.TH "cggbak.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME cggbak.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBcggbak\fP (JOB, SIDE, N, ILO, IHI, LSCALE, RSCALE, M, V, LDV, INFO)" .br .RI "\fI\fBCGGBAK\fP \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine cggbak (characterJOB, characterSIDE, integerN, integerILO, integerIHI, real, dimension( * )LSCALE, real, dimension( * )RSCALE, integerM, complex, dimension( ldv, * )V, integerLDV, integerINFO)" .PP \fBCGGBAK\fP .PP \fBPurpose: \fP .RS 4 .PP .nf CGGBAK forms the right or left eigenvectors of a complex generalized eigenvalue problem A*x = lambda*B*x, by backward transformation on the computed eigenvectors of the balanced pair of matrices output by CGGBAL. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIJOB\fP .PP .nf JOB is CHARACTER*1 Specifies the type of backward transformation required: = 'N': do nothing, return immediately; = 'P': do backward transformation for permutation only; = 'S': do backward transformation for scaling only; = 'B': do backward transformations for both permutation and scaling. JOB must be the same as the argument JOB supplied to CGGBAL. .fi .PP .br \fISIDE\fP .PP .nf SIDE is CHARACTER*1 = 'R': V contains right eigenvectors; = 'L': V contains left eigenvectors. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The number of rows of the matrix V. N >= 0. .fi .PP .br \fIILO\fP .PP .nf ILO is INTEGER .fi .PP .br \fIIHI\fP .PP .nf IHI is INTEGER The integers ILO and IHI determined by CGGBAL. 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0. .fi .PP .br \fILSCALE\fP .PP .nf LSCALE is REAL array, dimension (N) Details of the permutations and/or scaling factors applied to the left side of A and B, as returned by CGGBAL. .fi .PP .br \fIRSCALE\fP .PP .nf RSCALE is REAL array, dimension (N) Details of the permutations and/or scaling factors applied to the right side of A and B, as returned by CGGBAL. .fi .PP .br \fIM\fP .PP .nf M is INTEGER The number of columns of the matrix V. M >= 0. .fi .PP .br \fIV\fP .PP .nf V is COMPLEX array, dimension (LDV,M) On entry, the matrix of right or left eigenvectors to be transformed, as returned by CTGEVC. On exit, V is overwritten by the transformed eigenvectors. .fi .PP .br \fILDV\fP .PP .nf LDV is INTEGER The leading dimension of the matrix V. LDV >= max(1,N). .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 \fBDate:\fP .RS 4 November 2011 .RE .PP \fBFurther Details: \fP .RS 4 .PP .nf See R.C. Ward, Balancing the generalized eigenvalue problem, SIAM J. Sci. Stat. Comp. 2 (1981), 141-152. .fi .PP .RE .PP .PP Definition at line 148 of file cggbak\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.