111 SUBROUTINE sbdt02( M, N, B, LDB, C, LDC, U, LDU, WORK, RESID )
118 INTEGER LDB, LDC, LDU, M, N
122 REAL B( LDB, * ), C( LDC, * ), U( LDU, * ),
130 parameter( zero = 0.0e+0, one = 1.0e+0 )
134 REAL BNORM, EPS, REALMN
137 REAL SASUM, SLAMCH, SLANGE
138 EXTERNAL sasum, slamch, slange
144 INTRINSIC max, min, real
151 IF( m.LE.0 .OR. n.LE.0 )
153 realmn = real( max( m, n ) )
154 eps = slamch(
'Precision' )
159 CALL scopy( m, b( 1, j ), 1, work, 1 )
160 CALL sgemv(
'No transpose', m, m, -one, u, ldu, c( 1, j ), 1,
162 resid = max( resid, sasum( m, work, 1 ) )
167 bnorm = slange(
'1', m, n, b, ldb, work )
169 IF( bnorm.LE.zero )
THEN
173 IF( bnorm.GE.resid )
THEN
174 resid = ( resid / bnorm ) / ( realmn*eps )
176 IF( bnorm.LT.one )
THEN
177 resid = ( min( resid, realmn*bnorm ) / bnorm ) /
180 resid = min( resid / bnorm, realmn ) / ( realmn*eps )
subroutine sgemv(trans, m, n, alpha, a, lda, x, incx, beta, y, incy)
SGEMV
subroutine sbdt02(m, n, b, ldb, c, ldc, u, ldu, work, resid)
SBDT02