FUNCTION BILIN (z, ni, nj, x, y, OK)

ARGUMENTS

OUT

OK        OK iff indexes are in limits of the field Z   
          (initialization:.true., else returns .false.) logical

IN

Z(NI,NJ)  field on which the computation is done        real
NI        x-dimension of array Z                        integer
NJ        y-dimension of array Z                        integer
X         x-coordinate of the point to compute          real
Y         y-coordinate of the point to compute          real
 (1,NJ)      (NI,NJ)
   +-------------+
   |             | 
   |             |  array Z 
   |             |
   |  *(X,Y)     |
   |             |
   +-------------+
  (1,1)       (NI,1)

DESCRIPTION

EXAMPLE