ML: Inference speedup

Machine-learning ideas tagged Inference speedup in the ML taxonomy of the Math2NN corpus.

✓✓ Beats tuned baseline 2026

Posterior-Routed Low-Rank Diffusion Experts

Use the noisy diffusion state to estimate posterior probabilities over data clusters, then route the denoising computation to one or a few cluster-specific score experts. Each expert stores a low-rank covariance or low-rank score correction, so after posterior commitment the denoiser operates at the cluster intrinsic dimension rather than ambient dimension. During the early mixing phase, retain a shared full-dimensional score or evaluate a small weighted set of experts.

Useful8/10
Difficulty6/10
Novelty6/10
Paper: Diffusion Models for High-Dimensional Clustered Data: Intrinsic-Dimension Adaptivity via Bayesian Classification arXiv:2608.19067
△ Mechanism confirmed, baseline not beaten 2026

Rate-adaptive KV-cache quantizer

Allocate different entropy budgets to different KV-cache blocks instead of assigning every token and head the same nominal bitwidth. Use the ECASQ Lagrangian so high-variance or attention-sensitive blocks receive more codepoints, while predictable blocks collapse to fewer symbols and become highly compressible. Preserve unbiasedness per scalar or block so reconstructed keys and values have zero mean quantization error conditional on the original tensor.

Useful8/10
Difficulty6/10
Novelty7/10
Paper: Entropy-Constrained Adaptive Stochastic Quantization arXiv:2608.18147
△ Mechanism confirmed, baseline not beaten 2026

Entropy-constrained unbiased block quantization

Replace fixed-grid stochastic quantization of each tensor block with an adaptive ordered codebook selected under both an entropy budget and a maximum number of codepoints. Within every interval between adjacent codepoints, use unbiased stochastic interpolation, so the quantized block remains unbiased while the emitted symbol distribution becomes easier for arithmetic or Huffman coding to compress. The representation should reduce actual compressed bytes at fixed MSE, or reduce MSE at fixed…

Useful8/10
Difficulty6/10
Novelty6/10
Paper: Entropy-Constrained Adaptive Stochastic Quantization arXiv:2608.18147
✗ Failed on benchmark 2026

Averaged Contractive State-Space Network

Construct a continuous-time SSM or neural ODE whose hidden-state dynamics use rapidly varying periodic parameters while enforcing contraction of the instantaneous Jacobian. In the high-frequency regime, replace the expensive oscillatory dynamics with an averaged SSM during long-horizon rollout; the averaging principle predicts finite-horizon trajectory convergence, while contraction predicts stable long-time behavior.

Useful8/10
Difficulty6/10
Novelty7/10
Paper: Averaging Principle and Pullback Attractor Convergence for McKean--Vlasov Stochastic Reaction--Diffusion Equations arXiv:2608.09319
✓✓ Beats tuned baseline 2026

Derivative-conditioned fine-scale corrector

Replace a full-resolution neural operator with an explicit multiscale reconstruction: a coarse predictor produces a low-resolution field, and a small corrector module combines its gradients and Hessians with learned rapidly varying basis functions. The model should recover fine detail without running the expensive backbone at fine resolution.

Useful8/10
Difficulty5/10
Novelty7/10
Paper: Efficient higher-order multi-scale method and its convergence estimate for dynamic nonlinear hygro-thermo-mechanical coupling problems of heterogeneous structures arXiv:2608.05580
△ Mechanism confirmed, baseline not beaten 2026

Recursive Butterfly Linear Layer

Replace a square dense projection in a Transformer or MLP with a trainable recursive butterfly matrix. The layer preserves multiscale channel interactions while constraining every complementary row-column block to rank at most k, reducing parameters and enabling recursive structured matrix-vector products. Unlike an arbitrary sparse layer, the construction has an explicit recursive factorization and a quasi-optimal approximation guarantee among matrices with the same butterfly rank.

Useful8/10
Difficulty6/10
Novelty5/10
Paper: A recursive butterfly factorization with optimality guarantees arXiv:2607.29361
✗ Failed on benchmark 2026

Equal-Volume KV Vector Quantization

Replace consecutive or randomly assigned transformed KV coefficients with groups whose variance-volume is approximately equal. Train one equal-size vector-quantizer codebook per group, so a fixed-width cache does not waste its low-rate budget by forcing high-variance and low-variance coordinates into badly mismatched groups. This is a drop-in quantization-layout change that can be applied to keys, values, or both.

Useful8/10
Difficulty5/10
Novelty7/10
Paper: Spend Bits Where Queries Look: KV Cache Vector Quantization with Attention-Preserving Transforms arXiv:2608.04074
△ Mechanism confirmed, baseline not beaten 2026

Sparse-Graph Tensorized Linear Layer

Replace a dense neural-network weight tensor with a graph tensor network whose physical modes and internal edge ranks are specified by a sparse rank-adjacency matrix. Unlike tensor-train or hierarchical Tucker layers, the graph can contain selected cycles and skip connections between tensor modes, allowing the factorization topology to match correlations in the weight tensor. Fit the layer with GTN-SVD at a prescribed tolerance and compare accuracy, parameter count, and tensor-contraction…

Useful8/10
Difficulty6/10
Novelty5/10
Paper: Computing with traceable tensor networks arXiv:2608.02849
△ Mechanism confirmed, baseline not beaten 2026

Dataset-adaptive unitary spectral codec

Replace a fixed DCT or Fourier transform in transform coding with a trainable isometric tensor-network transform whose local gates are learned once on a dataset. Retain the k coefficients with largest magnitude and reconstruct with the exact adjoint transform; the transform remains norm-preserving and fast while adapting its coefficient ordering to the data distribution.

Useful8/10
Difficulty5/10
Novelty7/10
Paper: Fast Trainable Multilinear Bases for Image Compression arXiv:2608.00053
△ Mechanism confirmed, baseline not beaten 2026

Compiled forward second-order jet residuals

Build a forward-mode second-order jet interpreter for the PINN and evaluate the entire PDE residual in one compiled graph. Each intermediate carries its value, first derivative, and Hessian with respect to the collocation coordinates, avoiding repeated nested reverse-mode autodiff calls for every residual component.

Useful8/10
Difficulty5/10
Novelty6/10
Paper: A user's guide to PINNs in geometric analysis: lessons from the asymptotic Plateau problem arXiv:2607.28733
✓✓ Beats tuned baseline 2026

Sublinear-expander sparse attention

Replace dense self-attention by a sparse attention graph whose neighborhoods satisfy the paper's size-dependent expansion condition. This preserves a logarithmically controlled route for every token subset to communicate with the rest of the sequence, reducing quadratic attention cost without allowing disconnected or poorly mixed token groups.

Useful8/10
Difficulty5/10
Novelty5/10
Paper: Recent progress in graph theory using expansion arXiv:2607.26049
△ Mechanism confirmed, baseline not beaten 2026

Log-Depth Chunked Linear-Attention Scan

Implement causal linear attention in chunks and combine chunk summaries with an associative scan instead of carrying the recurrent state through all chunks sequentially. This preserves the exact causal computation while reducing inter-chunk dependency depth from the number of chunks to its logarithm, enabling substantially more GPU parallelism for long-context training and prefill.

Useful8/10
Difficulty6/10
Novelty6/10
Paper: Kernelized Linear Attention: Breaking the Capacity Wall with Symmetric Cones arXiv:2607.17419
△ Mechanism confirmed, baseline not beaten 2026

Biclique-Hub Attention

Replace a dense directed attention matrix by a collection of K learned source-to-hub-to-target interactions. Each hub corresponds to a directed biclique, allowing many source tokens to communicate with many target tokens using O(NK) rather than O(N^2) pair interactions. The construction preserves asymmetric information flow and can be initialized from a graph cover of high-attention edges.

Useful8/10
Difficulty6/10
Novelty6/10
Paper: On Transformer Dynamics arXiv:2607.13295
△ Mechanism confirmed, baseline not beaten 2026

Joint Tucker-rank and residual-bit KV allocator

Compress each layer's KV tensor with a partial Tucker approximation over token and feature axes, then encode the truncation residual with a rotated uniform quantizer. Select token rank, feature rank, and residual bit-width jointly under a global byte budget, allowing values with flat spectra to receive residual bits while keys may receive more low-rank capacity.

Useful8/10
Difficulty6/10
Novelty6/10
Paper: A JoLT for the KV cache: Near-lossless KV cache compression via joint Lagrangian allocation of Tucker ranks and a rotated residual for llms arXiv:2607.12550
✗ Failed on benchmark 2026

Balanced State-Order Compression

Compress each hidden layer by retaining directions that are simultaneously reachable from the observed input distribution and observable at the network output. Unlike PCA or SVD, the retained subspace is weighted by downstream task sensitivity, so high-variance but output-irrelevant directions can be removed while low-variance predictive directions are preserved.

Useful8/10
Difficulty5/10
Novelty7/10
Paper: Empirical Minimal-Realisation Compression of Deep Neural Networks via Controllability-Observability Tests arXiv:2607.05457
✗ Failed on benchmark 2026

Derivative-Jet MLP Compression

Compress a trained wide analytic-activation MLP by fitting a narrow same-depth student to the teacher's function values and input derivatives, rather than matching only outputs on a calibration dataset. Choose the student width from the input dimension and target error, with a target scaling m = O((log(1/epsilon))^d_in), and use sequential layer fitting plus channel reweighting to limit error accumulation through depth.

Useful8/10
Difficulty6/10
Novelty7/10
Paper: Width-Independent Compressibility of Deep Neural Networks arXiv:2608.21752
△ Mechanism confirmed, baseline not beaten 2026

Utility-Weighted Left-Edge Quantization

Replace MSE-calibrated scalar quantization with a conservative left-edge quantizer whose thresholds are denser where activation probability and task utility slope are both high. For a monotone utility function, this should preserve high-impact activation regions better than uniform or MSE-optimal bins at the same number of codes, while retaining an explicit rate-versus-quality design rule.

Useful7/10
Difficulty4/10
Novelty7/10
Paper: A Quantization Problem Posed by Adaptive Streaming arXiv:2609.03745
✗ Mechanism failed 2026

Recorded-Mesh Neural ODE Backpropagation

Run an adaptive neural ODE solver once to determine accepted step sizes, then train using a regular fixed-length replay of those steps rather than differentiating through adaptive accept/reject logic. The replay can be fused across a batch of trajectories and differentiated with an ordinary reverse sweep, giving the exact discrete gradient of the replayed solver and predictable GPU work.

Useful7/10
Difficulty5/10
Novelty6/10
Paper: GRADSOLVE: fast exact gradients for ODE ensembles on GPUs arXiv:2609.02876
✗ Mechanism failed 2026

Polar Slack Attention

Use a spherical-design codebook and the paper's polar slack factorization to create a nonnegative geometric interaction bias for attention or expert routing. The resulting kernel is generated by a rank-one term and a rank-at-most-d term, and entries close to zero can define a structured sparse mask instead of relying only on learned top-k selection.

Useful7/10
Difficulty6/10
Novelty7/10
Paper: Dual Geometry of Spherical Designs: Polarity, Self-Polar Rigidity, and Quadrature Structure arXiv:2609.02439
✗ Mechanism failed 2026

Ranking-Aware Projection Dimension Rule

Replace the usual JL dimension choice with a task-specific dimension budget based on the paper's asymptotic ranking law. For retrieval, nearest-neighbor search, or compressed attention keys, choose m from a target Kendall correlation and automatically expand the projection when measured ranking quality falls below the target.

Useful7/10
Difficulty3/10
Novelty7/10
Paper: Exact Limits of Random Projections for Preserving Geometry: Distance Recovery, Nearest-Neighbor Rankings, and Covariance Shape in Gaussian Models arXiv:2609.02155
✗ Failed on benchmark 2026

Centered-Geometry Projection Loss

Train a low-dimensional projection of embeddings against centered pairwise geometry instead of only using raw-distance preservation or a JL-style guarantee. The loss removes the population or minibatch distance baseline before comparing distances, forcing the bottleneck to retain the fluctuations that carry ranking and task information.

Useful7/10
Difficulty4/10
Novelty6/10
Paper: Exact Limits of Random Projections for Preserving Geometry: Distance Recovery, Nearest-Neighbor Rankings, and Covariance Shape in Gaussian Models arXiv:2609.02155
△ Mechanism confirmed, baseline not beaten 2026

Co-Prime Virtual-Aperture Attention

Replace dense or single-dilation sparse attention with two sequential sparse attention stages whose offsets form co-prime arithmetic progressions. The first stage mixes tokens separated by multiples of M2, the second by multiples of M1; their composition reaches virtual offsets mM2+nM1, providing many structured long-range interactions from only M1+M2-1 physical offset families. Use causal masking and residual connections so the module can replace a standard transformer attention block without…

Useful7/10
Difficulty5/10
Novelty7/10
Paper: ISAC with Co-Prime Arrays: Virtual-Aperture Sensing and uplink downlink communications arXiv:2609.01979
✗ Failed on benchmark 2026

Spectral quadrature features

Replace random Fourier or random NTK features by a weighted deterministic quadrature rule for the kernel's feature integral. The resulting feature map uses the same linear-model interface as random features but can approximate the leading Gram-matrix eigenvalues substantially better at the same feature count, improving conditioning and reducing the width required for a target kernel approximation.

Useful7/10
Difficulty4/10
Novelty5/10
Paper: Spectral Bounds for Kernel Quadrature arXiv:2609.00553
△ Mechanism confirmed, baseline not beaten 2026

Block-TT 3D Neural Operator

Represent a large linear map acting on a Cartesian 3D grid and multiple physical channels as a TT-matrix, while retaining separate TT blocks for channel couplings that have different semantics. Apply the layer by sequential contractions with TT cores rather than materializing a dense matrix or a full 3D convolution kernel. Rank truncation provides an explicit accuracy-versus-memory knob and can be applied after optimizer updates.

Useful7/10
Difficulty5/10
Novelty5/10
Paper: Tensor-Train Methods for 3D Linear Elasticity: Block and Global Operator Representations with Solver Performance Analysis arXiv:2608.23595