171 SUBROUTINE cpbt05( UPLO, N, KD, NRHS, AB, LDAB, B, LDB, X, LDX,
172 $ xact, ldxact, ferr, berr, reslts )
181 INTEGER kd, ldab, ldb, ldx, ldxact, n, nrhs
184 REAL berr( * ), ferr( * ), reslts( * )
185 COMPLEX ab( ldab, * ),
b( ldb, * ),
x( ldx, * ),
193 parameter( zero = 0.0e+0, one = 1.0e+0 )
197 INTEGER i, imax,
j, k, nz
198 REAL axbi, diff, eps, errbnd, ovfl, tmp, unfl, xnorm
208 INTRINSIC abs, aimag, max, min, real
214 cabs1( zdum ) = abs(
REAL( ZDUM ) ) + abs( aimag( zdum ) )
220 IF( n.LE.0 .OR. nrhs.LE.0 )
THEN
227 unfl =
slamch(
'Safe minimum' )
229 upper =
lsame( uplo,
'U' )
230 nz = 2*max( kd, n-1 ) + 1
239 xnorm = max( cabs1(
x( imax,
j ) ), unfl )
242 diff = max( diff, cabs1(
x( i,
j )-xact( i,
j ) ) )
245 IF( xnorm.GT.one )
THEN
247 ELSE IF( diff.LE.ovfl*xnorm )
THEN
255 IF( diff / xnorm.LE.ferr(
j ) )
THEN
256 errbnd = max( errbnd, ( diff / xnorm ) / ferr(
j ) )
268 tmp = cabs1(
b( i, k ) )
270 DO 40
j = max( i-kd, 1 ), i - 1
271 tmp = tmp + cabs1( ab( kd+1-i+
j, i ) )*
274 tmp = tmp + abs(
REAL( AB( KD+1, I ) ) )*
276 DO 50
j = i + 1, min( i+kd, n )
277 tmp = tmp + cabs1( ab( kd+1+i-
j,
j ) )*
281 DO 60
j = max( i-kd, 1 ), i - 1
282 tmp = tmp + cabs1( ab( 1+i-
j,
j ) )*cabs1(
x(
j, k ) )
284 tmp = tmp + abs(
REAL( AB( 1, I ) ) )*cabs1(
x( i, k ) )
285 DO 70
j = i + 1, min( i+kd, n )
286 tmp = tmp + cabs1( ab( 1+
j-i, i ) )*cabs1(
x(
j, k ) )
292 axbi = min( axbi, tmp )
295 tmp = berr( k ) / ( nz*eps+nz*unfl / max( axbi, nz*unfl ) )
299 reslts( 2 ) = max( reslts( 2 ), tmp )
LOGICAL function lsame(CA, CB)
LSAME
REAL function slamch(CMACH)
SLAMCH
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real b(3) integer i
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real j
subroutine cpbt05(UPLO, N, KD, NRHS, AB, LDAB, B, LDB, X, LDX, XACT, LDXACT, FERR, BERR, RESLTS)
CPBT05
INTEGER function icamax(N, CX, INCX)
ICAMAX