--- /dev/null
+#include "clapack.h"
+
+/* Table of constant values */
+
+static integer c__1 = 1;
+static integer c_n1 = -1;
+static doublereal c_b13 = -1.;
+static doublereal c_b14 = 1.;
+
+/* Subroutine */ int dpotrf_(char *uplo, integer *n, doublereal *a, integer *
+ lda, integer *info)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, i__1, i__2, i__3, i__4;
+
+ /* Local variables */
+ integer j, jb, nb;
+ extern /* Subroutine */ int dgemm_(char *, char *, integer *, integer *,
+ integer *, doublereal *, doublereal *, integer *, doublereal *,
+ integer *, doublereal *, doublereal *, integer *);
+ extern logical lsame_(char *, char *);
+ extern /* Subroutine */ int dtrsm_(char *, char *, char *, char *,
+ integer *, integer *, doublereal *, doublereal *, integer *,
+ doublereal *, integer *);
+ logical upper;
+ extern /* Subroutine */ int dsyrk_(char *, char *, integer *, integer *,
+ doublereal *, doublereal *, integer *, doublereal *, doublereal *,
+ integer *), dpotf2_(char *, integer *,
+ doublereal *, integer *, integer *), xerbla_(char *,
+ integer *);
+ extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
+ integer *, integer *);
+
+
+/* -- LAPACK routine (version 3.1) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* DPOTRF computes the Cholesky factorization of a real symmetric */
+/* positive definite matrix A. */
+
+/* The factorization has the form */
+/* A = U**T * U, if UPLO = 'U', or */
+/* A = L * L**T, if UPLO = 'L', */
+/* where U is an upper triangular matrix and L is lower triangular. */
+
+/* This is the block version of the algorithm, calling Level 3 BLAS. */
+
+/* Arguments */
+/* ========= */
+
+/* UPLO (input) CHARACTER*1 */
+/* = 'U': Upper triangle of A is stored; */
+/* = 'L': Lower triangle of A is stored. */
+
+/* N (input) INTEGER */
+/* The order of the matrix A. N >= 0. */
+
+/* A (input/output) DOUBLE PRECISION array, dimension (LDA,N) */
+/* On entry, 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. */
+
+/* On exit, if INFO = 0, the factor U or L from the Cholesky */
+/* factorization A = U**T*U or A = L*L**T. */
+
+/* LDA (input) INTEGER */
+/* The leading dimension of the array A. LDA >= max(1,N). */
+
+/* INFO (output) INTEGER */
+/* = 0: successful exit */
+/* < 0: if INFO = -i, the i-th argument had an illegal value */
+/* > 0: if INFO = i, the leading minor of order i is not */
+/* positive definite, and the factorization could not be */
+/* completed. */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Functions .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+/* Test the input parameters. */
+
+ /* Parameter adjustments */
+ a_dim1 = *lda;
+ a_offset = 1 + a_dim1;
+ a -= a_offset;
+
+ /* Function Body */
+ *info = 0;
+ upper = lsame_(uplo, "U");
+ if (! upper && ! lsame_(uplo, "L")) {
+ *info = -1;
+ } else if (*n < 0) {
+ *info = -2;
+ } else if (*lda < max(1,*n)) {
+ *info = -4;
+ }
+ if (*info != 0) {
+ i__1 = -(*info);
+ xerbla_("DPOTRF", &i__1);
+ return 0;
+ }
+
+/* Quick return if possible */
+
+ if (*n == 0) {
+ return 0;
+ }
+
+/* Determine the block size for this environment. */
+
+ nb = ilaenv_(&c__1, "DPOTRF", uplo, n, &c_n1, &c_n1, &c_n1);
+ if (nb <= 1 || nb >= *n) {
+
+/* Use unblocked code. */
+
+ dpotf2_(uplo, n, &a[a_offset], lda, info);
+ } else {
+
+/* Use blocked code. */
+
+ if (upper) {
+
+/* Compute the Cholesky factorization A = U'*U. */
+
+ i__1 = *n;
+ i__2 = nb;
+ for (j = 1; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) {
+
+/* Update and factorize the current diagonal block and test */
+/* for non-positive-definiteness. */
+
+/* Computing MIN */
+ i__3 = nb, i__4 = *n - j + 1;
+ jb = min(i__3,i__4);
+ i__3 = j - 1;
+ dsyrk_("Upper", "Transpose", &jb, &i__3, &c_b13, &a[j *
+ a_dim1 + 1], lda, &c_b14, &a[j + j * a_dim1], lda);
+ dpotf2_("Upper", &jb, &a[j + j * a_dim1], lda, info);
+ if (*info != 0) {
+ goto L30;
+ }
+ if (j + jb <= *n) {
+
+/* Compute the current block row. */
+
+ i__3 = *n - j - jb + 1;
+ i__4 = j - 1;
+ dgemm_("Transpose", "No transpose", &jb, &i__3, &i__4, &
+ c_b13, &a[j * a_dim1 + 1], lda, &a[(j + jb) *
+ a_dim1 + 1], lda, &c_b14, &a[j + (j + jb) *
+ a_dim1], lda);
+ i__3 = *n - j - jb + 1;
+ dtrsm_("Left", "Upper", "Transpose", "Non-unit", &jb, &
+ i__3, &c_b14, &a[j + j * a_dim1], lda, &a[j + (j
+ + jb) * a_dim1], lda);
+ }
+/* L10: */
+ }
+
+ } else {
+
+/* Compute the Cholesky factorization A = L*L'. */
+
+ i__2 = *n;
+ i__1 = nb;
+ for (j = 1; i__1 < 0 ? j >= i__2 : j <= i__2; j += i__1) {
+
+/* Update and factorize the current diagonal block and test */
+/* for non-positive-definiteness. */
+
+/* Computing MIN */
+ i__3 = nb, i__4 = *n - j + 1;
+ jb = min(i__3,i__4);
+ i__3 = j - 1;
+ dsyrk_("Lower", "No transpose", &jb, &i__3, &c_b13, &a[j +
+ a_dim1], lda, &c_b14, &a[j + j * a_dim1], lda);
+ dpotf2_("Lower", &jb, &a[j + j * a_dim1], lda, info);
+ if (*info != 0) {
+ goto L30;
+ }
+ if (j + jb <= *n) {
+
+/* Compute the current block column. */
+
+ i__3 = *n - j - jb + 1;
+ i__4 = j - 1;
+ dgemm_("No transpose", "Transpose", &i__3, &jb, &i__4, &
+ c_b13, &a[j + jb + a_dim1], lda, &a[j + a_dim1],
+ lda, &c_b14, &a[j + jb + j * a_dim1], lda);
+ i__3 = *n - j - jb + 1;
+ dtrsm_("Right", "Lower", "Transpose", "Non-unit", &i__3, &
+ jb, &c_b14, &a[j + j * a_dim1], lda, &a[j + jb +
+ j * a_dim1], lda);
+ }
+/* L20: */
+ }
+ }
+ }
+ goto L40;
+
+L30:
+ *info = *info + j - 1;
+
+L40:
+ return 0;
+
+/* End of DPOTRF */
+
+} /* dpotrf_ */
projects / opencv / blobdiff