module laplac2 {                                    # Laplacian operator in 2-D
use igrad2
logical, parameter, private  :: T = .true., F = .false.
real, dimension (m1*m2*2), allocatable :: tmp
#%_init    (m1, m2)
    integer m1, m2
    call igrad2_init (m1, m2)
#%_lop (x, y)
    integer stat1, stat2
    if( adj) {
    	stat1 = igrad2_lop (  F,    F, y, tmp)   # tmp = grad y
    	stat2 = igrad2_lop (  T,  add, x, tmp)   # x = x + grad' tmp
    } else   {
	stat1 = igrad2_lop (  F,    F, x, tmp)   # tmp = grad x
    	stat2 = igrad2_lop (  T,  add, y, tmp)   # y = y + grad' tmp
    }
}