kernel: optimize LcmInt for small inputs #2159
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fingolfin
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topic: performance
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Codecov Report
@@ Coverage Diff @@
## master #2159 +/- ##
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+ Coverage 68.34% 69.57% +1.22%
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Files 481 483 +2
Lines 254474 256113 +1639
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+ Hits 173927 178186 +4259
+ Misses 80547 77927 -2620
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This gives a tiny speed boost, but more importantly, avoids unnecessary allocation of temporary memory Before: gap> for i in [1..10000000] do LcmInt(2^50*13, 2^50*17); od; time; 2655 gap> for i in [1..10000000] do LcmInt(2^60*13, 2^60*17); od; time; 4450 gap> for i in [1..10000000] do LcmInt(2^70*13, 2^70*17); od; time; 5831 After: gap> for i in [1..10000000] do LcmInt(2^50*13, 2^50*17); od; time; 2381 gap> for i in [1..10000000] do LcmInt(2^60*13, 2^60*17); od; time; 4505 gap> for i in [1..10000000] do LcmInt(2^70*13, 2^70*17); od; time; 5854
rbehrends
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Feb 9, 2018
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Just for the kicks, this is what I get in GAP 4.8 (of course most of the speed up is due to @markuspf work on |
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Motivated by PR #2154 (which made me realize that
LcmInt(100, 1)will allocate a temporaryT_INTPOSobject only to immediately discard it again), this PR gives a tiny speed boost, but more importantly, avoids unnecessary allocation of temporary memory.Before:
After: