JuliaDiff / JuliaDiff/ForwardDiff.jl

Provide way to specify which partial derivatives are computed for sparse Jacobians and Hessians

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Dominant language
Julia
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Description

It would be useful for JuMP to have a method to compute jacobian-vector and jacobian-matrix products. The current approach for computing jacobians can be interpreted as a jacobian-matrix products with the identity matrix.

Here's the implementation in ReverseDiffSparse: https://github.com/mlubin/ReverseDiffSparse.jl/blob/2530b758bb341d3c51e8c1195134922193e1cfb2/src/hessian.jl#L231

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Research direction

Start by reading the linked ReverseDiffSparse implementation in src/hessian.jl, especially around line 231, and compare it with ForwardDiff.jl's current Jacobian and Hessian computation entry points. Define the desired interface for selecting partial derivatives and for Jacobian-vector and Jacobian-matrix products, then add coverage showing that the selected products are computed correctly.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
tooling
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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