dgerqf - N matrix A
SUBROUTINE DGERQF(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER M, N, LDA, LDWORK, INFO DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*) SUBROUTINE DGERQF_64(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER*8 M, N, LDA, LDWORK, INFO DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*) F95 INTERFACE SUBROUTINE GERQF(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER :: M, N, LDA, LDWORK, INFO REAL(8), DIMENSION(:) :: TAU, WORK REAL(8), DIMENSION(:,:) :: A SUBROUTINE GERQF_64(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER(8) :: M, N, LDA, LDWORK, INFO REAL(8), DIMENSION(:) :: TAU, WORK REAL(8), DIMENSION(:,:) :: A C INTERFACE #include <sunperf.h> void dgerqf(int m, int n, double *a, int lda, double *tau, int *info); void dgerqf_64(long m, long n, double *a, long lda, double *tau, long *info);
Oracle Solaris Studio Performance Library dgerqf(3P) NAME dgerqf - compute an RQ factorization of a real M-by-N matrix A SYNOPSIS SUBROUTINE DGERQF(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER M, N, LDA, LDWORK, INFO DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*) SUBROUTINE DGERQF_64(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER*8 M, N, LDA, LDWORK, INFO DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*) F95 INTERFACE SUBROUTINE GERQF(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER :: M, N, LDA, LDWORK, INFO REAL(8), DIMENSION(:) :: TAU, WORK REAL(8), DIMENSION(:,:) :: A SUBROUTINE GERQF_64(M, N, A, LDA, TAU, WORK, LDWORK, INFO) INTEGER(8) :: M, N, LDA, LDWORK, INFO REAL(8), DIMENSION(:) :: TAU, WORK REAL(8), DIMENSION(:,:) :: A C INTERFACE #include <sunperf.h> void dgerqf(int m, int n, double *a, int lda, double *tau, int *info); void dgerqf_64(long m, long n, double *a, long lda, double *tau, long *info); PURPOSE dgerqf computes an RQ factorization of a real M-by-N matrix A: A = R * Q. ARGUMENTS M (input) The number of rows of the matrix A. M >= 0. N (input) The number of columns of the matrix A. N >= 0. A (input/output) On entry, the M-by-N matrix A. On exit, if m <= n, the upper triangle of the subarray A(1:m,n-m+1:n) contains the M-by-M upper triangular matrix R; if m >= n, the elements on and above the (m-n)-th subdiagonal contain the M-by-N upper trapezoidal matrix R; the remaining elements, with the array TAU, represent the orthogonal matrix Q as a product of min(m,n) elementary reflectors (see Further Details). LDA (input) The leading dimension of the array A. LDA >= max(1,M). TAU (output) The scalar factors of the elementary reflectors (see Further Details). WORK (workspace) On exit, if INFO = 0, WORK(1) returns the optimal LDWORK. LDWORK (input) The dimension of the array WORK. LDWORK >= max(1,M). For optimum performance LDWORK >= M*NB, where NB is the optimal blocksize. If LDWORK = -1, then a workspace query is assumed; the rou- tine 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. INFO (output) = 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(n-k+i+1:n) = 0 and v(n-k+i) = 1; v(1:n-k+i-1) is stored on exit in A(m-k+i,1:n-k+i-1), and tau in TAU(i). 7 Nov 2015 dgerqf(3P)