TESTING/EIG/zsyl01.f(3) Library Functions Manual TESTING/EIG/zsyl01.f(3)

TESTING/EIG/zsyl01.f


subroutine zsyl01 (thresh, nfail, rmax, ninfo, knt)
ZSYL01

ZSYL01

Purpose:

 ZSYL01 tests ZTRSYL and ZTRSYL3, routines for solving the Sylvester matrix
 equation
    op(A)*X + ISGN*X*op(B) = scale*C,
 where op(A) and op(B) are both upper triangular form, op() represents an
 optional conjugate transpose, and ISGN can be -1 or +1. Scale is an output
 less than or equal to 1, chosen to avoid overflow in X.
 The test code verifies that the following residual does not exceed
 the provided threshold:
    norm(op(A)*X + ISGN*X*op(B) - scale*C) /
        (EPS*max(norm(A),norm(B))*norm(X))
 This routine complements ZGET35 by testing with larger,
 random matrices, of which some require rescaling of X to avoid overflow.

Parameters

THRESH
          THRESH is DOUBLE PRECISION
          A test will count as 'failed' if the residual, computed as
          described above, exceeds THRESH.

NFAIL

          NFAIL is INTEGER array, dimension (3)
          NFAIL(1) = No. of times residual ZTRSYL exceeds threshold THRESH
          NFAIL(2) = No. of times residual ZTRSYL3 exceeds threshold THRESH
          NFAIL(3) = No. of times ZTRSYL3 and ZTRSYL deviate

RMAX

          RMAX is DOUBLE PRECISION array, dimension (2)
          RMAX(1) = Value of the largest test ratio of ZTRSYL
          RMAX(2) = Value of the largest test ratio of ZTRSYL3

NINFO

          NINFO is INTEGER array, dimension (2)
          NINFO(1) = No. of times ZTRSYL returns an expected INFO
          NINFO(2) = No. of times ZTRSYL3 returns an expected INFO

KNT

          KNT is INTEGER
          Total number of examples tested.

Definition at line 88 of file zsyl01.f.

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK