Lost in Translation

I've been having this problem that when I run my 3D auto-correlation function code on my laptop it runs fine, and gives me a logical result, but when I run the same code on my LBNL machine (riemann, for those who are familiar) I get a Segmentation fault and the code crashes. The code has the same inputs for both machines. The scarier thing is that when I run the code on a file with more data points, it doesn't crash on either machine.

However, I'm supposed to write about research accomplishments, so let me show the autocorrelation functions of the files that DID run:

3D auto-correlation function

2D cross-correlation function

I think the problem is that the files which are crashing have so few data points that there are some correlation bins where there are no objects separated by that distance. I am not actually sure how the code handles this. I would hope that it would just set that bin to zero, but there is quite likely a divide by zero problem going on here. Time to insert some print statements and get to the root of this.