--- /dev/null
+#include "clapack.h"
+
+/* Subroutine */ int ssyr2k_(char *uplo, char *trans, integer *n, integer *k,
+ real *alpha, real *a, integer *lda, real *b, integer *ldb, real *beta,
+ real *c__, integer *ldc)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, b_dim1, b_offset, c_dim1, c_offset, i__1, i__2,
+ i__3;
+
+ /* Local variables */
+ integer i__, j, l, info;
+ real temp1, temp2;
+ extern logical lsame_(char *, char *);
+ integer nrowa;
+ logical upper;
+ extern /* Subroutine */ int xerbla_(char *, integer *);
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* SSYR2K performs one of the symmetric rank 2k operations */
+
+/* C := alpha*A*B' + alpha*B*A' + beta*C, */
+
+/* or */
+
+/* C := alpha*A'*B + alpha*B'*A + beta*C, */
+
+/* where alpha and beta are scalars, C is an n by n symmetric matrix */
+/* and A and B are n by k matrices in the first case and k by n */
+/* matrices 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*B' + alpha*B*A' + */
+/* beta*C. */
+
+/* TRANS = 'T' or 't' C := alpha*A'*B + alpha*B'*A + */
+/* beta*C. */
+
+/* TRANS = 'C' or 'c' C := alpha*A'*B + alpha*B'*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 matrices A and B, and on entry with */
+/* TRANS = 'T' or 't' or 'C' or 'c', K specifies the number */
+/* of rows of the matrices A and B. 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. */
+
+/* B - REAL array of DIMENSION ( LDB, kb ), where kb 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 B must contain the matrix B, otherwise */
+/* the leading k by n part of the array B must contain the */
+/* matrix B. */
+/* Unchanged on exit. */
+
+/* LDB - INTEGER. */
+/* On entry, LDB specifies the first dimension of B as declared */
+/* in the calling (sub) program. When TRANS = 'N' or 'n' */
+/* then LDB must be at least max( 1, n ), otherwise LDB 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;
+ b_dim1 = *ldb;
+ b_offset = 1 + b_dim1;
+ b -= b_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 (*ldb < max(1,nrowa)) {
+ info = 9;
+ } else if (*ldc < max(1,*n)) {
+ info = 12;
+ }
+ if (info != 0) {
+ xerbla_("SSYR2K", &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*B' + alpha*B*A' + 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 || b[j + l * b_dim1] != 0.f)
+ {
+ temp1 = *alpha * b[j + l * b_dim1];
+ temp2 = *alpha * a[j + l * a_dim1];
+ i__3 = j;
+ for (i__ = 1; i__ <= i__3; ++i__) {
+ c__[i__ + j * c_dim1] = c__[i__ + j * c_dim1] + a[
+ i__ + l * a_dim1] * temp1 + b[i__ + l *
+ b_dim1] * temp2;
+/* 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 || b[j + l * b_dim1] != 0.f)
+ {
+ temp1 = *alpha * b[j + l * b_dim1];
+ temp2 = *alpha * a[j + l * a_dim1];
+ i__3 = *n;
+ for (i__ = j; i__ <= i__3; ++i__) {
+ c__[i__ + j * c_dim1] = c__[i__ + j * c_dim1] + a[
+ i__ + l * a_dim1] * temp1 + b[i__ + l *
+ b_dim1] * temp2;
+/* L160: */
+ }
+ }
+/* L170: */
+ }
+/* L180: */
+ }
+ }
+ } else {
+
+/* Form C := alpha*A'*B + alpha*B'*A + C. */
+
+ if (upper) {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ i__2 = j;
+ for (i__ = 1; i__ <= i__2; ++i__) {
+ temp1 = 0.f;
+ temp2 = 0.f;
+ i__3 = *k;
+ for (l = 1; l <= i__3; ++l) {
+ temp1 += a[l + i__ * a_dim1] * b[l + j * b_dim1];
+ temp2 += b[l + i__ * b_dim1] * a[l + j * a_dim1];
+/* L190: */
+ }
+ if (*beta == 0.f) {
+ c__[i__ + j * c_dim1] = *alpha * temp1 + *alpha *
+ temp2;
+ } else {
+ c__[i__ + j * c_dim1] = *beta * c__[i__ + j * c_dim1]
+ + *alpha * temp1 + *alpha * temp2;
+ }
+/* L200: */
+ }
+/* L210: */
+ }
+ } else {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ i__2 = *n;
+ for (i__ = j; i__ <= i__2; ++i__) {
+ temp1 = 0.f;
+ temp2 = 0.f;
+ i__3 = *k;
+ for (l = 1; l <= i__3; ++l) {
+ temp1 += a[l + i__ * a_dim1] * b[l + j * b_dim1];
+ temp2 += b[l + i__ * b_dim1] * a[l + j * a_dim1];
+/* L220: */
+ }
+ if (*beta == 0.f) {
+ c__[i__ + j * c_dim1] = *alpha * temp1 + *alpha *
+ temp2;
+ } else {
+ c__[i__ + j * c_dim1] = *beta * c__[i__ + j * c_dim1]
+ + *alpha * temp1 + *alpha * temp2;
+ }
+/* L230: */
+ }
+/* L240: */
+ }
+ }
+ }
+
+ return 0;
+
+/* End of SSYR2K. */
+
+} /* ssyr2k_ */
projects / opencv / blobdiff