Contents
sormtr - overwrite the general real M-by-N matrix C with
SIDE = 'L' SIDE = 'R' TRANS = 'N'
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);
sormtr overwrites the general real M-by-N matrix C with
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 elementary 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).
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) (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)
(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)
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)
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 blocksize.
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 ille-
gal value