TESTING/EIG/zsyl01.f(3) | Library Functions Manual | TESTING/EIG/zsyl01.f(3) |
NAME
TESTING/EIG/zsyl01.f
SYNOPSIS
Functions/Subroutines
subroutine zsyl01 (thresh, nfail, rmax, ninfo, knt)
ZSYL01
Function/Subroutine Documentation
subroutine zsyl01 (double precision thresh, integer, dimension( 3 ) nfail, double precision, dimension( 2 ) rmax, integer, dimension( 2 ) ninfo, integer knt)
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.
Author
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