Merge dense MLEs & update documentation #763
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The resulting polynomial is in 1 variable only, no need to index it
mmagician
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Pratyush and
weikengchen
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| let num_vars = log2(next_pow_of_two); | ||
| let mut evaluations: Vec<F> = Vec::with_capacity(next_pow_of_two); | ||
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| for poly in polys { |
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Isn't it better to limit ourselves to merging
This way, evaluating the merged polynomial at
Now, we cannot guarantee such meaning for the merged polynomial.
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The behavior is well defined when you pad with zeros, see the test case for unequal polys.
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Indeed it is well-defined in code, I see. I mean what is the meaning of the unequal case?
EDIT: Maybe the question is not relevant here. Never mind.
| /// let eval_combined = mle.evaluate(&point); | ||
| /// | ||
| /// assert_eq!(eval_combined, (Fr::one() - point[2]) * eval_1 + point[2] * eval_2); | ||
| pub fn merge(polys: impl IntoIterator<Item = impl AsRef<Self>> + Clone) -> Self { |
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What is the use case for this function? When would I want to concatenate two polynomials?
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For example in the case of committing to polynomials, instead of committing to 2^r different x-variate polynomials, one can commit to their merged polynomial which is (r+x)-variate polynomial (which can be faster depending on the scheme).
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This is something we could also use in our ark-spartan repo: https://github.com/arkworks-rs/spartan/blob/762fc57774fe70386532199911dd0955d58109e2/src/sparse_mlpoly.rs#L58
(will ofc require a larger refactor to switch from a custom DensePoly to one from ark-poly)
Description
Adapted from https://github.com/a16z/Lasso/blob/570831e6d9347c500e8397227647c4d71190ceaa/jolt-core/src/poly/dense_mlpoly.rs#L401
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