subroutine srotg(sa,sb,c,s) c c construct givens plane rotation. c jack dongarra, linpack, 3/11/78. c real sa,sb,c,s,roe,scale,r,z c roe = sb if( abs(sa) .gt. abs(sb) ) roe = sa scale = abs(sa) + abs(sb) if( scale .ne. 0.0 ) go to 10 c = 1.0 s = 0.0 r = 0.0 z = 0.0 go to 20 10 r = scale*sqrt((sa/scale)**2 + (sb/scale)**2) r = sign(1.0,roe)*r c = sa/r s = sb/r z = 1.0 if( abs(sa) .gt. abs(sb) ) z = s if( abs(sb) .ge. abs(sa) .and. c .ne. 0.0 ) z = 1.0/c 20 sa = r sb = z return end