1ZHPGST(1)                LAPACK routine (version 3.1)                ZHPGST(1)
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NAME

6       ZHPGST - a complex Hermitian-definite generalized eigenproblem to stan‐
7       dard form, using packed storage
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SYNOPSIS

10       SUBROUTINE ZHPGST( ITYPE, UPLO, N, AP, BP, INFO )
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12           CHARACTER      UPLO
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14           INTEGER        INFO, ITYPE, N
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16           COMPLEX*16     AP( * ), BP( * )
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PURPOSE

19       ZHPGST reduces a complex Hermitian-definite generalized eigenproblem to
20       standard form, using packed storage.
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22       If ITYPE = 1, the problem is A*x = lambda*B*x,
23       and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)
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25       If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
26       B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H*A*L.
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28       B must have been previously factorized as U**H*U or L*L**H by ZPPTRF.
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ARGUMENTS

32       ITYPE   (input) INTEGER
33               = 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H);
34               = 2 or 3: compute U*A*U**H or L**H*A*L.
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36       UPLO    (input) CHARACTER*1
37               =  'U':   Upper  triangle  of  A is stored and B is factored as
38               U**H*U; = 'L':  Lower triangle of A is stored and B is factored
39               as L*L**H.
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41       N       (input) INTEGER
42               The order of the matrices A and B.  N >= 0.
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44       AP      (input/output) COMPLEX*16 array, dimension (N*(N+1)/2)
45               On  entry,  the upper or lower triangle of the Hermitian matrix
46               A, packed columnwise in a linear array.  The j-th column  of  A
47               is  stored  in  the  array AP as follows: if UPLO = 'U', AP(i +
48               (j-1)*j/2) =  A(i,j)  for  1<=i<=j;  if  UPLO  =  'L',  AP(i  +
49               (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
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51               On  exit,  if  INFO  = 0, the transformed matrix, stored in the
52               same format as A.
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54       BP      (input) COMPLEX*16 array, dimension (N*(N+1)/2)
55               The triangular factor from the  Cholesky  factorization  of  B,
56               stored in the same format as A, as returned by ZPPTRF.
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58       INFO    (output) INTEGER
59               = 0:  successful exit
60               < 0:  if INFO = -i, the i-th argument had an illegal value
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64 LAPACK routine (version 3.1)    November 2006                       ZHPGST(1)
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