.TH "SRC/sorghr.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/sorghr.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBsorghr\fP (n, ilo, ihi, a, lda, tau, work, lwork, info)" .br .RI "\fBSORGHR\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine sorghr (integer n, integer ilo, integer ihi, real, dimension( lda, * ) a, integer lda, real, dimension( * ) tau, real, dimension( * ) work, integer lwork, integer info)" .PP \fBSORGHR\fP .PP \fBPurpose:\fP .RS 4 .PP .nf !> !> SORGHR generates a real orthogonal matrix Q which is defined as the !> product of IHI-ILO elementary reflectors of order N, as returned by !> SGEHRD: !> !> Q = H(ilo) H(ilo+1) \&. \&. \&. H(ihi-1)\&. !> .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIN\fP .PP .nf !> N is INTEGER !> The order of the matrix Q\&. N >= 0\&. !> .fi .PP .br \fIILO\fP .PP .nf !> ILO is INTEGER !> .fi .PP .br \fIIHI\fP .PP .nf !> IHI is INTEGER !> !> ILO and IHI must have the same values as in the previous call !> of SGEHRD\&. Q is equal to the unit matrix except in the !> submatrix Q(ilo+1:ihi,ilo+1:ihi)\&. !> 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0\&. !> .fi .PP .br \fIA\fP .PP .nf !> A is REAL array, dimension (LDA,N) !> On entry, the vectors which define the elementary reflectors, !> as returned by SGEHRD\&. !> On exit, the N-by-N orthogonal matrix Q\&. !> .fi .PP .br \fILDA\fP .PP .nf !> LDA is INTEGER !> The leading dimension of the array A\&. LDA >= max(1,N)\&. !> .fi .PP .br \fITAU\fP .PP .nf !> TAU is REAL array, dimension (N-1) !> TAU(i) must contain the scalar factor of the elementary !> reflector H(i), as returned by SGEHRD\&. !> .fi .PP .br \fIWORK\fP .PP .nf !> WORK is REAL array, dimension (MAX(1,LWORK)) !> On exit, if INFO = 0, WORK(1) returns the optimal LWORK\&. !> .fi .PP .br \fILWORK\fP .PP .nf !> LWORK is INTEGER !> The dimension of the array WORK\&. LWORK >= IHI-ILO\&. !> For optimum performance LWORK >= (IHI-ILO)*NB, 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\&. !> .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 .PP Definition at line \fB125\fP of file \fBsorghr\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.