Rejection-Free Parallel MCMC Sampling for Accurate State-Space Estimation

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Solution Overview

Problem

Existing sampling techniques, such as Digital Annealers, require significant computing resources and can distort the distribution of state spaces, leading to incorrect representations, while traditional MCMC processes may perform invalid operations.

Innovation Solution

A Digital Sampler utilizing a rejection-free MCMC process calculates multiplicities for each trial, allowing for parallel swapping of replicas at different temperatures to efficiently sample state spaces, reducing computational overhead and preserving information about local extrema.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Digital Annealers are used as samplers, then sampling can be performed, but significant computing resources are required and the distribution of state spaces may be distorted

Engineering Contradiction:
Improvesampling capabilityVSAvoidcomputing resources
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system segments the sampling process into multiple independent MCMC chains running in parallel, each handling a portion of the state space exploration. This division allows for more efficient resource utilization compared to a single centralized Digital Annealer approach.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the operational parameters by using rejection-free MCMC processes with carefully controlled temperature schedules and multiplicity factors, allowing efficient sampling without the resource-intensive operations of traditional Digital Annealers.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If traditional Digital Annealer operations are performed, then sampling operations can be executed, but the Markov Chain Monte Carlo process may become invalid

Engineering Contradiction:
Improvesampling operation executionVSAvoidMarkov Chain Monte Carlo process validity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements feedback mechanisms where multiplicity calculations inform the sampling process, ensuring that the MCMC operations maintain validity while achieving efficient sampling. The feedback loop adjusts operations based on observed state space characteristics.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention replaces the mechanical Digital Annealer operation sequence with a software-based rejection-free MCMC process that uses random bit flipping and multiplicity calculations, achieving valid Markov Chain sampling without the invalid operations inherent in traditional Digital Annealer approaches.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If MCMC trials are performed with rejection operations, then sampling can be performed, but repetition increases processing time

Engineering Contradiction:
Improvesampling capabilityVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The invention extracts and eliminates the rejection operation from the MCMC process entirely. By using rejection-free sampling with multiplicity-weighted state transitions, the system removes the time-wasting repetition inherent in traditional MCMC methods that accept and reject proposals.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs preliminary multiplicity calculations that determine the effective weight of each state before sampling occurs. This preliminary action ensures that subsequent sampling operations are efficient and do not require rejection-based corrections, reducing processing time.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20250217682A1Statistical sampling using rejection-free parallel trial markov chain monte carlo processes
Publication Date: 2025.07.03 FUJITSU LTD
  • US20250217682A1 patent drawing
  • US20250217682A1 patent drawing
  • US20250217682A1 patent drawing

AI summary

A method may include obtaining replicas that represent estimated states of a system. A first replica having the lowest temperature in a first set of temperatures may be identified and written to a first state of a memory. The method may include performing a first Markov Chain Monte Carlo (MCMC) trial on each replica to simulate the effects of a change in the temperature of the respective replica. A second replica having the lowest temperature in a second set of temperatures may be identified and written to a second state of the memory. A first and second multiplicity of the first and second replicas may be calculated, the multiplicities representing estimations of the quantities of MCMC trials which would result in rejection. A representation of an end state of the system may be generated based on the first replica, the second replica, the first multiplicity, and the second multiplicity.