n2, &n1, ONE, A_BR, ldA, A_BL, ldA);
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} else {
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// A_TR = - A_TL * A_TR
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BLAS(strmm)("L", "U", "N", diag, &n1, &n2, MONE, A_TL, ldA, A_TR, ldA);
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// A_TR = A_TR / A_BR
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BLAS(strsm)("R", "U", "N", diag, &n1, &n2, ONE, A_BR, ldA, A_TR, ldA);
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}
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// recursion(A_BR)
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RELAPACK_strtri_rec(uplo, diag, &n2, A_BR, ldA, info);
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if (*info)
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*info += n1;
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}
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