sormtr(3P) Sun Performance Library sormtr(3P)NAMEsormtr - overwrite the general real M-by-N matrix C with Q*C or Q**T*C
or C*Q**T or C*Q.
SYNOPSIS
SUBROUTINE SORMTR(SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC, WORK,
LWORK, INFO)
CHARACTER * 1 SIDE, UPLO, TRANS
INTEGER M, N, LDA, LDC, LWORK, INFO
REAL A(LDA,*), TAU(*), C(LDC,*), WORK(*)
SUBROUTINE SORMTR_64(SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC,
WORK, LWORK, INFO)
CHARACTER * 1 SIDE, UPLO, TRANS
INTEGER*8 M, N, LDA, LDC, LWORK, INFO
REAL A(LDA,*), TAU(*), C(LDC,*), WORK(*)
F95 INTERFACE
SUBROUTINE ORMTR(SIDE, UPLO, [TRANS], [M], [N], A, [LDA], TAU, C,
[LDC], [WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, UPLO, TRANS
INTEGER :: M, N, LDA, LDC, LWORK, INFO
REAL, DIMENSION(:) :: TAU, WORK
REAL, DIMENSION(:,:) :: A, C
SUBROUTINE ORMTR_64(SIDE, UPLO, [TRANS], [M], [N], A, [LDA], TAU, C,
[LDC], [WORK], [LWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, UPLO, TRANS
INTEGER(8) :: M, N, LDA, LDC, LWORK, INFO
REAL, DIMENSION(:) :: TAU, WORK
REAL, DIMENSION(:,:) :: A, C
C INTERFACE
#include <sunperf.h>
void sormtr(char side, char uplo, char trans, int m, int n, float *a,
int lda, float *tau, float *c, int ldc, int *info);
void sormtr_64(char side, char uplo, char trans, long m, long n, float
*a, long lda, float *tau, float *c, long ldc, long *info);
PURPOSEsormtr overwrites the general real M-by-N matrix C with
SIDE = 'L' SIDE = 'R'
TRANS = 'N': Q * C C * Q
TRANS = 'T': Q**T * C C * Q**T
where Q is a real orthogonal matrix of order nq, with nq = m if SIDE =
'L' and nq = n if SIDE = 'R'. Q is defined as the product of nq-1 ele‐
mentary reflectors, as returned by SSYTRD:
if UPLO = 'U', Q = H(nq-1) . . . H(2)H(1);
if UPLO = 'L', Q = H(1)H(2) . . . H(nq-1).
ARGUMENTS
SIDE (input)
= 'L': apply Q or Q**T from the Left;
= 'R': apply Q or Q**T from the Right.
UPLO (input)
= 'U': Upper triangle of A contains elementary reflectors
from SSYTRD;
= 'L': Lower triangle of A contains elementary reflectors
from SSYTRD.
TRANS (input)
= 'N': No transpose, apply Q;
= 'T': Transpose, apply Q**T.
TRANS is defaulted to 'N' for F95 INTERFACE.
M (input)
The number of rows of the matrix C. M >= 0.
N (input)
The number of columns of the matrix C. N >= 0.
A (input)
dimension
(LDA,M) if SIDE = 'L'
(LDA,N) if SIDE = 'R'
The vectors which define the elementary reflectors, as
returned by SSYTRD.
LDA (input)
The leading dimension of the array A.
LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'.
TAU (input)
dimension
(M-1) if SIDE = 'L'
(N-1) if SIDE = 'R'
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by SSYTRD.
C (input/output)
dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.
LDC (input)
The leading dimension of the array C. LDC >= max(1,M).
WORK (workspace)
dimension (LWORK)
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK (input)
The dimension of the array WORK.
If SIDE = 'L', LWORK >= max(1,N);
if SIDE = 'R', LWORK >= max(1,M).
For optimum performance LWORK >= N*NB if SIDE = 'L', and
LWORK >= M*NB if SIDE = 'R', where NB is the optimal block‐
size.
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.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
6 Mar 2009 sormtr(3P)
