125 SUBROUTINE stbt06( RCOND, RCONDC, UPLO, DIAG, N, KD, AB, LDAB,
136 REAL rat, rcond, rcondc
139 REAL ab( ldab, * ), work( * )
146 parameter( zero = 0.0e+0, one = 1.0e+0 )
149 REAL anorm, bignum, eps, rmax, rmin, smlnum
164 rmax = max( rcond, rcondc )
165 rmin = min( rcond, rcondc )
169 IF( rmin.LT.zero )
THEN
175 ELSE IF( rmin.GT.zero )
THEN
179 rat = rmax / rmin - one
181 ELSE IF( rmax.EQ.zero )
THEN
195 smlnum =
slamch(
'Safe minimum' )
196 bignum = one / smlnum
197 CALL
slabad( smlnum, bignum )
198 anorm =
slantb(
'M', uplo, diag, n, kd, ab, ldab, work )
200 rat = rmax*( min( bignum / max( one, anorm ), one / eps ) )
REAL function slamch(CMACH)
SLAMCH
subroutine stbt06(RCOND, RCONDC, UPLO, DIAG, N, KD, AB, LDAB, WORK, RAT)
STBT06
subroutine slabad(SMALL, LARGE)
SLABAD
REAL function slantb(NORM, UPLO, DIAG, N, K, AB, LDAB, WORK)
SLANTB returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a triangular band matrix.