Fix issue #45:out of range bug

[WWWonderer]

See issue #45.

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[carlini]

Your explanation and fix make sense to me. But I've been bitten enough times by "looks correct"....

Let me run a test on one of my ~10TB datasets just to make sure I get the same results before and after to make sure though. This shouldn't take too long, I'll post and update here when it finishes.

[WWWonderer]

Hi Nicholas, ok thank you!

[carlini]

I've confirmed this doesn't change results on my test case. Thanks, merged!

[WWWonderer]

Thank you so much!