cggsvp - compute unitary matrices
SUBROUTINE CGGSVP(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB, TOLA, TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK, TAU, WORK, INFO) CHARACTER*1 JOBU, JOBV, JOBQ COMPLEX A(LDA,*), B(LDB,*), U(LDU,*), V(LDV,*), Q(LDQ,*), TAU(*), WORK(*) INTEGER M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO INTEGER IWORK(*) REAL TOLA, TOLB REAL RWORK(*) SUBROUTINE CGGSVP_64(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB, TOLA, TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK, TAU, WORK, INFO) CHARACTER*1 JOBU, JOBV, JOBQ COMPLEX A(LDA,*), B(LDB,*), U(LDU,*), V(LDV,*), Q(LDQ,*), TAU(*), WORK(*) INTEGER*8 M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO INTEGER*8 IWORK(*) REAL TOLA, TOLB REAL RWORK(*) F95 INTERFACE SUBROUTINE GGSVP(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB, TOLA, TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK, TAU, WORK, INFO) CHARACTER(LEN=1) :: JOBU, JOBV, JOBQ COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A, B, U, V, Q INTEGER :: M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO INTEGER, DIMENSION(:) :: IWORK REAL :: TOLA, TOLB REAL, DIMENSION(:) :: RWORK SUBROUTINE GGSVP_64(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB, TOLA, TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK, TAU, WORK, INFO) CHARACTER(LEN=1) :: JOBU, JOBV, JOBQ COMPLEX, DIMENSION(:) :: TAU, WORK COMPLEX, DIMENSION(:,:) :: A, B, U, V, Q INTEGER(8) :: M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO INTEGER(8), DIMENSION(:) :: IWORK REAL :: TOLA, TOLB REAL, DIMENSION(:) :: RWORK C INTERFACE #include <sunperf.h> void cggsvp(char jobu, char jobv, char jobq, int m, int p, int n, com- plex *a, int lda, complex *b, int ldb, float tola, float tolb, int *k, int *l, complex *u, int ldu, complex *v, int ldv, complex *q, int ldq, int *info); void cggsvp_64(char jobu, char jobv, char jobq, long m, long p, long n, complex *a, long lda, complex *b, long ldb, float tola, float tolb, long *k, long *l, complex *u, long ldu, complex *v, long ldv, complex *q, long ldq, long *info);
Oracle Solaris Studio Performance Library cggsvp(3P)
NAME
cggsvp - compute unitary matrices
SYNOPSIS
SUBROUTINE CGGSVP(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB, TOLA,
TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK, TAU, WORK,
INFO)
CHARACTER*1 JOBU, JOBV, JOBQ
COMPLEX A(LDA,*), B(LDB,*), U(LDU,*), V(LDV,*), Q(LDQ,*), TAU(*),
WORK(*)
INTEGER M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO
INTEGER IWORK(*)
REAL TOLA, TOLB
REAL RWORK(*)
SUBROUTINE CGGSVP_64(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB, TOLA,
TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK, TAU, WORK,
INFO)
CHARACTER*1 JOBU, JOBV, JOBQ
COMPLEX A(LDA,*), B(LDB,*), U(LDU,*), V(LDV,*), Q(LDQ,*), TAU(*),
WORK(*)
INTEGER*8 M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO
INTEGER*8 IWORK(*)
REAL TOLA, TOLB
REAL RWORK(*)
F95 INTERFACE
SUBROUTINE GGSVP(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B, LDB,
TOLA, TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK, RWORK,
TAU, WORK, INFO)
CHARACTER(LEN=1) :: JOBU, JOBV, JOBQ
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A, B, U, V, Q
INTEGER :: M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO
INTEGER, DIMENSION(:) :: IWORK
REAL :: TOLA, TOLB
REAL, DIMENSION(:) :: RWORK
SUBROUTINE GGSVP_64(JOBU, JOBV, JOBQ, M, P, N, A, LDA, B,
LDB, TOLA, TOLB, K, L, U, LDU, V, LDV, Q, LDQ, IWORK,
RWORK, TAU, WORK, INFO)
CHARACTER(LEN=1) :: JOBU, JOBV, JOBQ
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A, B, U, V, Q
INTEGER(8) :: M, P, N, LDA, LDB, K, L, LDU, LDV, LDQ, INFO
INTEGER(8), DIMENSION(:) :: IWORK
REAL :: TOLA, TOLB
REAL, DIMENSION(:) :: RWORK
C INTERFACE
#include <sunperf.h>
void cggsvp(char jobu, char jobv, char jobq, int m, int p, int n, com-
plex *a, int lda, complex *b, int ldb, float tola, float
tolb, int *k, int *l, complex *u, int ldu, complex *v, int
ldv, complex *q, int ldq, int *info);
void cggsvp_64(char jobu, char jobv, char jobq, long m, long p, long n,
complex *a, long lda, complex *b, long ldb, float tola, float
tolb, long *k, long *l, complex *u, long ldu, complex *v,
long ldv, complex *q, long ldq, long *info);
PURPOSE
cggsvp computes unitary matrices U, V and Q such that
L ( 0 0 A23 )
M-K-L ( 0 0 0 )
N-K-L K L
= K ( 0 A12 A13 ) if M-K-L < 0;
M-K ( 0 0 A23 )
N-K-L K L
V'*B*Q = L ( 0 0 B13 )
P-L ( 0 0 0 )
where the K-by-K matrix A12 and L-by-L matrix B13 are nonsingular upper
triangular; A23 is L-by-L upper triangular if M-K-L >= 0, otherwise A23
is (M-K)-by-L upper trapezoidal. K+L = the effective numerical rank of
the (M+P)-by-N matrix (A',B')'. Z' denotes the conjugate transpose of
Z.
This decomposition is the preprocessing step for computing the General-
ized Singular Value Decomposition (GSVD), see subroutine CGGSVD.
ARGUMENTS
JOBU (input)
= 'U': Unitary matrix U is computed;
= 'N': U is not computed.
JOBV (input)
= 'V': Unitary matrix V is computed;
= 'N': V is not computed.
JOBQ (input)
= 'Q': Unitary matrix Q is computed;
= 'N': Q is not computed.
M (input) The number of rows of the matrix A. M >= 0.
P (input) The number of rows of the matrix B. P >= 0.
N (input) The number of columns of the matrices A and B. N >= 0.
A (input/output)
On entry, the M-by-N matrix A. On exit, A contains the tri-
angular (or trapezoidal) matrix described in the Purpose sec-
tion.
LDA (input)
The leading dimension of the array A.
LDA >= max(1,M).
B (input/output)
On entry, the P-by-N matrix B.
On exit, B contains the triangular matrix described in the
Purpose section.
LDB (input)
The leading dimension of the array B.
LDB >= max(1,P).
TOLA (input)
TOLA and TOLB are the thresholds to determine the effective
numerical rank of matrix B and a subblock of A. Generally,
they are set to
TOLA = MAX(M,N)*norm(A)*MACHEPS,
TOLB = MAX(P,N)*norm(B)*MACHEPS.
The size of TOLA and TOLB may affect the size of backward
errors of the decomposition.
TOLB (input)
See description of TOLA.
K (output)
On exit, K and L specify the dimension of the subblocks
described in Purpose section.
K + L = effective numerical rank of (A',B')'.
L (output)
See the description of K.
U (output)
If JOBU = 'U', U contains the unitary matrix U.
If JOBU = 'N', U is not referenced.
LDU (input)
The leading dimension of the array U.
LDU >= max(1,M) if JOBU = 'U'; LDU >= 1 otherwise.
V (output)
If JOBV = 'V', V contains the unitary matrix V.
If JOBV = 'N', V is not referenced.
LDV (input)
The leading dimension of the array V.
LDV >= max(1,P) if JOBV = 'V'; LDV >= 1 otherwise.
Q (output)
If JOBQ = 'Q', Q contains the unitary matrix Q.
If JOBQ = 'N', Q is not referenced.
LDQ (input)
The leading dimension of the array Q.
LDQ >= max(1,N) if JOBQ = 'Q'; LDQ >= 1 otherwise.
IWORK (workspace)
dimension(N)
RWORK (workspace)
dimension(2*N)
TAU (workspace)
dimension(N)
WORK (workspace)
dimension(MAX(3*N,M,P))
INFO (output)
= 0: successful exit;
< 0: if INFO = -i, the i-th argument had an illegal value.
FURTHER DETAILS
The subroutine uses LAPACK subroutine CGEQPF for the QR factorization
with column pivoting to detect the effective numerical rank of the a
matrix. It may be replaced by a better rank determination strategy.
7 Nov 2015 cggsvp(3P)