ZTRT01 computes the residual for a triangular matrix A times its


 inverse:


    RESID = norm( A*AINV - I ) / ( N * norm(A) * norm(AINV) * EPS ),


 where EPS is the machine epsilon.

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.

A

          A is COMPLEX*16 array, dimension (LDA,N)


          The triangular matrix A.  If UPLO = 'U', the leading n by n


          upper triangular part of the array A contains the upper


          triangular matrix, and the strictly lower triangular part of


          A is not referenced.  If UPLO = 'L', the leading n by n lower


          triangular part of the array A contains the lower triangular


          matrix, and the strictly upper triangular part of A is not


          referenced.  If DIAG = 'U', the diagonal elements of A are


          also not referenced and are assumed to be 1.

LDA

          LDA is INTEGER


          The leading dimension of the array A.  LDA >= max(1,N).

AINV

          AINV is COMPLEX*16 array, dimension (LDAINV,N)


          On entry, the (triangular) inverse of the matrix A, in the


          same storage format as A.


          On exit, the contents of AINV are destroyed.

LDAINV

          LDAINV is INTEGER


          The leading dimension of the array AINV.  LDAINV >= max(1,N).

RCOND

          RCOND is DOUBLE PRECISION


          The reciprocal condition number of A, computed as


          1/(norm(A) * norm(AINV)).

RWORK

          RWORK is DOUBLE PRECISION array, dimension (N)

RESID

          RESID is DOUBLE PRECISION


          norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS )

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.