mirror of https://github.com/opencv/opencv.git
Open Source Computer Vision Library
https://opencv.org/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
252 lines
7.1 KiB
252 lines
7.1 KiB
/* dgeqrf.f -- translated by f2c (version 20061008). |
|
You must link the resulting object file with libf2c: |
|
on Microsoft Windows system, link with libf2c.lib; |
|
on Linux or Unix systems, link with .../path/to/libf2c.a -lm |
|
or, if you install libf2c.a in a standard place, with -lf2c -lm |
|
-- in that order, at the end of the command line, as in |
|
cc *.o -lf2c -lm |
|
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., |
|
|
|
http://www.netlib.org/f2c/libf2c.zip |
|
*/ |
|
|
|
#include "clapack.h" |
|
|
|
|
|
/* Table of constant values */ |
|
|
|
static integer c__1 = 1; |
|
static integer c_n1 = -1; |
|
static integer c__3 = 3; |
|
static integer c__2 = 2; |
|
|
|
/* Subroutine */ int dgeqrf_(integer *m, integer *n, doublereal *a, integer * |
|
lda, doublereal *tau, doublereal *work, integer *lwork, integer *info) |
|
{ |
|
/* System generated locals */ |
|
integer a_dim1, a_offset, i__1, i__2, i__3, i__4; |
|
|
|
/* Local variables */ |
|
integer i__, k, ib, nb, nx, iws, nbmin, iinfo; |
|
extern /* Subroutine */ int dgeqr2_(integer *, integer *, doublereal *, |
|
integer *, doublereal *, doublereal *, integer *), dlarfb_(char *, |
|
char *, char *, char *, integer *, integer *, integer *, |
|
doublereal *, integer *, doublereal *, integer *, doublereal *, |
|
integer *, doublereal *, integer *), dlarft_(char *, char *, integer *, integer *, doublereal |
|
*, integer *, doublereal *, doublereal *, integer *), xerbla_(char *, integer *); |
|
extern integer ilaenv_(integer *, char *, char *, integer *, integer *, |
|
integer *, integer *); |
|
integer ldwork, lwkopt; |
|
logical lquery; |
|
|
|
|
|
/* -- LAPACK routine (version 3.2) -- */ |
|
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */ |
|
/* November 2006 */ |
|
|
|
/* .. Scalar Arguments .. */ |
|
/* .. */ |
|
/* .. Array Arguments .. */ |
|
/* .. */ |
|
|
|
/* Purpose */ |
|
/* ======= */ |
|
|
|
/* DGEQRF computes a QR factorization of a real M-by-N matrix A: */ |
|
/* A = Q * R. */ |
|
|
|
/* 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 above the diagonal of the array */ |
|
/* contain the min(M,N)-by-N upper trapezoidal matrix R (R is */ |
|
/* upper triangular if m >= n); the elements below the diagonal, */ |
|
/* with the array TAU, represent the orthogonal matrix Q as a */ |
|
/* product of min(m,n) 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/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK)) */ |
|
/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */ |
|
|
|
/* LWORK (input) INTEGER */ |
|
/* The dimension of the array WORK. LWORK >= max(1,N). */ |
|
/* For optimum performance LWORK >= N*NB, where NB is */ |
|
/* the optimal blocksize. */ |
|
|
|
/* If LWORK = -1, then a workspace query is assumed; the routine */ |
|
/* only calculates the optimal size of the WORK array, returns */ |
|
/* this value as the first entry of the WORK array, and no error */ |
|
/* message related to LWORK is issued by XERBLA. */ |
|
|
|
/* 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(1) H(2) . . . H(k), 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:m) is stored on exit in A(i+1:m,i), */ |
|
/* and tau in TAU(i). */ |
|
|
|
/* ===================================================================== */ |
|
|
|
/* .. Local Scalars .. */ |
|
/* .. */ |
|
/* .. External Subroutines .. */ |
|
/* .. */ |
|
/* .. Intrinsic Functions .. */ |
|
/* .. */ |
|
/* .. External 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; |
|
nb = ilaenv_(&c__1, "DGEQRF", " ", m, n, &c_n1, &c_n1); |
|
lwkopt = *n * nb; |
|
work[1] = (doublereal) lwkopt; |
|
lquery = *lwork == -1; |
|
if (*m < 0) { |
|
*info = -1; |
|
} else if (*n < 0) { |
|
*info = -2; |
|
} else if (*lda < max(1,*m)) { |
|
*info = -4; |
|
} else if (*lwork < max(1,*n) && ! lquery) { |
|
*info = -7; |
|
} |
|
if (*info != 0) { |
|
i__1 = -(*info); |
|
xerbla_("DGEQRF", &i__1); |
|
return 0; |
|
} else if (lquery) { |
|
return 0; |
|
} |
|
|
|
/* Quick return if possible */ |
|
|
|
k = min(*m,*n); |
|
if (k == 0) { |
|
work[1] = 1.; |
|
return 0; |
|
} |
|
|
|
nbmin = 2; |
|
nx = 0; |
|
iws = *n; |
|
if (nb > 1 && nb < k) { |
|
|
|
/* Determine when to cross over from blocked to unblocked code. */ |
|
|
|
/* Computing MAX */ |
|
i__1 = 0, i__2 = ilaenv_(&c__3, "DGEQRF", " ", m, n, &c_n1, &c_n1); |
|
nx = max(i__1,i__2); |
|
if (nx < k) { |
|
|
|
/* Determine if workspace is large enough for blocked code. */ |
|
|
|
ldwork = *n; |
|
iws = ldwork * nb; |
|
if (*lwork < iws) { |
|
|
|
/* Not enough workspace to use optimal NB: reduce NB and */ |
|
/* determine the minimum value of NB. */ |
|
|
|
nb = *lwork / ldwork; |
|
/* Computing MAX */ |
|
i__1 = 2, i__2 = ilaenv_(&c__2, "DGEQRF", " ", m, n, &c_n1, & |
|
c_n1); |
|
nbmin = max(i__1,i__2); |
|
} |
|
} |
|
} |
|
|
|
if (nb >= nbmin && nb < k && nx < k) { |
|
|
|
/* Use blocked code initially */ |
|
|
|
i__1 = k - nx; |
|
i__2 = nb; |
|
for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) { |
|
/* Computing MIN */ |
|
i__3 = k - i__ + 1; |
|
ib = min(i__3,nb); |
|
|
|
/* Compute the QR factorization of the current block */ |
|
/* A(i:m,i:i+ib-1) */ |
|
|
|
i__3 = *m - i__ + 1; |
|
dgeqr2_(&i__3, &ib, &a[i__ + i__ * a_dim1], lda, &tau[i__], &work[ |
|
1], &iinfo); |
|
if (i__ + ib <= *n) { |
|
|
|
/* Form the triangular factor of the block reflector */ |
|
/* H = H(i) H(i+1) . . . H(i+ib-1) */ |
|
|
|
i__3 = *m - i__ + 1; |
|
dlarft_("Forward", "Columnwise", &i__3, &ib, &a[i__ + i__ * |
|
a_dim1], lda, &tau[i__], &work[1], &ldwork); |
|
|
|
/* Apply H' to A(i:m,i+ib:n) from the left */ |
|
|
|
i__3 = *m - i__ + 1; |
|
i__4 = *n - i__ - ib + 1; |
|
dlarfb_("Left", "Transpose", "Forward", "Columnwise", &i__3, & |
|
i__4, &ib, &a[i__ + i__ * a_dim1], lda, &work[1], & |
|
ldwork, &a[i__ + (i__ + ib) * a_dim1], lda, &work[ib |
|
+ 1], &ldwork); |
|
} |
|
/* L10: */ |
|
} |
|
} else { |
|
i__ = 1; |
|
} |
|
|
|
/* Use unblocked code to factor the last or only block. */ |
|
|
|
if (i__ <= k) { |
|
i__2 = *m - i__ + 1; |
|
i__1 = *n - i__ + 1; |
|
dgeqr2_(&i__2, &i__1, &a[i__ + i__ * a_dim1], lda, &tau[i__], &work[1] |
|
, &iinfo); |
|
} |
|
|
|
work[1] = (doublereal) iws; |
|
return 0; |
|
|
|
/* End of DGEQRF */ |
|
|
|
} /* dgeqrf_ */
|
|
|