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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/csyl01.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/csyl01.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/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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Version 3.12.0 LAPACK