Hook for custom solve against mass matrix for explicit time integrators#30
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mhodzelmans wants to merge 6 commits into
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Hook for custom solve against mass matrix for explicit time integrators#30mhodzelmans wants to merge 6 commits into
mhodzelmans wants to merge 6 commits into
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Pull request overview
This PR introduces an extensible “mass inverse” hook for explicit dynamic time integrators so they can apply (M^{-1}) via a reusable solve/factorization instead of explicitly forming and multiplying by a stored inverse.
Changes:
- Add
gsDynamicMassInversefunction-object interface with default explicit-inverse and a sparse-solver-backed implementation. - Update Explicit Euler and RK4 to use
_applyMassInverse(time, rhs, result)instead of explicitly formingMinv. - Update
gsDynamicBaseto own/cache a mass-inverse object and expose setters for custom implementations.
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.
| File | Description |
|---|---|
| src/gsDynamicSolvers/gsDynamicRK4.hpp | Switch RK4 acceleration computation to _applyMassInverse(...); also changes RK4 stage-4 evaluation time/state. |
| src/gsDynamicSolvers/gsDynamicMassInverse.h | New mass-inverse function-object interface plus explicit-inverse and sparse-solver-backed implementations. |
| src/gsDynamicSolvers/gsDynamicExplicitEuler.hpp | Switch Explicit Euler acceleration computation to _applyMassInverse(...). |
| src/gsDynamicSolvers/gsDynamicBase.h | Add mass-inverse ownership/caching, time-dependence handling, and setters to customize inverse/solve strategy. |
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…xplicit inversion.
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| void compute(const gsSparseMatrix<T> & mass) | ||
| { | ||
| gsSparseMatrix<T> eye(mass.rows(), mass.cols()); | ||
| eye.setIdentity(); | ||
| typename gsSparseSolver<T>::LU solver(mass); | ||
| gsMatrix<T> inverse = solver.solve(eye); | ||
| m_massInv = inverse.sparseView(); | ||
| } | ||
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| void apply(const gsVector<T> & rhs, gsVector<T> & result) const | ||
| { | ||
| result = m_massInv * rhs; | ||
| } |
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Don't bother checking for square mass
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
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| void apply(const gsVector<T> & rhs, gsVector<T> & result) const override | ||
| { | ||
| result = m_solver->solve(rhs); | ||
| } |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
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The existing RK4 and explicit euler method compute the inverse of the mass matrix, then reuse that for computing accelerations. This is inefficient. Generally, a factorization we solve against is faster.
This patch introduces a virtual class / function object containing the functionality to solve against the mass matrix. i.e. a compute step for caching, and a solve step. The dynamicBase owns one of these. It's defaulted to the pre-existing explicit inverse. Setters are available now for custom things. One function object using standard Eigen LDLT is added.