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.
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