TESTING/LIN/stpt01.f(3)

NAME
TESTING/LIN/stpt01.f

SYNOPSIS

  Functions/Subroutines
subroutine stpt01 (uplo, diag, n, ap, ainvp, rcond, work, resid)
STPT01

Function/Subroutine Documentation

  subroutine stpt01 (character uplo, character diag, integer n, real, dimension( * ) ap, real, dimension( * ) ainvp, real rcond, real, dimension( * ) work, real resid)

STPT01

Purpose:

     STPT01 computes the residual for a triangular matrix A times its
     inverse when A is stored in packed format:
        RESID = norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ),
     where EPS is the machine epsilon.

Parameters
    UPLO

              UPLO is CHARACTER*1
              Specifies whether the matrix A is upper or lower triangular.
              = 'U':  Upper triangular
              = 'L':  Lower triangular

    DIAG

              DIAG is CHARACTER*1
              Specifies whether or not the matrix A is unit triangular.
              = 'N':  Non-unit triangular
              = 'U':  Unit triangular

    N

              N is INTEGER
              The order of the matrix A.  N >= 0.

    AP

              AP is REAL array, dimension (N*(N+1)/2)
              The original upper or lower triangular matrix A, packed
              columnwise in a linear array.  The j-th column of A is stored
              in the array AP as follows:
              if UPLO = 'U', AP((j-1)*j/2 + i) = A(i,j) for 1<=i<=j;
              if UPLO = 'L',
                 AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.

    AINVP

              AINVP is REAL array, dimension (N*(N+1)/2)
              On entry, the (triangular) inverse of the matrix A, packed
              columnwise in a linear array as in AP.
              On exit, the contents of AINVP are destroyed.

    RCOND

              RCOND is REAL
              The reciprocal condition number of A, computed as
              1/(norm(A) * norm(AINV)).

    WORK

              WORK is REAL array, dimension (N)

    RESID

              RESID is REAL
              norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS )

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 107 of file stpt01.f.

Author

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