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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
|
| subroutine ssyl01 | ( | real | thresh, |
| integer, dimension( 3 ) | nfail, | ||
| real, dimension( 2 ) | rmax, | ||
| integer, dimension( 2 ) | ninfo, | ||
| integer | knt | ||
| ) |
SSYL01
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. | [in] | THRESH | THRESH is REAL
A test will count as "failed" if the residual, computed as
described above, exceeds THRESH. |
| [out] | 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 |
| [out] | 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 |
| [out] | 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 |
| [out] | KNT | KNT is INTEGER
Total number of examples tested. |