Hi to all. I am programing a new code for some calculation and i have detected a strange issue. I have my all arrays strictly defined for example real, dimension(-2:2,-3:2) A, B complex, dimension(-2:2,1:2) C In my time dependend calculations i expect the matrix element C(-2,1) to have a maximum value during the whole run, to be approximately about 1.5 and if you attempt the plot t vs C(-2,1) then the curve seems like a Gaussian. While i use the ifort and gfortran compilers, i attempted an "experiment" to write the matrix element C(-3,1) (which is NOT defined anywhere initialy in my program... because i have complex, dimension(-2:2,1:2) C and not complex, dimension(-3:2,1:2) C) The i i descovered that if i plot t vs C(-3,1) then the curve i get is a similar to t vs C(-2,1) which is completely strange because is not defined anywhere so i expect to have zero value every time. I repeat, every array in my program has been defined bounds as i shown above. How does it happen??