1ZHER2(1)                         BLAS routine                         ZHER2(1)
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NAME

6       ZHER2  -  performs the hermitian rank 2 operation   A := alpha*x*conjg(
7       y' ) + conjg( alpha )*y*conjg( x' ) + A,
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SYNOPSIS

10       SUBROUTINE ZHER2(UPLO,N,ALPHA,X,INCX,Y,INCY,A,LDA)
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12           DOUBLE                                         COMPLEX ALPHA
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14           INTEGER                                        INCX,INCY,LDA,N
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16           CHARACTER                                      UPLO
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18           DOUBLE                                         COMPLEX
19                                                          A(LDA,*),X(*),Y(*)
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PURPOSE

22       ZHER2  performs the hermitian rank 2 operation
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24       where alpha is a scalar, x and y are n element vectors and A is an n by
25       n hermitian matrix.
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ARGUMENTS

29       UPLO   - CHARACTER*1.
30              On entry, UPLO specifies whether the upper or  lower  triangular
31              part of the array A is to be referenced as follows:
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33              UPLO = 'U' or 'u'   Only the upper triangular part of A is to be
34              referenced.
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36              UPLO = 'L' or 'l'   Only the lower triangular part of A is to be
37              referenced.
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39              Unchanged on exit.
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41       N      - INTEGER.
42              On  entry,  N specifies the order of the matrix A.  N must be at
43              least zero.  Unchanged on exit.
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45       ALPHA  - COMPLEX*16      .
46              On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.
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48       X      - COMPLEX*16       array of dimension at least
49              ( 1 + ( n - 1 )*abs( INCX ) ).  Before  entry,  the  incremented
50              array X must contain the n element vector x.  Unchanged on exit.
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52       INCX   - INTEGER.
53              On  entry,  INCX  specifies the increment for the elements of X.
54              INCX must not be zero.  Unchanged on exit.
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56       Y      - COMPLEX*16       array of dimension at least
57              ( 1 + ( n - 1 )*abs( INCY ) ).  Before  entry,  the  incremented
58              array Y must contain the n element vector y.  Unchanged on exit.
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60       INCY   - INTEGER.
61              On  entry,  INCY  specifies the increment for the elements of Y.
62              INCY must not be zero.  Unchanged on exit.
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64       A      - COMPLEX*16       array of DIMENSION ( LDA, n ).
65              Before entry with  UPLO = 'U' or 'u', the leading n by  n  upper
66              triangular part of the array A must contain the upper triangular
67              part of the hermitian matrix and the strictly  lower  triangular
68              part  of A is not referenced. On exit, the upper triangular part
69              of the array A is overwritten by the upper  triangular  part  of
70              the  updated  matrix.   Before entry with UPLO = 'L' or 'l', the
71              leading n by n lower triangular part of the array A must contain
72              the  lower  triangular  part  of  the  hermitian  matrix and the
73              strictly upper triangular part of A is not referenced. On  exit,
74              the  lower  triangular part of the array A is overwritten by the
75              lower triangular part of the  updated  matrix.   Note  that  the
76              imaginary  parts  of the diagonal elements need not be set, they
77              are assumed to be zero, and on exit they are set to zero.
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79       LDA    - INTEGER.
80              On entry, LDA specifies the first dimension of A as declared  in
81              the  calling  (sub)  program.  LDA must be at least max( 1, n ).
82              Unchanged on exit.
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FURTHER DETAILS

85       Level 2 Blas routine.
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87       -- Written on 22-October-1986.
88          Jack Dongarra, Argonne National Lab.
89          Jeremy Du Croz, Nag Central Office.
90          Sven Hammarling, Nag Central Office.
91          Richard Hanson, Sandia National Labs.
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96BLAS routine                     November 2008                        ZHER2(1)
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