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/* blas/source_trsv_r.h
*
* Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
{
const int nonunit = (Diag == CblasNonUnit);
INDEX ix, jx;
INDEX i, j;
const int Trans = (TransA != CblasConjTrans) ? TransA : CblasTrans;
if (N == 0)
return;
/* form x := inv( A )*x */
if ((order == CblasRowMajor && Trans == CblasNoTrans && Uplo == CblasUpper)
|| (order == CblasColMajor && Trans == CblasTrans && Uplo == CblasLower)) {
/* backsubstitution */
ix = OFFSET(N, incX) + incX * (N - 1);
if (nonunit) {
X[ix] = X[ix] / A[lda * (N - 1) + (N - 1)];
}
ix -= incX;
for (i = N - 1; i > 0 && i--;) {
BASE tmp = X[ix];
jx = ix + incX;
for (j = i + 1; j < N; j++) {
const BASE Aij = A[lda * i + j];
tmp -= Aij * X[jx];
jx += incX;
}
if (nonunit) {
X[ix] = tmp / A[lda * i + i];
} else {
X[ix] = tmp;
}
ix -= incX;
}
} else if ((order == CblasRowMajor && Trans == CblasNoTrans && Uplo == CblasLower)
|| (order == CblasColMajor && Trans == CblasTrans && Uplo == CblasUpper)) {
/* forward substitution */
ix = OFFSET(N, incX);
if (nonunit) {
X[ix] = X[ix] / A[lda * 0 + 0];
}
ix += incX;
for (i = 1; i < N; i++) {
BASE tmp = X[ix];
jx = OFFSET(N, incX);
for (j = 0; j < i; j++) {
const BASE Aij = A[lda * i + j];
tmp -= Aij * X[jx];
jx += incX;
}
if (nonunit) {
X[ix] = tmp / A[lda * i + i];
} else {
X[ix] = tmp;
}
ix += incX;
}
} else if ((order == CblasRowMajor && Trans == CblasTrans && Uplo == CblasUpper)
|| (order == CblasColMajor && Trans == CblasNoTrans && Uplo == CblasLower)) {
/* form x := inv( A' )*x */
/* forward substitution */
ix = OFFSET(N, incX);
if (nonunit) {
X[ix] = X[ix] / A[lda * 0 + 0];
}
ix += incX;
for (i = 1; i < N; i++) {
BASE tmp = X[ix];
jx = OFFSET(N, incX);
for (j = 0; j < i; j++) {
const BASE Aji = A[lda * j + i];
tmp -= Aji * X[jx];
jx += incX;
}
if (nonunit) {
X[ix] = tmp / A[lda * i + i];
} else {
X[ix] = tmp;
}
ix += incX;
}
} else if ((order == CblasRowMajor && Trans == CblasTrans && Uplo == CblasLower)
|| (order == CblasColMajor && Trans == CblasNoTrans && Uplo == CblasUpper)) {
/* backsubstitution */
ix = OFFSET(N, incX) + (N - 1) * incX;
if (nonunit) {
X[ix] = X[ix] / A[lda * (N - 1) + (N - 1)];
}
ix -= incX;
for (i = N - 1; i > 0 && i--;) {
BASE tmp = X[ix];
jx = ix + incX;
for (j = i + 1; j < N; j++) {
const BASE Aji = A[lda * j + i];
tmp -= Aji * X[jx];
jx += incX;
}
if (nonunit) {
X[ix] = tmp / A[lda * i + i];
} else {
X[ix] = tmp;
}
ix -= incX;
}
} else {
BLAS_ERROR("unrecognized operation");
}
}
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