TESTING/EIG/ssyl01.f(3) | Library Functions Manual | TESTING/EIG/ssyl01.f(3) |
NAME
TESTING/EIG/ssyl01.f
SYNOPSIS
Functions/Subroutines
subroutine ssyl01 (thresh, nfail, rmax, ninfo, knt)
SSYL01
Function/Subroutine Documentation
subroutine ssyl01 (real thresh, integer, dimension( 3 ) nfail, real, dimension( 2 ) rmax, integer, dimension( 2 ) ninfo, integer knt)
SSYL01
Purpose:
SSYL01 tests STRSYL and STRSYL3, routines for solving the Sylvester matrix equation op(A)*X + ISGN*X*op(B) = scale*C, A and B are assumed to be in Schur canonical form, op() represents an optional 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 SGET35 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 'failed' if the residual, computed as described above, exceeds THRESH.
NFAIL
NFAIL is INTEGER array, dimension (3) NFAIL(1) = No. of times residual STRSYL exceeds threshold THRESH NFAIL(2) = No. of times residual STRSYL3 exceeds threshold THRESH NFAIL(3) = No. of times STRSYL3 and STRSYL deviate
RMAX
RMAX is REAL, dimension (2) RMAX(1) = Value of the largest test ratio of STRSYL RMAX(2) = Value of the largest test ratio of STRSYL3
NINFO
NINFO is INTEGER array, dimension (2) NINFO(1) = No. of times STRSYL returns an expected INFO NINFO(2) = No. of times STRSYL3 returns an expected INFO
KNT
KNT is INTEGER Total number of examples tested.
Definition at line 88 of file ssyl01.f.
Author
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