Fortran frozen after iterations in a loop

Hi,

The code I have attached is freezen at the 204th loop. 

I have no idea the reason for that. 

When I set the parameter nr=100, everything works fine, and when I set nr=500, the code freezes at the 1275th loop.

Since I am new at this, could anyone provide me any help?

I am using Intel(R) Visual Fortran Intel(R) 64 Compiler XE on Intel(R) 64, version 12.1.2 , with IMSL 6.0

Thank you very much!

Pedro