subroutine dget31 (rmax, lmax, ninfo, knt)
DGET31
DGET31
Purpose:
DGET31 tests DLALN2, a routine for solving
(ca A - w D)X = sB
where A is an NA by NA matrix (NA=1 or 2 only), w is a real (NW=1) or
complex (NW=2) constant, ca is a real constant, D is an NA by NA real
diagonal matrix, and B is an NA by NW matrix (when NW=2 the second
column of B contains the imaginary part of the solution). The code
returns X and s, where s is a scale factor, less than or equal to 1,
which is chosen to avoid overflow in X.
If any singular values of ca A-w D are less than another input
parameter SMIN, they are perturbed up to SMIN.
The test condition is that the scaled residual
norm( (ca A-w D)*X - s*B ) /
( max( ulp*norm(ca A-w D), SMIN )*norm(X) )
should be on the order of 1. Here, ulp is the machine precision.
Also, it is verified that SCALE is less than or equal to 1, and that
XNORM = infinity-norm(X).
Parameters
RMAX
RMAX is DOUBLE PRECISION
Value of the largest test ratio.
LMAX
LMAX is INTEGER
Example number where largest test ratio achieved.
NINFO
NINFO is INTEGER array, dimension (2)
NINFO(1) = number of examples with INFO less than 0
NINFO(2) = number of examples with INFO greater than 0
KNT
KNT is INTEGER
Total number of examples tested.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 90 of file dget31.f.
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