.TH "SRC/DEPRECATED/sggsvp.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/DEPRECATED/sggsvp.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBsggsvp\fP (jobu, jobv, jobq, m, p, n, a, lda, b, ldb, tola, tolb, k, l, u, ldu, v, ldv, q, ldq, iwork, tau, work, info)" .br .RI "\fBSGGSVP\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine sggsvp (character jobu, character jobv, character jobq, integer m, integer p, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( ldb, * ) b, integer ldb, real tola, real tolb, integer k, integer l, real, dimension( ldu, * ) u, integer ldu, real, dimension( ldv, * ) v, integer ldv, real, dimension( ldq, * ) q, integer ldq, integer, dimension( * ) iwork, real, dimension( * ) tau, real, dimension( * ) work, integer info)" .PP \fBSGGSVP\fP .PP \fBPurpose:\fP .RS 4 .PP .nf This routine is deprecated and has been replaced by routine SGGSVP3\&. SGGSVP computes orthogonal matrices U, V and Q such that N-K-L K L U**T*A*Q = K ( 0 A12 A13 ) if M-K-L >= 0; 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**T*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**T,B**T)**T\&. This decomposition is the preprocessing step for computing the Generalized Singular Value Decomposition (GSVD), see subroutine SGGSVD\&. .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIJOBU\fP .PP .nf JOBU is CHARACTER*1 = 'U': Orthogonal matrix U is computed; = 'N': U is not computed\&. .fi .PP .br \fIJOBV\fP .PP .nf JOBV is CHARACTER*1 = 'V': Orthogonal matrix V is computed; = 'N': V is not computed\&. .fi .PP .br \fIJOBQ\fP .PP .nf JOBQ is CHARACTER*1 = 'Q': Orthogonal matrix Q is computed; = 'N': Q is not computed\&. .fi .PP .br \fIM\fP .PP .nf M is INTEGER The number of rows of the matrix A\&. M >= 0\&. .fi .PP .br \fIP\fP .PP .nf P is INTEGER The number of rows of the matrix B\&. P >= 0\&. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The number of columns of the matrices A and B\&. N >= 0\&. .fi .PP .br \fIA\fP .PP .nf A is REAL array, dimension (LDA,N) On entry, the M-by-N matrix A\&. On exit, A contains the triangular (or trapezoidal) matrix described in the Purpose section\&. .fi .PP .br \fILDA\fP .PP .nf LDA is INTEGER The leading dimension of the array A\&. LDA >= max(1,M)\&. .fi .PP .br \fIB\fP .PP .nf B is REAL array, dimension (LDB,N) On entry, the P-by-N matrix B\&. On exit, B contains the triangular matrix described in the Purpose section\&. .fi .PP .br \fILDB\fP .PP .nf LDB is INTEGER The leading dimension of the array B\&. LDB >= max(1,P)\&. .fi .PP .br \fITOLA\fP .PP .nf TOLA is REAL .fi .PP .br \fITOLB\fP .PP .nf TOLB is REAL 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\&. .fi .PP .br \fIK\fP .PP .nf K is INTEGER .fi .PP .br \fIL\fP .PP .nf L is INTEGER On exit, K and L specify the dimension of the subblocks described in Purpose section\&. K + L = effective numerical rank of (A**T,B**T)**T\&. .fi .PP .br \fIU\fP .PP .nf U is REAL array, dimension (LDU,M) If JOBU = 'U', U contains the orthogonal matrix U\&. If JOBU = 'N', U is not referenced\&. .fi .PP .br \fILDU\fP .PP .nf LDU is INTEGER The leading dimension of the array U\&. LDU >= max(1,M) if JOBU = 'U'; LDU >= 1 otherwise\&. .fi .PP .br \fIV\fP .PP .nf V is REAL array, dimension (LDV,P) If JOBV = 'V', V contains the orthogonal matrix V\&. If JOBV = 'N', V is not referenced\&. .fi .PP .br \fILDV\fP .PP .nf LDV is INTEGER The leading dimension of the array V\&. LDV >= max(1,P) if JOBV = 'V'; LDV >= 1 otherwise\&. .fi .PP .br \fIQ\fP .PP .nf Q is REAL array, dimension (LDQ,N) If JOBQ = 'Q', Q contains the orthogonal matrix Q\&. If JOBQ = 'N', Q is not referenced\&. .fi .PP .br \fILDQ\fP .PP .nf LDQ is INTEGER The leading dimension of the array Q\&. LDQ >= max(1,N) if JOBQ = 'Q'; LDQ >= 1 otherwise\&. .fi .PP .br \fIIWORK\fP .PP .nf IWORK is INTEGER array, dimension (N) .fi .PP .br \fITAU\fP .PP .nf TAU is REAL array, dimension (N) .fi .PP .br \fIWORK\fP .PP .nf WORK is REAL array, dimension (max(3*N,M,P)) .fi .PP .br \fIINFO\fP .PP .nf INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value\&. .fi .PP .RE .PP \fBAuthor\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP \fBFurther Details:\fP .RS 4 The subroutine uses LAPACK subroutine SGEQPF 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\&. .RE .PP .PP Definition at line \fB253\fP of file \fBsggsvp\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.