--- /dev/null
+#include "clapack.h"
+
+/* Table of constant values */
+
+static integer c__1 = 1;
+
+doublereal slansy_(char *norm, char *uplo, integer *n, real *a, integer *lda,
+ real *work)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, i__1, i__2;
+ real ret_val, r__1, r__2, r__3;
+
+ /* Builtin functions */
+ double sqrt(doublereal);
+
+ /* Local variables */
+ integer i__, j;
+ real sum, absa, scale;
+ extern logical lsame_(char *, char *);
+ real value;
+ extern /* Subroutine */ int slassq_(integer *, real *, integer *, real *,
+ real *);
+
+
+/* -- LAPACK auxiliary routine (version 3.1) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* SLANSY returns the value of the one norm, or the Frobenius norm, or */
+/* the infinity norm, or the element of largest absolute value of a */
+/* real symmetric matrix A. */
+
+/* Description */
+/* =========== */
+
+/* SLANSY returns the value */
+
+/* SLANSY = ( max(abs(A(i,j))), NORM = 'M' or 'm' */
+/* ( */
+/* ( norm1(A), NORM = '1', 'O' or 'o' */
+/* ( */
+/* ( normI(A), NORM = 'I' or 'i' */
+/* ( */
+/* ( normF(A), NORM = 'F', 'f', 'E' or 'e' */
+
+/* where norm1 denotes the one norm of a matrix (maximum column sum), */
+/* normI denotes the infinity norm of a matrix (maximum row sum) and */
+/* normF denotes the Frobenius norm of a matrix (square root of sum of */
+/* squares). Note that max(abs(A(i,j))) is not a consistent matrix norm. */
+
+/* Arguments */
+/* ========= */
+
+/* NORM (input) CHARACTER*1 */
+/* Specifies the value to be returned in SLANSY as described */
+/* above. */
+
+/* UPLO (input) CHARACTER*1 */
+/* Specifies whether the upper or lower triangular part of the */
+/* symmetric matrix A is to be referenced. */
+/* = 'U': Upper triangular part of A is referenced */
+/* = 'L': Lower triangular part of A is referenced */
+
+/* N (input) INTEGER */
+/* The order of the matrix A. N >= 0. When N = 0, SLANSY is */
+/* set to zero. */
+
+/* A (input) REAL array, dimension (LDA,N) */
+/* The symmetric matrix A. If UPLO = 'U', the leading n by n */
+/* upper triangular part of A contains the upper triangular part */
+/* of the matrix A, and the strictly lower triangular part of A */
+/* is not referenced. If UPLO = 'L', the leading n by n lower */
+/* triangular part of A contains the lower triangular part of */
+/* the matrix A, and the strictly upper triangular part of A is */
+/* not referenced. */
+
+/* LDA (input) INTEGER */
+/* The leading dimension of the array A. LDA >= max(N,1). */
+
+/* WORK (workspace) REAL array, dimension (MAX(1,LWORK)), */
+/* where LWORK >= N when NORM = 'I' or '1' or 'O'; otherwise, */
+/* WORK is not referenced. */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. External Functions .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+ /* Parameter adjustments */
+ a_dim1 = *lda;
+ a_offset = 1 + a_dim1;
+ a -= a_offset;
+ --work;
+
+ /* Function Body */
+ if (*n == 0) {
+ value = 0.f;
+ } else if (lsame_(norm, "M")) {
+
+/* Find max(abs(A(i,j))). */
+
+ value = 0.f;
+ if (lsame_(uplo, "U")) {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ i__2 = j;
+ for (i__ = 1; i__ <= i__2; ++i__) {
+/* Computing MAX */
+ r__2 = value, r__3 = (r__1 = a[i__ + j * a_dim1], dabs(
+ r__1));
+ value = dmax(r__2,r__3);
+/* L10: */
+ }
+/* L20: */
+ }
+ } else {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ i__2 = *n;
+ for (i__ = j; i__ <= i__2; ++i__) {
+/* Computing MAX */
+ r__2 = value, r__3 = (r__1 = a[i__ + j * a_dim1], dabs(
+ r__1));
+ value = dmax(r__2,r__3);
+/* L30: */
+ }
+/* L40: */
+ }
+ }
+ } else if (lsame_(norm, "I") || lsame_(norm, "O") || *(unsigned char *)norm == '1') {
+
+/* Find normI(A) ( = norm1(A), since A is symmetric). */
+
+ value = 0.f;
+ if (lsame_(uplo, "U")) {
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ sum = 0.f;
+ i__2 = j - 1;
+ for (i__ = 1; i__ <= i__2; ++i__) {
+ absa = (r__1 = a[i__ + j * a_dim1], dabs(r__1));
+ sum += absa;
+ work[i__] += absa;
+/* L50: */
+ }
+ work[j] = sum + (r__1 = a[j + j * a_dim1], dabs(r__1));
+/* L60: */
+ }
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+/* Computing MAX */
+ r__1 = value, r__2 = work[i__];
+ value = dmax(r__1,r__2);
+/* L70: */
+ }
+ } else {
+ i__1 = *n;
+ for (i__ = 1; i__ <= i__1; ++i__) {
+ work[i__] = 0.f;
+/* L80: */
+ }
+ i__1 = *n;
+ for (j = 1; j <= i__1; ++j) {
+ sum = work[j] + (r__1 = a[j + j * a_dim1], dabs(r__1));
+ i__2 = *n;
+ for (i__ = j + 1; i__ <= i__2; ++i__) {
+ absa = (r__1 = a[i__ + j * a_dim1], dabs(r__1));
+ sum += absa;
+ work[i__] += absa;
+/* L90: */
+ }
+ value = dmax(value,sum);
+/* L100: */
+ }
+ }
+ } else if (lsame_(norm, "F") || lsame_(norm, "E")) {
+
+/* Find normF(A). */
+
+ scale = 0.f;
+ sum = 1.f;
+ if (lsame_(uplo, "U")) {
+ i__1 = *n;
+ for (j = 2; j <= i__1; ++j) {
+ i__2 = j - 1;
+ slassq_(&i__2, &a[j * a_dim1 + 1], &c__1, &scale, &sum);
+/* L110: */
+ }
+ } else {
+ i__1 = *n - 1;
+ for (j = 1; j <= i__1; ++j) {
+ i__2 = *n - j;
+ slassq_(&i__2, &a[j + 1 + j * a_dim1], &c__1, &scale, &sum);
+/* L120: */
+ }
+ }
+ sum *= 2;
+ i__1 = *lda + 1;
+ slassq_(n, &a[a_offset], &i__1, &scale, &sum);
+ value = scale * sqrt(sum);
+ }
+
+ ret_val = value;
+ return ret_val;
+
+/* End of SLANSY */
+
+} /* slansy_ */
projects / opencv / blobdiff