cgeqrf
cgeqrf - compute a QR factorization of a complex M-by-N matrix A
SUBROUTINE CGEQRF( M, N, A, LDA, TAU, WORK, LDWORK, INFO)
COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER M, N, LDA, LDWORK, INFO
SUBROUTINE CGEQRF_64( M, N, A, LDA, TAU, WORK, LDWORK, INFO)
COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER*8 M, N, LDA, LDWORK, INFO
SUBROUTINE GEQRF( [M], [N], A, [LDA], TAU, [WORK], [LDWORK], [INFO])
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: M, N, LDA, LDWORK, INFO
SUBROUTINE GEQRF_64( [M], [N], A, [LDA], TAU, [WORK], [LDWORK],
* [INFO])
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: M, N, LDA, LDWORK, INFO
#include <sunperf.h>
void cgeqrf(int m, int n, complex *a, int lda, complex *tau, int *info);
void cgeqrf_64(long m, long n, complex *a, long lda, complex *tau, long *info);
cgeqrf computes a QR factorization of a complex M-by-N matrix A:
A = Q * R.
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* M (input)
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The number of rows of the matrix A. M >= 0.
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* N (input)
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The number of columns of the matrix A. N >= 0.
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* A (input/output)
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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 unitary matrix Q as a
product of min(m,n) elementary reflectors (see Further
Details).
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* LDA (input)
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The leading dimension of the array A. LDA >= max(1,M).
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* TAU (output)
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The scalar factors of the elementary reflectors (see Further
Details).
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* WORK (workspace)
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On exit, if INFO = 0, WORK(1) returns the optimal LDWORK.
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* LDWORK (input)
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The dimension of the array WORK. LDWORK >= max(1,N).
For optimum performance LDWORK >= N*NB, where NB is
the optimal blocksize.
If LDWORK = -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 LDWORK is issued by XERBLA.
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* INFO (output)
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