Avoid large intermediate product in LCM #350
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Hmm, Travis has this failing on nightly but the error is rather mysterious and doesn't seem related to my change. |
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Don't worry, the build is failing because the |
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Ugh, num-macros... I'm inclined to finally let that die. This PR is good though -- we already did similar to avoid overflowing primitives in #167. |
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#351 nuked num-macros, so let's give this a try: bors r+ |
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Dec 14, 2017
350: Avoid large intermediate product in LCM r=cuviper a=mhogrefe Changed the implementation of BigUint LCM from `((self * other) / self.gcd(other))` to `self / self.gcd(other) * other` The division is exact in both cases, so the result is the same, but the new code avoids the potentially-large intermediate product, speeding things up and using less memory. I also removed the unnecessary parentheses, because I think it's clear what order everything will be executed in. But if others think differently I can add them back.
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Changed the implementation of BigUint LCM from
((self * other) / self.gcd(other))to
self / self.gcd(other) * otherThe division is exact in both cases, so the result is the same, but the new code avoids the potentially-large intermediate product, speeding things up and using less memory.
I also removed the unnecessary parentheses, because I think it's clear what order everything will be executed in. But if others think differently I can add them back.