TESTING/EIG/dget31.f(3) | Library Functions Manual | TESTING/EIG/dget31.f(3) |
NAME
TESTING/EIG/dget31.f
SYNOPSIS
Functions/Subroutines
subroutine dget31 (rmax, lmax, ninfo, knt)
DGET31
Function/Subroutine Documentation
subroutine dget31 (double precision rmax, integer lmax, integer, dimension( 2 ) ninfo, integer knt)
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.
Author
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