fix(simplify): Improve collection of nonconstant like terms#2384
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josdejong merged 2 commits intoJan 15, 2022
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The key is that the rule-matching engine is optimized for finding matches on the lefts of terms, but the central term-collection rule `n1*n3 + n2*n3 -> (n1+n2)*n3` was written with the key common term rightmost. Reversing this rule to `n3*n1 + n3*n2 -> n3*(n1+n2)` therefore does most of the work of improving like-term collection. It also better corresponds to typical mathematical presentation: common terms tend to be pulled out to the left in common practice. Floating constants to the right of a product initially (before they are moved back to the left for human-preferred output) and ensuring that negations are subsumed into constants whenever possible did the rest. Also, rule context was not being propagated into the simplification engine; this commit corrects that. Resolves josdejong#1179. Resolves josdejong#1290.
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Thanks Glen. This is a set of neat improvements and fixes 👍👍 |
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The key is that the rule-matching engine is optimized for finding matches
on the lefts of terms, but the central term-collection rule
n1*n3 + n2*n3 -> (n1+n2)*n3was written with the key common term rightmost.Reversing this rule to
n3*n1 + n3*n2 -> n3*(n1+n2)therefore does mostof the work of improving like-term collection. It also better corresponds
to typical mathematical presentation: common terms tend to be pulled out
to the left in practice.
Floating constants to the right of a product initially (before they are
moved back to the left for human-preferred output) and ensuring that
negations are subsumed into constants whenever possible did the rest.
Also, rule context was not being propagated into the simplification
engine; this commit corrects that.
Resolves #1179.
Resolves #1290.
I also have a succinct PR for #1423 in a similar spirit that depends on this which I will be happy to submit should this be approved (perhaps with revisions) and merged.