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opencv/3rdparty/lapack/ssyrk.c

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#include "clapack.h"
/* Subroutine */ int ssyrk_(char *uplo, char *trans, integer *n, integer *k,
real *alpha, real *a, integer *lda, real *beta, real *c__, integer *
ldc)
{
/* System generated locals */
integer a_dim1, a_offset, c_dim1, c_offset, i__1, i__2, i__3;
/* Local variables */
integer i__, j, l, info;
real temp;
extern logical lsame_(char *, char *);
integer nrowa;
logical upper;
extern /* Subroutine */ int xerbla_(char *, integer *);
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SSYRK performs one of the symmetric rank k operations */
/* C := alpha*A*A' + beta*C, */
/* or */
/* C := alpha*A'*A + beta*C, */
/* where alpha and beta are scalars, C is an n by n symmetric matrix */
/* and A is an n by k matrix in the first case and a k by n matrix */
/* in the second case. */
/* Arguments */
/* ========== */
/* UPLO - CHARACTER*1. */
/* On entry, UPLO specifies whether the upper or lower */
/* triangular part of the array C is to be referenced as */
/* follows: */
/* UPLO = 'U' or 'u' Only the upper triangular part of C */
/* is to be referenced. */
/* UPLO = 'L' or 'l' Only the lower triangular part of C */
/* is to be referenced. */
/* Unchanged on exit. */
/* TRANS - CHARACTER*1. */
/* On entry, TRANS specifies the operation to be performed as */
/* follows: */
/* TRANS = 'N' or 'n' C := alpha*A*A' + beta*C. */
/* TRANS = 'T' or 't' C := alpha*A'*A + beta*C. */
/* TRANS = 'C' or 'c' C := alpha*A'*A + beta*C. */
/* Unchanged on exit. */
/* N - INTEGER. */
/* On entry, N specifies the order of the matrix C. N must be */
/* at least zero. */
/* Unchanged on exit. */
/* K - INTEGER. */
/* On entry with TRANS = 'N' or 'n', K specifies the number */
/* of columns of the matrix A, and on entry with */
/* TRANS = 'T' or 't' or 'C' or 'c', K specifies the number */
/* of rows of the matrix A. K must be at least zero. */
/* Unchanged on exit. */
/* ALPHA - REAL . */
/* On entry, ALPHA specifies the scalar alpha. */
/* Unchanged on exit. */
/* A - REAL array of DIMENSION ( LDA, ka ), where ka is */
/* k when TRANS = 'N' or 'n', and is n otherwise. */
/* Before entry with TRANS = 'N' or 'n', the leading n by k */
/* part of the array A must contain the matrix A, otherwise */
/* the leading k by n part of the array A must contain the */
/* matrix A. */
/* Unchanged on exit. */
/* LDA - INTEGER. */
/* On entry, LDA specifies the first dimension of A as declared */
/* in the calling (sub) program. When TRANS = 'N' or 'n' */
/* then LDA must be at least max( 1, n ), otherwise LDA must */
/* be at least max( 1, k ). */
/* Unchanged on exit. */
/* BETA - REAL . */
/* On entry, BETA specifies the scalar beta. */
/* Unchanged on exit. */
/* C - REAL array of DIMENSION ( LDC, n ). */
/* Before entry with UPLO = 'U' or 'u', the leading n by n */
/* upper triangular part of the array C must contain the upper */
/* triangular part of the symmetric matrix and the strictly */
/* lower triangular part of C is not referenced. On exit, the */
/* upper triangular part of the array C is overwritten by the */
/* upper triangular part of the updated matrix. */
/* Before entry with UPLO = 'L' or 'l', the leading n by n */
/* lower triangular part of the array C must contain the lower */
/* triangular part of the symmetric matrix and the strictly */
/* upper triangular part of C is not referenced. On exit, the */
/* lower triangular part of the array C is overwritten by the */
/* lower triangular part of the updated matrix. */
/* LDC - INTEGER. */
/* On entry, LDC specifies the first dimension of C as declared */
/* in the calling (sub) program. LDC must be at least */
/* max( 1, n ). */
/* Unchanged on exit. */
/* Level 3 Blas routine. */
/* -- Written on 8-February-1989. */
/* Jack Dongarra, Argonne National Laboratory. */
/* Iain Duff, AERE Harwell. */
/* Jeremy Du Croz, Numerical Algorithms Group Ltd. */
/* Sven Hammarling, Numerical Algorithms Group Ltd. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. Parameters .. */
/* .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
c_dim1 = *ldc;
c_offset = 1 + c_dim1;
c__ -= c_offset;
/* Function Body */
if (lsame_(trans, "N")) {
nrowa = *n;
} else {
nrowa = *k;
}
upper = lsame_(uplo, "U");
info = 0;
if (! upper && ! lsame_(uplo, "L")) {
info = 1;
} else if (! lsame_(trans, "N") && ! lsame_(trans,
"T") && ! lsame_(trans, "C")) {
info = 2;
} else if (*n < 0) {
info = 3;
} else if (*k < 0) {
info = 4;
} else if (*lda < max(1,nrowa)) {
info = 7;
} else if (*ldc < max(1,*n)) {
info = 10;
}
if (info != 0) {
xerbla_("SSYRK ", &info);
return 0;
}
/* Quick return if possible. */
if (*n == 0 || (*alpha == 0.f || *k == 0) && *beta == 1.f) {
return 0;
}
/* And when alpha.eq.zero. */
if (*alpha == 0.f) {
if (upper) {
if (*beta == 0.f) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = 0.f;
/* L10: */
}
/* L20: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = *beta * c__[i__ + j * c_dim1];
/* L30: */
}
/* L40: */
}
}
} else {
if (*beta == 0.f) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = 0.f;
/* L50: */
}
/* L60: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = *beta * c__[i__ + j * c_dim1];
/* L70: */
}
/* L80: */
}
}
}
return 0;
}
/* Start the operations. */
if (lsame_(trans, "N")) {
/* Form C := alpha*A*A' + beta*C. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (*beta == 0.f) {
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = 0.f;
/* L90: */
}
} else if (*beta != 1.f) {
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = *beta * c__[i__ + j * c_dim1];
/* L100: */
}
}
i__2 = *k;
for (l = 1; l <= i__2; ++l) {
if (a[j + l * a_dim1] != 0.f) {
temp = *alpha * a[j + l * a_dim1];
i__3 = j;
for (i__ = 1; i__ <= i__3; ++i__) {
c__[i__ + j * c_dim1] += temp * a[i__ + l *
a_dim1];
/* L110: */
}
}
/* L120: */
}
/* L130: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (*beta == 0.f) {
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = 0.f;
/* L140: */
}
} else if (*beta != 1.f) {
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
c__[i__ + j * c_dim1] = *beta * c__[i__ + j * c_dim1];
/* L150: */
}
}
i__2 = *k;
for (l = 1; l <= i__2; ++l) {
if (a[j + l * a_dim1] != 0.f) {
temp = *alpha * a[j + l * a_dim1];
i__3 = *n;
for (i__ = j; i__ <= i__3; ++i__) {
c__[i__ + j * c_dim1] += temp * a[i__ + l *
a_dim1];
/* L160: */
}
}
/* L170: */
}
/* L180: */
}
}
} else {
/* Form C := alpha*A'*A + beta*C. */
if (upper) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = j;
for (i__ = 1; i__ <= i__2; ++i__) {
temp = 0.f;
i__3 = *k;
for (l = 1; l <= i__3; ++l) {
temp += a[l + i__ * a_dim1] * a[l + j * a_dim1];
/* L190: */
}
if (*beta == 0.f) {
c__[i__ + j * c_dim1] = *alpha * temp;
} else {
c__[i__ + j * c_dim1] = *alpha * temp + *beta * c__[
i__ + j * c_dim1];
}
/* L200: */
}
/* L210: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *n;
for (i__ = j; i__ <= i__2; ++i__) {
temp = 0.f;
i__3 = *k;
for (l = 1; l <= i__3; ++l) {
temp += a[l + i__ * a_dim1] * a[l + j * a_dim1];
/* L220: */
}
if (*beta == 0.f) {
c__[i__ + j * c_dim1] = *alpha * temp;
} else {
c__[i__ + j * c_dim1] = *alpha * temp + *beta * c__[
i__ + j * c_dim1];
}
/* L230: */
}
/* L240: */
}
}
}
return 0;
/* End of SSYRK . */
} /* ssyrk_ */
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