.TH "SRC/chegs2.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*-
.ad l
.nh
.SH NAME
SRC/chegs2.f
.SH SYNOPSIS
.br
.PP
.SS "Functions/Subroutines"

.in +1c
.ti -1c
.RI "subroutine \fBchegs2\fP (itype, uplo, n, a, lda, b, ldb, info)"
.br
.RI "\fBCHEGS2\fP reduces a Hermitian definite generalized eigenproblem to standard form, using the factorization results obtained from cpotrf (unblocked algorithm)\&. "
.in -1c
.SH "Function/Subroutine Documentation"
.PP 
.SS "subroutine chegs2 (integer itype, character uplo, integer n, complex, dimension( lda, * ) a, integer lda, complex, dimension( ldb, * ) b, integer ldb, integer info)"

.PP
\fBCHEGS2\fP reduces a Hermitian definite generalized eigenproblem to standard form, using the factorization results obtained from cpotrf (unblocked algorithm)\&.  
.PP
\fBPurpose:\fP
.RS 4

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.nf
!>
!> CHEGS2 reduces a complex Hermitian-definite generalized
!> eigenproblem to standard form\&.
!>
!> If ITYPE = 1, the problem is A*x = lambda*B*x,
!> and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)
!>
!> If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
!> B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H *A*L\&.
!>
!> B must have been previously factorized as U**H *U or L*L**H by ZPOTRF\&.
!> 
.fi
.PP
 
.RE
.PP
\fBParameters\fP
.RS 4
\fIITYPE\fP 
.PP
.nf
!>          ITYPE is INTEGER
!>          = 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H);
!>          = 2 or 3: compute U*A*U**H or L**H *A*L\&.
!> 
.fi
.PP
.br
\fIUPLO\fP 
.PP
.nf
!>          UPLO is CHARACTER*1
!>          Specifies whether the upper or lower triangular part of the
!>          Hermitian matrix A is stored, and how B has been factorized\&.
!>          = 'U':  Upper triangular
!>          = 'L':  Lower triangular
!> 
.fi
.PP
.br
\fIN\fP 
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.nf
!>          N is INTEGER
!>          The order of the matrices A and B\&.  N >= 0\&.
!> 
.fi
.PP
.br
\fIA\fP 
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.nf
!>          A is COMPLEX array, dimension (LDA,N)
!>          On entry, the Hermitian matrix A\&.  If UPLO = 'U', the leading
!>          n by n upper triangular part of A contains the upper
!>          triangular part of the matrix A, and the strictly lower
!>          triangular part of A is not referenced\&.  If UPLO = 'L', the
!>          leading n by n lower triangular part of A contains the lower
!>          triangular part of the matrix A, and the strictly upper
!>          triangular part of A is not referenced\&.
!>
!>          On exit, if INFO = 0, the transformed matrix, stored in the
!>          same format as A\&.
!> 
.fi
.PP
.br
\fILDA\fP 
.PP
.nf
!>          LDA is INTEGER
!>          The leading dimension of the array A\&.  LDA >= max(1,N)\&.
!> 
.fi
.PP
.br
\fIB\fP 
.PP
.nf
!>          B is COMPLEX array, dimension (LDB,N)
!>          The triangular factor from the Cholesky factorization of B,
!>          as returned by CPOTRF\&.
!>          B is modified by the routine but restored on exit\&.
!> 
.fi
.PP
.br
\fILDB\fP 
.PP
.nf
!>          LDB is INTEGER
!>          The leading dimension of the array B\&.  LDB >= 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 

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Univ\&. of Colorado Denver 

.PP
NAG Ltd\&. 
.RE
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Definition at line \fB127\fP of file \fBchegs2\&.f\fP\&.
.SH "Author"
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Generated automatically by Doxygen for LAPACK from the source code\&.