cgerq2 - computes the RQ factorization of a general rectangular matrix using an unblocked algorithm
SUBROUTINE CGERQ2(M, N, A, LDA, TAU, WORK, INFO) INTEGER INFO, LDA, M, N COMPLEX A(LDA,*), TAU(*), WORK(*) SUBROUTINE CGERQ2_64(M, N, A, LDA, TAU, WORK, INFO) INTEGER*8 INFO, LDA, M, N COMPLEX A(LDA,*), TAU(*), WORK(*) F95 INTERFACE SUBROUTINE GERQ2(M, N, A, LDA, TAU, WORK, INFO) INTEGER :: M, N, LDA, INFO COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A SUBROUTINE GERQ2_64(M, N, A, LDA, TAU, WORK, INFO) INTEGER(8) :: M, N, LDA, INFO COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A C INTERFACE #include <sunperf.h> void cgerq2 (int m, int n, floatcomplex *a, int lda, floatcomplex *tau, int *info); void cgerq2_64 (long m, long n, floatcomplex *a, long lda, floatcomplex *tau, long *info);
Oracle Solaris Studio Performance Library cgerq2(3P) NAME cgerq2 - computes the RQ factorization of a general rectangular matrix using an unblocked algorithm SYNOPSIS SUBROUTINE CGERQ2(M, N, A, LDA, TAU, WORK, INFO) INTEGER INFO, LDA, M, N COMPLEX A(LDA,*), TAU(*), WORK(*) SUBROUTINE CGERQ2_64(M, N, A, LDA, TAU, WORK, INFO) INTEGER*8 INFO, LDA, M, N COMPLEX A(LDA,*), TAU(*), WORK(*) F95 INTERFACE SUBROUTINE GERQ2(M, N, A, LDA, TAU, WORK, INFO) INTEGER :: M, N, LDA, INFO COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A SUBROUTINE GERQ2_64(M, N, A, LDA, TAU, WORK, INFO) INTEGER(8) :: M, N, LDA, INFO COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A C INTERFACE #include <sunperf.h> void cgerq2 (int m, int n, floatcomplex *a, int lda, floatcomplex *tau, int *info); void cgerq2_64 (long m, long n, floatcomplex *a, long lda, floatcomplex *tau, long *info); PURPOSE cgerq2 computes an RQ factorization of a complex M by N matrix A: A = R * Q. ARGUMENTS M (input) M is INTEGER The number of rows of the matrix A. M >= 0. N (input) N is INTEGER The number of columns of the matrix A. N >= 0. A (input/output) A is COMPLEX array, dimension (LDA,N) 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 unitary matrix Q as a product of elementary reflectors (see Further Details). LDA (input) LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). TAU (output) TAU is COMPLEX array, dimension (min(M,N)) The scalar factors of the elementary reflectors (see Further Details). WORK (output) WORK is COMPLEX array, dimension (M) INFO (output) INFO is 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 H(2)**H . . . H(k)**H, where k = min(m,n). Each H(i) has the form H(i) = I - tau * v * v**H where tau is a complex scalar, and v is a complex vector with v(n-k+i+1:n) = 0 and v(n-k+i) = 1; conjg(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 cgerq2(3P)