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opencv/3rdparty/lapack/dtrmv.c

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#include "clapack.h"
/* Subroutine */ int dtrmv_(char *uplo, char *trans, char *diag, integer *n,
doublereal *a, integer *lda, doublereal *x, integer *incx)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
/* Local variables */
integer i__, j, ix, jx, kx, info;
doublereal temp;
extern logical lsame_(char *, char *);
extern /* Subroutine */ int xerbla_(char *, integer *);
logical nounit;
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* DTRMV performs one of the matrix-vector operations */
/* x := A*x, or x := A'*x, */
/* where x is an n element vector and A is an n by n unit, or non-unit, */
/* upper or lower triangular matrix. */
/* Arguments */
/* ========== */
/* UPLO - CHARACTER*1. */
/* On entry, UPLO specifies whether the matrix is an upper or */
/* lower triangular matrix as follows: */
/* UPLO = 'U' or 'u' A is an upper triangular matrix. */
/* UPLO = 'L' or 'l' A is a lower triangular matrix. */
/* Unchanged on exit. */
/* TRANS - CHARACTER*1. */
/* On entry, TRANS specifies the operation to be performed as */
/* follows: */
/* TRANS = 'N' or 'n' x := A*x. */
/* TRANS = 'T' or 't' x := A'*x. */
/* TRANS = 'C' or 'c' x := A'*x. */
/* Unchanged on exit. */
/* DIAG - CHARACTER*1. */
/* On entry, DIAG specifies whether or not A is unit */
/* triangular as follows: */
/* DIAG = 'U' or 'u' A is assumed to be unit triangular. */
/* DIAG = 'N' or 'n' A is not assumed to be unit */
/* triangular. */
/* Unchanged on exit. */
/* N - INTEGER. */
/* On entry, N specifies the order of the matrix A. */
/* N must be at least zero. */
/* Unchanged on exit. */
/* A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). */
/* Before entry with UPLO = 'U' or 'u', the leading n by n */
/* upper triangular part of the array A must contain the upper */
/* triangular matrix and the strictly lower triangular part of */
/* A is not referenced. */
/* Before entry with UPLO = 'L' or 'l', the leading n by n */
/* lower triangular part of the array A must contain the lower */
/* triangular matrix and the strictly upper triangular part of */
/* A is not referenced. */
/* Note that when DIAG = 'U' or 'u', the diagonal elements of */
/* A are not referenced either, but are assumed to be unity. */
/* Unchanged on exit. */
/* LDA - INTEGER. */
/* On entry, LDA specifies the first dimension of A as declared */
/* in the calling (sub) program. LDA must be at least */
/* max( 1, n ). */
/* Unchanged on exit. */
/* X - DOUBLE PRECISION array of dimension at least */
/* ( 1 + ( n - 1 )*abs( INCX ) ). */
/* Before entry, the incremented array X must contain the n */
/* element vector x. On exit, X is overwritten with the */
/* tranformed vector x. */
/* INCX - INTEGER. */
/* On entry, INCX specifies the increment for the elements of */
/* X. INCX must not be zero. */
/* Unchanged on exit. */
/* Level 2 Blas routine. */
/* -- Written on 22-October-1986. */
/* Jack Dongarra, Argonne National Lab. */
/* Jeremy Du Croz, Nag Central Office. */
/* Sven Hammarling, Nag Central Office. */
/* Richard Hanson, Sandia National Labs. */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--x;
/* Function Body */
info = 0;
if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
info = 1;
} else if (! lsame_(trans, "N") && ! lsame_(trans,
"T") && ! lsame_(trans, "C")) {
info = 2;
} else if (! lsame_(diag, "U") && ! lsame_(diag,
"N")) {
info = 3;
} else if (*n < 0) {
info = 4;
} else if (*lda < max(1,*n)) {
info = 6;
} else if (*incx == 0) {
info = 8;
}
if (info != 0) {
xerbla_("DTRMV ", &info);
return 0;
}
/* Quick return if possible. */
if (*n == 0) {
return 0;
}
nounit = lsame_(diag, "N");
/* Set up the start point in X if the increment is not unity. This */
/* will be ( N - 1 )*INCX too small for descending loops. */
if (*incx <= 0) {
kx = 1 - (*n - 1) * *incx;
} else if (*incx != 1) {
kx = 1;
}
/* Start the operations. In this version the elements of A are */
/* accessed sequentially with one pass through A. */
if (lsame_(trans, "N")) {
/* Form x := A*x. */
if (lsame_(uplo, "U")) {
if (*incx == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (x[j] != 0.) {
temp = x[j];
i__2 = j - 1;
for (i__ = 1; i__ <= i__2; ++i__) {
x[i__] += temp * a[i__ + j * a_dim1];
/* L10: */
}
if (nounit) {
x[j] *= a[j + j * a_dim1];
}
}
/* L20: */
}
} else {
jx = kx;
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (x[jx] != 0.) {
temp = x[jx];
ix = kx;
i__2 = j - 1;
for (i__ = 1; i__ <= i__2; ++i__) {
x[ix] += temp * a[i__ + j * a_dim1];
ix += *incx;
/* L30: */
}
if (nounit) {
x[jx] *= a[j + j * a_dim1];
}
}
jx += *incx;
/* L40: */
}
}
} else {
if (*incx == 1) {
for (j = *n; j >= 1; --j) {
if (x[j] != 0.) {
temp = x[j];
i__1 = j + 1;
for (i__ = *n; i__ >= i__1; --i__) {
x[i__] += temp * a[i__ + j * a_dim1];
/* L50: */
}
if (nounit) {
x[j] *= a[j + j * a_dim1];
}
}
/* L60: */
}
} else {
kx += (*n - 1) * *incx;
jx = kx;
for (j = *n; j >= 1; --j) {
if (x[jx] != 0.) {
temp = x[jx];
ix = kx;
i__1 = j + 1;
for (i__ = *n; i__ >= i__1; --i__) {
x[ix] += temp * a[i__ + j * a_dim1];
ix -= *incx;
/* L70: */
}
if (nounit) {
x[jx] *= a[j + j * a_dim1];
}
}
jx -= *incx;
/* L80: */
}
}
}
} else {
/* Form x := A'*x. */
if (lsame_(uplo, "U")) {
if (*incx == 1) {
for (j = *n; j >= 1; --j) {
temp = x[j];
if (nounit) {
temp *= a[j + j * a_dim1];
}
for (i__ = j - 1; i__ >= 1; --i__) {
temp += a[i__ + j * a_dim1] * x[i__];
/* L90: */
}
x[j] = temp;
/* L100: */
}
} else {
jx = kx + (*n - 1) * *incx;
for (j = *n; j >= 1; --j) {
temp = x[jx];
ix = jx;
if (nounit) {
temp *= a[j + j * a_dim1];
}
for (i__ = j - 1; i__ >= 1; --i__) {
ix -= *incx;
temp += a[i__ + j * a_dim1] * x[ix];
/* L110: */
}
x[jx] = temp;
jx -= *incx;
/* L120: */
}
}
} else {
if (*incx == 1) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
temp = x[j];
if (nounit) {
temp *= a[j + j * a_dim1];
}
i__2 = *n;
for (i__ = j + 1; i__ <= i__2; ++i__) {
temp += a[i__ + j * a_dim1] * x[i__];
/* L130: */
}
x[j] = temp;
/* L140: */
}
} else {
jx = kx;
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
temp = x[jx];
ix = jx;
if (nounit) {
temp *= a[j + j * a_dim1];
}
i__2 = *n;
for (i__ = j + 1; i__ <= i__2; ++i__) {
ix += *incx;
temp += a[i__ + j * a_dim1] * x[ix];
/* L150: */
}
x[jx] = temp;
jx += *incx;
/* L160: */
}
}
}
}
return 0;
/* End of DTRMV . */
} /* dtrmv_ */
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