subroutine sget39 (rmax, lmax, ninfo, knt)
SGET39
SGET39
Purpose:
SGET39 tests SLAQTR, a routine for solving the real or
special complex quasi upper triangular system
op(T)*p = scale*c,
or
op(T + iB)*(p+iq) = scale*(c+id),
in real arithmetic. T is upper quasi-triangular.
If it is complex, then the first diagonal block of T must be
1 by 1, B has the special structure
B = [ b(1) b(2) ... b(n) ]
[ w ]
[ w ]
[ . ]
[ w ]
op(A) = A or A', where A' denotes the conjugate transpose of
the matrix A.
On input, X = [ c ]. On output, X = [ p ].
[ d ] [ q ]
Scale is an output less than or equal to 1, chosen to avoid
overflow in X.
This subroutine is specially designed for the condition number
estimation in the eigenproblem routine STRSNA.
The test code verifies that the following residual is order 1:
||(T+i*B)*(x1+i*x2) - scale*(d1+i*d2)||
-----------------------------------------
max(ulp*(||T||+||B||)*(||x1||+||x2||),
(||T||+||B||)*smlnum/ulp,
smlnum)
(The (||T||+||B||)*smlnum/ulp term accounts for possible
(gradual or nongradual) underflow in x1 and x2.)
Parameters
RMAX
RMAX is REAL
Value of the largest test ratio.
LMAX
LMAX is INTEGER
Example number where largest test ratio achieved.
NINFO
NINFO is INTEGER
Number of examples where INFO is nonzero.
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 102 of file sget39.f.
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