OK guys, this is funny....
I have nested DO LOOP:
PROGRAM RBX
IMPLICIT REAL*8 (A-H,O-Z) !variables that start with letter a,b,c,d,e,f,g,h,o,p,q,r,t,s,... are doubles
DO 1 I=1,5,1
DO 2 J=1,10,1
Z(I,J)=(some very complicated mathematics)
WRITE(*,*) Z(I,J)
2 CONTINUE
1 CONTINUE
END PROGRAM...