141 DOUBLE PRECISION FUNCTION zlantb( NORM, UPLO, DIAG, N, K, AB,
150 CHARACTER diag, norm, uplo
154 DOUBLE PRECISION work( * )
155 COMPLEX*16 ab( ldab, * )
161 DOUBLE PRECISION one, zero
162 parameter( one = 1.0d+0, zero = 0.0d+0 )
167 DOUBLE PRECISION scale, sum,
value
177 INTRINSIC abs, max, min, sqrt
183 ELSE IF(
lsame( norm,
'M' ) )
THEN
187 IF(
lsame( diag,
'U' ) )
THEN
189 IF(
lsame( uplo,
'U' ) )
THEN
191 DO 10 i = max( k+2-
j, 1 ), k
192 sum = abs( ab( i,
j ) )
198 DO 30 i = 2, min( n+1-
j, k+1 )
199 sum = abs( ab( i,
j ) )
206 IF(
lsame( uplo,
'U' ) )
THEN
208 DO 50 i = max( k+2-
j, 1 ), k + 1
209 sum = abs( ab( i,
j ) )
215 DO 70 i = 1, min( n+1-
j, k+1 )
216 sum = abs( ab( i,
j ) )
222 ELSE IF( (
lsame( norm,
'O' ) ) .OR. ( norm.EQ.
'1' ) )
THEN
227 udiag =
lsame( diag,
'U' )
228 IF(
lsame( uplo,
'U' ) )
THEN
232 DO 90 i = max( k+2-
j, 1 ), k
233 sum = sum + abs( ab( i,
j ) )
237 DO 100 i = max( k+2-
j, 1 ), k + 1
238 sum = sum + abs( ab( i,
j ) )
247 DO 120 i = 2, min( n+1-
j, k+1 )
248 sum = sum + abs( ab( i,
j ) )
252 DO 130 i = 1, min( n+1-
j, k+1 )
253 sum = sum + abs( ab( i,
j ) )
259 ELSE IF(
lsame( norm,
'I' ) )
THEN
264 IF(
lsame( uplo,
'U' ) )
THEN
265 IF(
lsame( diag,
'U' ) )
THEN
271 DO 160 i = max( 1,
j-k ),
j - 1
272 work( i ) = work( i ) + abs( ab( l+i,
j ) )
281 DO 190 i = max( 1,
j-k ),
j
282 work( i ) = work( i ) + abs( ab( l+i,
j ) )
287 IF(
lsame( diag,
'U' ) )
THEN
293 DO 220 i =
j + 1, min( n,
j+k )
294 work( i ) = work( i ) + abs( ab( l+i,
j ) )
303 DO 250 i =
j, min( n,
j+k )
304 work( i ) = work( i ) + abs( ab( l+i,
j ) )
313 ELSE IF( (
lsame( norm,
'F' ) ) .OR. (
lsame( norm,
'E' ) ) )
THEN
317 IF(
lsame( uplo,
'U' ) )
THEN
318 IF(
lsame( diag,
'U' ) )
THEN
324 $ ab( max( k+2-
j, 1 ),
j ), 1, scale,
332 CALL
zlassq( min(
j, k+1 ), ab( max( k+2-
j, 1 ),
j ),
337 IF(
lsame( diag,
'U' ) )
THEN
342 CALL
zlassq( min( n-
j, k ), ab( 2,
j ), 1, scale,
350 CALL
zlassq( min( n-
j+1, k+1 ), ab( 1,
j ), 1, scale,
355 value = scale*sqrt( sum )
double precision function zlantb(NORM, UPLO, DIAG, N, K, AB, LDAB, WORK)
ZLANTB 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.
subroutine zlassq(N, X, INCX, SCALE, SUMSQ)
ZLASSQ updates a sum of squares represented in scaled form.
input scalars passed by value
logical function lsame(CA, CB)
LSAME
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real j
logical function disnan(DIN)
DISNAN tests input for NaN.