LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

Go to the source code of this file.
Functions/Subroutines  
subroutine  sormtr (SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC, WORK, LWORK, INFO) 
SORMTR 
subroutine sormtr  (  character  SIDE, 
character  UPLO,  
character  TRANS,  
integer  M,  
integer  N,  
real, dimension( lda, * )  A,  
integer  LDA,  
real, dimension( * )  TAU,  
real, dimension( ldc, * )  C,  
integer  LDC,  
real, dimension( * )  WORK,  
integer  LWORK,  
integer  INFO  
) 
SORMTR
Download SORMTR + dependencies [TGZ] [ZIP] [TXT]SORMTR overwrites the general real MbyN 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 nq1 elementary reflectors, as returned by SSYTRD: if UPLO = 'U', Q = H(nq1) . . . H(2) H(1); if UPLO = 'L', Q = H(1) H(2) . . . H(nq1).
[in]  SIDE  SIDE is CHARACTER*1 = 'L': apply Q or Q**T from the Left; = 'R': apply Q or Q**T from the Right. 
[in]  UPLO  UPLO is CHARACTER*1 = 'U': Upper triangle of A contains elementary reflectors from SSYTRD; = 'L': Lower triangle of A contains elementary reflectors from SSYTRD. 
[in]  TRANS  TRANS is CHARACTER*1 = 'N': No transpose, apply Q; = 'T': Transpose, apply Q**T. 
[in]  M  M is INTEGER The number of rows of the matrix C. M >= 0. 
[in]  N  N is INTEGER The number of columns of the matrix C. N >= 0. 
[in]  A  A is REAL array, dimension (LDA,M) if SIDE = 'L' (LDA,N) if SIDE = 'R' The vectors which define the elementary reflectors, as returned by SSYTRD. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'. 
[in]  TAU  TAU is REAL array, dimension (M1) if SIDE = 'L' (N1) if SIDE = 'R' TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SSYTRD. 
[in,out]  C  C is REAL array, dimension (LDC,N) On entry, the MbyN matrix C. On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q. 
[in]  LDC  LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M). 
[out]  WORK  WORK is REAL array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. 
[in]  LWORK  LWORK is INTEGER 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. 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value 
Definition at line 172 of file sormtr.f.