Update to 2.0.0 tree from current Fremantle build

[opencv] / 3rdparty / lapack / dgelq2.c

diff --git a/3rdparty/lapack/dgelq2.c b/3rdparty/lapack/dgelq2.c
new file mode 100644 (file)
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+++ b/3rdparty/lapack/dgelq2.c
@@ -0,0 +1,144 @@
+#include "clapack.h"
+
+/* Subroutine */ int dgelq2_(integer *m, integer *n, doublereal *a, integer *
+       lda, doublereal *tau, doublereal *work, integer *info)
+{
+    /* System generated locals */
+    integer a_dim1, a_offset, i__1, i__2, i__3;
+
+    /* Local variables */
+    integer i__, k;
+    doublereal aii;
+    extern /* Subroutine */ int dlarf_(char *, integer *, integer *, 
+           doublereal *, integer *, doublereal *, doublereal *, integer *, 
+           doublereal *), dlarfg_(integer *, doublereal *, 
+           doublereal *, integer *, doublereal *), xerbla_(char *, integer *);
+
+
+/*  -- LAPACK routine (version 3.1) -- */
+/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/*     November 2006 */
+
+/*     .. Scalar Arguments .. */
+/*     .. */
+/*     .. Array Arguments .. */
+/*     .. */
+
+/*  Purpose */
+/*  ======= */
+
+/*  DGELQ2 computes an LQ factorization of a real m by n matrix A: */
+/*  A = L * Q. */
+
+/*  Arguments */
+/*  ========= */
+
+/*  M       (input) INTEGER */
+/*          The number of rows of the matrix A.  M >= 0. */
+
+/*  N       (input) INTEGER */
+/*          The number of columns of the matrix A.  N >= 0. */
+
+/*  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N) */
+/*          On entry, the m by n matrix A. */
+/*          On exit, the elements on and below the diagonal of the array */
+/*          contain the m by min(m,n) lower trapezoidal matrix L (L is */
+/*          lower triangular if m <= n); the elements above the diagonal, */
+/*          with the array TAU, represent the orthogonal matrix Q as a */
+/*          product of elementary reflectors (see Further Details). */
+
+/*  LDA     (input) INTEGER */
+/*          The leading dimension of the array A.  LDA >= max(1,M). */
+
+/*  TAU     (output) DOUBLE PRECISION array, dimension (min(M,N)) */
+/*          The scalar factors of the elementary reflectors (see Further */
+/*          Details). */
+
+/*  WORK    (workspace) DOUBLE PRECISION array, dimension (M) */
+
+/*  INFO    (output) INTEGER */
+/*          = 0: successful exit */
+/*          < 0: if INFO = -i, the i-th argument had an illegal value */
+
+/*  Further Details */
+/*  =============== */
+
+/*  The matrix Q is represented as a product of elementary reflectors */
+
+/*     Q = H(k) . . . H(2) H(1), where k = min(m,n). */
+
+/*  Each H(i) has the form */
+
+/*     H(i) = I - tau * v * v' */
+
+/*  where tau is a real scalar, and v is a real vector with */
+/*  v(1:i-1) = 0 and v(i) = 1; v(i+1:n) is stored on exit in A(i,i+1:n), */
+/*  and tau in TAU(i). */
+
+/*  ===================================================================== */
+
+/*     .. Parameters .. */
+/*     .. */
+/*     .. Local Scalars .. */
+/*     .. */
+/*     .. External Subroutines .. */
+/*     .. */
+/*     .. Intrinsic Functions .. */
+/*     .. */
+/*     .. Executable Statements .. */
+
+/*     Test the input arguments */
+
+    /* Parameter adjustments */
+    a_dim1 = *lda;
+    a_offset = 1 + a_dim1;
+    a -= a_offset;
+    --tau;
+    --work;
+
+    /* Function Body */
+    *info = 0;
+    if (*m < 0) {
+       *info = -1;
+    } else if (*n < 0) {
+       *info = -2;
+    } else if (*lda < max(1,*m)) {
+       *info = -4;
+    }
+    if (*info != 0) {
+       i__1 = -(*info);
+       xerbla_("DGELQ2", &i__1);
+       return 0;
+    }
+
+    k = min(*m,*n);
+
+    i__1 = k;
+    for (i__ = 1; i__ <= i__1; ++i__) {
+
+/*        Generate elementary reflector H(i) to annihilate A(i,i+1:n) */
+
+       i__2 = *n - i__ + 1;
+/* Computing MIN */
+       i__3 = i__ + 1;
+       dlarfg_(&i__2, &a[i__ + i__ * a_dim1], &a[i__ + min(i__3, *n)* a_dim1]
+, lda, &tau[i__]);
+       if (i__ < *m) {
+
+/*           Apply H(i) to A(i+1:m,i:n) from the right */
+
+           aii = a[i__ + i__ * a_dim1];
+           a[i__ + i__ * a_dim1] = 1.;
+           i__2 = *m - i__;
+           i__3 = *n - i__ + 1;
+           dlarf_("Right", &i__2, &i__3, &a[i__ + i__ * a_dim1], lda, &tau[
+                   i__], &a[i__ + 1 + i__ * a_dim1], lda, &work[1]);
+           a[i__ + i__ * a_dim1] = aii;
+       }
+/* L10: */
+    }
+    return 0;
+
+/*     End of DGELQ2 */
+
+} /* dgelq2_ */