while loop and nan causing inifinite loop

I have the following code

now what happens when i run this is that the while loop doesn't ever stop and op ends up equal to (NaN NaN). i'm not exactly sure what's wrong.

i figured that i could simply try to exit the while loop if the value was nan by sayign that if np(1) or np(2) was equal to nan than np(1) would equal fp(1) and the while loop would stop, but i can't seem to do that either... could anyoen help me?

Answer 1

[Walter Roberson]

use isnan() to test for nan. Do not compare to nan using "=" or "~="

By the way, it appears to me that you should perhaps use atan2() instead of the tan() and range tests you have.

Answer 2

[Matt J]

Use the dbstop command

 >>dbstop if naninf

to detect where the NaNs are introduced.