124 REAL FUNCTION slangb( NORM, N, KL, KU, AB, LDAB,
134 INTEGER KL, KU, LDAB, N
137 REAL AB( ldab, * ), WORK( * )
145 parameter ( one = 1.0e+0, zero = 0.0e+0 )
149 REAL SCALE, SUM,
VALUE, TEMP
155 LOGICAL LSAME, SISNAN
156 EXTERNAL lsame, sisnan
159 INTRINSIC abs, max, min, sqrt
165 ELSE IF( lsame( norm,
'M' ) )
THEN
171 DO 10 i = max( ku+2-j, 1 ), min( n+ku+1-j, kl+ku+1 )
172 temp = abs( ab( i, j ) )
173 IF(
VALUE.LT.temp .OR. sisnan( temp ) )
VALUE = temp
176 ELSE IF( ( lsame( norm,
'O' ) ) .OR. ( norm.EQ.
'1' ) )
THEN
183 DO 30 i = max( ku+2-j, 1 ), min( n+ku+1-j, kl+ku+1 )
184 sum = sum + abs( ab( i, j ) )
186 IF(
VALUE.LT.sum .OR. sisnan( sum ) )
VALUE = sum
188 ELSE IF( lsame( norm,
'I' ) )
THEN
197 DO 60 i = max( 1, j-ku ), min( n, j+kl )
198 work( i ) = work( i ) + abs( ab( k+i, j ) )
204 IF(
VALUE.LT.temp .OR. sisnan( temp ) )
VALUE = temp
206 ELSE IF( ( lsame( norm,
'F' ) ) .OR. ( lsame( norm,
'E' ) ) )
THEN
215 CALL slassq( min( n, j+kl )-l+1, ab( k, j ), 1, scale, sum )
217 VALUE = scale*sqrt( sum )
real function slangb(NORM, N, KL, KU, AB, LDAB, WORK)
SLANGB returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value ...
subroutine slassq(N, X, INCX, SCALE, SUMSQ)
SLASSQ updates a sum of squares represented in scaled form.