dbdt02.f - Man Page

subroutine dbdt02 (m, n, b, ldb, c, ldc, u, ldu, work, resid)
DBDT02

DBDT02

Purpose:

 DBDT02 tests the change of basis C = U**H * B by computing the
 residual

    RESID = norm(B - U * C) / ( max(m,n) * norm(B) * EPS ),

 where B and C are M by N matrices, U is an M by M orthogonal matrix,
 and EPS is the machine precision.

Parameters

M

          M is INTEGER
          The number of rows of the matrices B and C and the order of
          the matrix Q.

N

          N is INTEGER
          The number of columns of the matrices B and C.

B

          B is DOUBLE PRECISION array, dimension (LDB,N)
          The m by n matrix B.

LDB

          LDB is INTEGER
          The leading dimension of the array B.  LDB >= max(1,M).

C

          C is DOUBLE PRECISION array, dimension (LDC,N)
          The m by n matrix C, assumed to contain U**H * B.

LDC

          LDC is INTEGER
          The leading dimension of the array C.  LDC >= max(1,M).

U

          U is DOUBLE PRECISION array, dimension (LDU,M)
          The m by m orthogonal matrix U.

LDU

          LDU is INTEGER
          The leading dimension of the array U.  LDU >= max(1,M).

WORK

          WORK is DOUBLE PRECISION array, dimension (M)

RESID

          RESID is DOUBLE PRECISION
          RESID = norm(B - U * C) / ( max(m,n) * norm(B) * EPS ),

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 111 of file dbdt02.f.