GradSkip and GradSkip+ Communication-Accelerated Local Gradient Methods with Gradient Skipping
Algorithms AIMech:GradSkipAndGradSkipPlusCommunicationAcceleratedLocalGradientMethodsWithGradientSkipping DRAFT
Aliases: GradSkip, GradSkip+, GradSkip Local Gradient Skipping Algorithm, Communication-Accelerated Local Gradient Method with Gradient Skipping
A family of communication-accelerated distributed local gradient methods (GradSkip in Algorithm 2 and its generalized compression-operator formulation GradSkip+ in Algorithm 3) that augment ProxSkip/Scaffnew's randomized consensus-skipping probability p with client-specific local gradient skipping probabilities q_i in (0, 1], whereby client i skips computing its true local gradient nabla f_i(x_i^t) with probability 1 - q_i (substituting its local shift control variate h_i^t for a fake local step hat{x}_i^{t+1} = x_i^t) and reduces expected per-client local gradient evaluations per communication round from 1/p to min{1/p, 1/(1 - q_i)} without degrading the accelerated O(sqrt(kappa_max) log(1/eps)) communication complexity.
Identity Notes & Concept Scope
Distinct from ProxSkip / Scaffnew (Mishchenko et al., ICML 2022; which sets q_i = 1 for all clients and forces every client to compute 1/p local gradients per communication round regardless of local condition number kappa_i = L_i / mu). GradSkip and GradSkip+ (Maranjyan, Safaryan, & Richtarik, arXiv:2210.16402) decouple local gradient computation frequency q_i from communication frequency p.
Claims & Grounded Evidence
4 Claims
Mechanism
#gradskip-coupled-bernoulli-communication-and-local-gradient-skipping-mechanism
In GradSkip (Algorithm 2), at each iteration t the server flips a global coin theta_t ~ Bernoulli(p); when theta_t = 1 (communication round), every client i sets lambda_i^t = 1, evaluates nabla f_i(x_i^t), takes step hat{x}_i^{t+1} = x_i^t - gamma (nabla f_i(x_i^t) - h_i^t), averages x_i^{t+1} = (1/n) sum_j (hat{x}_j^{t+1} - (gamma/p) h_j^t), and updates its control variate h_i^{t+1} = h_i^t + (p/gamma)(x_i^{t+1} - hat{x}_i^{t+1}); when theta_t = 0 (local round), each client independently flips eta_i^t ~ Bernoulli(q_i) and skips computing nabla f_i(x_i^t) whenever eta_i^t = 0 by substituting tilde{g}_i^t = h_i^t so hat{x}_i^{t+1} = x_i^t.
Scope
#gradskip-heterogeneous-condition-number-computational-reduction-scope
For L_i-smooth mu-strongly convex local objectives with condition numbers kappa_i = L_i / mu and kappa_max = max_i kappa_i (Theorem 4.3 & Section 4.3 Equations 11-13), choosing gamma = 1 / L_max, p = 1 / sqrt(kappa_max), and q_i = (1 - 1/kappa_max)(kappa_i / kappa_max) contracts the Lyapunov function Psi^t at rate (1 - 1/kappa_max), preserving Scaffnew's accelerated O(sqrt(kappa_max) log(1/eps)) communication rounds while reducing client i's expected local gradient computations per communication round to E[tau_i] = (1 - p(1 - q_i)) / (p + q_i - p q_i) <= min{1/p, 1/(1 - q_i)} (Lemma B.1).
Limitation
#gradskip-strong-convexity-and-synchronized-communication-trigger-limitation
The linear convergence rate O(sqrt(kappa_max) log(1/eps)) and condition-number-matched skipping schedule q_i require mu-strong convexity (Assumption 3.2) and a shared global Bernoulli communication coin theta_t ~ Bernoulli(p) across participating clients.
Application
#gradskip-heterogeneous-federated-optimization-with-unequal-client-compute-application
Applied to federated regularized logistic regression across clients with heterogeneous data smoothness constants L_i and unequal local computational speeds.
⚠️ Curated Limitations & Negative Results
- Requires mu-strong convexity for the accelerated linear convergence rate and condition-number-matched local gradient skipping probabilities.
- Relies on a shared global Bernoulli communication coin across participating clients.
Artificial Intelligence Ontology (AIO) Grounding
Mapped AIO Classes
| AIO Target Class | Mapping Relation | Mapping Rationale |
|---|---|---|
AIO:FederatedLearning
Federated Learning
|
related_match | GradSkip and GradSkip+ are communication-accelerated federated local gradient methods with client-adaptive local gradient skipping. |
Evidence Sources & Primary Literature
3 Sources| Source ID | Publication / Document | Type / Access | Reference & Checksum |
|---|---|---|---|
r562-primary-pdf
|
Artavazd Maranjyan, Mher Safaryan, Peter Richtarik
|
primary paper
full_text
|
ID: https://api.openalex.org/works/https://doi.org/10.48550/arXiv.2210.16402
sha256:561cb129942c…
|
r562-arxiv-abs
|
Artavazd Maranjyan, Mher Safaryan, Peter Richtarik
|
primary paper
abstract_only
|
ID: https://arxiv.org/abs/2210.16402
sha256:bcc259afcad4…
|
r562-metadata-cr
|
Artavazd Maranjyan, Mher Safaryan, Peter Richtarik
|
primary paper
abstract_only
|
ID: https://api.openalex.org/works/https://doi.org/10.48550/arXiv.2210.16402
sha256:36b3eceb98a7…
|
Ontology & Grounding Topology
Open in interactive network graph →Curation Provenance
Curator: Antigravity
Method: ai_assisted
Model: Gemini
Created: 2026-10-19T10:45:00Z
Updated: 2026-10-19T10:45:00Z
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