TESTING/EIG/csyl01.f(3)    Library Functions Manual    TESTING/EIG/csyl01.f(3)

NAME
       TESTING/EIG/csyl01.f

SYNOPSIS
   Functions/Subroutines
       subroutine csyl01 (thresh, nfail, rmax, ninfo, knt)
           CSYL01

Function/Subroutine Documentation
   subroutine csyl01 (real thresh, integer, dimension( 3 ) nfail, real,
       dimension( 2 ) rmax, integer, dimension( 2 ) ninfo, integer knt)
       CSYL01

       Purpose:


           !>
           !> CSYL01 tests CTRSYL and CTRSYL3, 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 CGET35 by testing with larger,
           !> random matrices, of which some require rescaling of X to avoid overflow.
           !>
           !>

       Parameters
           THRESH

           !>          THRESH is REAL
           !>          A test will count as  if the residual, computed as
           !>          described above, exceeds THRESH.
           !>

           NFAIL

           !>          NFAIL is INTEGER array, dimension (3)
           !>          NFAIL(1) = No. of times residual CTRSYL exceeds threshold THRESH
           !>          NFAIL(2) = No. of times residual CTRSYL3 exceeds threshold THRESH
           !>          NFAIL(3) = No. of times CTRSYL3 and CTRSYL deviate
           !>

           RMAX

           !>          RMAX is DOUBLE PRECISION array, dimension (2)
           !>          RMAX(1) = Value of the largest test ratio of CTRSYL
           !>          RMAX(2) = Value of the largest test ratio of CTRSYL3
           !>

           NINFO

           !>          NINFO is INTEGER array, dimension (2)
           !>          NINFO(1) = No. of times CTRSYL where INFO is nonzero
           !>          NINFO(2) = No. of times CTRSYL3 where INFO is nonzero
           !>

           KNT

           !>          KNT is INTEGER
           !>          Total number of examples tested.
           !>

       Definition at line 88 of file csyl01.f.

Author
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LAPACK                          Version 3.12.0         TESTING/EIG/csyl01.f(3)