105 SUBROUTINE dptt02( N, NRHS, D, E, X, LDX, B, LDB, RESID )
113 INTEGER ldb, ldx, n, nrhs
114 DOUBLE PRECISION resid
117 DOUBLE PRECISION b( ldb, * ), d( * ), e( * ),
x( ldx, * )
123 DOUBLE PRECISION one, zero
124 parameter( one = 1.0d+0, zero = 0.0d+0 )
128 DOUBLE PRECISION anorm, bnorm, eps, xnorm
151 anorm =
dlanst(
'1', n, d, e )
156 IF( anorm.LE.zero )
THEN
163 CALL
dlaptm( n, nrhs, -one, d, e,
x, ldx, one,
b, ldb )
170 bnorm =
dasum( n,
b( 1,
j ), 1 )
171 xnorm =
dasum( n,
x( 1,
j ), 1 )
172 IF( xnorm.LE.zero )
THEN
175 resid = max( resid, ( ( bnorm / anorm ) / xnorm ) / eps )
DOUBLE PRECISION function dlanst(NORM, N, D, E)
DLANST returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric tridiagonal matrix.
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real b(3) integer i
subroutine dptt02(N, NRHS, D, E, X, LDX, B, LDB, RESID)
DPTT02
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real j
DOUBLE PRECISION function dlamch(CMACH)
DLAMCH
DOUBLE PRECISION function dasum(N, DX, INCX)
DASUM
subroutine dlaptm(N, NRHS, ALPHA, D, E, X, LDX, BETA, B, LDB)
DLAPTM