161 SUBROUTINE dtpt03( UPLO, TRANS, DIAG, N, NRHS, AP, SCALE, CNORM,
162 $ tscal, x, ldx, b, ldb, work, resid )
170 CHARACTER DIAG, TRANS, UPLO
171 INTEGER LDB, LDX, N, NRHS
172 DOUBLE PRECISION RESID, SCALE, TSCAL
175 DOUBLE PRECISION AP( * ), B( ldb, * ), CNORM( * ), WORK( * ),
182 DOUBLE PRECISION ONE, ZERO
183 parameter( one = 1.0d+0, zero = 0.0d+0 )
187 DOUBLE PRECISION BIGNUM, EPS, ERR, SMLNUM, TNORM, XNORM, XSCAL
192 DOUBLE PRECISION DLAMCH
193 EXTERNAL lsame, idamax, dlamch
199 INTRINSIC abs, dble, max
205 IF( n.LE.0 .OR. nrhs.LE.0 )
THEN
209 eps = dlamch(
'Epsilon' )
210 smlnum = dlamch(
'Safe minimum' )
211 bignum = one / smlnum
212 CALL
dlabad( smlnum, bignum )
218 IF( lsame( diag,
'N' ) )
THEN
219 IF( lsame( uplo,
'U' ) )
THEN
222 tnorm = max( tnorm, tscal*abs( ap( jj ) )+cnorm( j ) )
228 tnorm = max( tnorm, tscal*abs( ap( jj ) )+cnorm( j ) )
234 tnorm = max( tnorm, tscal+cnorm( j ) )
243 CALL
dcopy( n, x( 1, j ), 1, work, 1 )
244 ix = idamax( n, work, 1 )
245 xnorm = max( one, abs( x( ix, j ) ) )
246 xscal = ( one / xnorm ) / dble( n )
247 CALL
dscal( n, xscal, work, 1 )
248 CALL
dtpmv( uplo, trans, diag, n, ap, work, 1 )
249 CALL
daxpy( n, -scale*xscal, b( 1, j ), 1, work, 1 )
250 ix = idamax( n, work, 1 )
251 err = tscal*abs( work( ix ) )
252 ix = idamax( n, x( 1, j ), 1 )
253 xnorm = abs( x( ix, j ) )
254 IF( err*smlnum.LE.xnorm )
THEN
261 IF( err*smlnum.LE.tnorm )
THEN
268 resid = max( resid, err )
subroutine dcopy(N, DX, INCX, DY, INCY)
DCOPY
subroutine dlabad(SMALL, LARGE)
DLABAD
subroutine dscal(N, DA, DX, INCX)
DSCAL
subroutine dtpmv(UPLO, TRANS, DIAG, N, AP, X, INCX)
DTPMV
subroutine dtpt03(UPLO, TRANS, DIAG, N, NRHS, AP, SCALE, CNORM, TSCAL, X, LDX, B, LDB, WORK, RESID)
DTPT03
subroutine daxpy(N, DA, DX, INCX, DY, INCY)
DAXPY