stzrzf
stzrzf - reduce the M-by-N ( M<=N ) real upper trapezoidal matrix A to upper triangular form by means of orthogonal transformations
SUBROUTINE STZRZF( M, N, A, LDA, TAU, WORK, LWORK, INFO)
INTEGER M, N, LDA, LWORK, INFO
REAL A(LDA,*), TAU(*), WORK(*)
SUBROUTINE STZRZF_64( M, N, A, LDA, TAU, WORK, LWORK, INFO)
INTEGER*8 M, N, LDA, LWORK, INFO
REAL A(LDA,*), TAU(*), WORK(*)
SUBROUTINE TZRZF( [M], [N], A, [LDA], TAU, [WORK], [LWORK], [INFO])
INTEGER :: M, N, LDA, LWORK, INFO
REAL, DIMENSION(:) :: TAU, WORK
REAL, DIMENSION(:,:) :: A
SUBROUTINE TZRZF_64( [M], [N], A, [LDA], TAU, [WORK], [LWORK], [INFO])
INTEGER(8) :: M, N, LDA, LWORK, INFO
REAL, DIMENSION(:) :: TAU, WORK
REAL, DIMENSION(:,:) :: A
#include <sunperf.h>
void stzrzf(int m, int n, float *a, int lda, float *tau, int *info);
void stzrzf_64(long m, long n, float *a, long lda, float *tau, long *info);
stzrzf reduces the M-by-N ( M<=N ) real upper trapezoidal matrix A
to upper triangular form by means of orthogonal transformations.
The upper trapezoidal matrix A is factored as
A = ( R 0 ) * Z,
where Z is an N-by-N orthogonal matrix and R is an M-by-M upper
triangular matrix.
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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 leading M-by-N upper trapezoidal part of the
array A must contain the matrix to be factorized.
On exit, the leading M-by-M upper triangular part of A
contains the upper triangular matrix R, and elements M+1 to
N of the first M rows of A, with the array TAU, represent the
orthogonal matrix Z as a product of M elementary reflectors.
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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.
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* WORK (workspace)
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On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
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* LWORK (input)
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The dimension of the array WORK. LWORK >= max(1,M).
For optimum performance LWORK >= M*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.
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* INFO (output)
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