Extends a complex Hermitian matrix defined in its upper triangle to its lower triangle.

Required Arguments

A — Complex Hermitian matrix of order N.   (Input/Output)
On input, the upper triangle of A defines a Hermitian matrix. On output, the lower triangle of A is defined so that A is Hermitian.

Optional Arguments

N — Order of the matrix.   (Input)
Default: N = size (A,2).

LDA — Leading dimension of A exactly as specified in the dimension statement of the calling program.   (Input)
Default: LDA = size (A,1).

FORTRAN 90 Interface

Generic:          CALL CHFCG (A [,…])

Specific:          The specific interface names are S_CHFCG and D_CHFCG.

FORTRAN 77 Interface

Single:             CALL CHFCG (N, A, LDA)

Double:                              The double precision name is DCHFCG.

Description

The routine CHFCG converts an N ´ N complex matrix A in Hermitian mode into a complex general matrix by filling in the lower triangular portion of A using the values defined in its upper triangular portion.

Comments

Informational errors

Type   Code

3           1                  The matrix is not Hermitian. It has a diagonal entry with a small imaginary part.

4           2                  The matrix is not Hermitian. It has a diagonal entry with an imaginary part.

Example

A complex 3 ´ 3 Hermitian matrix defined in its upper triangle is extended to its lower triangle.

 

      USE CHFCG_INT

      USE WRCRN_INT

 

      IMPLICIT   NONE

!                                 Declare variables

      INTEGER    LDA, N

      PARAMETER  (LDA=3, N=3)

!

      COMPLEX    A(LDA,N)

!                                 Set values for  A

!                           A = (  1.0+0.0i  1.0+1.0i  1.0+2.0i  )

!                               (            2.0+0.0i  2.0+2.0i  )

!                               (                      3.0+0.0i  )

!

      DATA A/(1.0,0.0), 2*(0.0,0.0), (1.0,1.0), (2.0,0.0), (0.0,0.0), &

          (1.0,2.0), (2.0,2.0), (3.0,0.0)/

!                                 Fill in lower Hermitian matrix

      CALL CHFCG (A)

!                                 Print results

      CALL WRCRN ('A', A)

      END

Output

 

                            A
                 1                2                3
1  ( 1.000, 0.000)  ( 1.000, 1.000)  ( 1.000, 2.000)
2  ( 1.000,-1.000)  ( 2.000, 0.000)  ( 2.000, 2.000)
3  ( 1.000,-2.000)  ( 2.000,-2.000)  ( 3.000, 0.000)

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