Phrogz / simulated-annealing

Simulated Annealing optimization algorithm for node.js

Simulated Annealing for node.js

Simulated Annealing optimization algorithm for node.js.

Install

npm install --save simulated-annealing

Usage

var simulatedAnnealing = require('simulated-annealing');
var result = simulatedAnnealing(params);

Params

• initialState — first state value
• tempMax — initial temperature
• tempMin — min temperature when algorithm will stop
• newState — function for generating new state from current state newState(state)
• getTemp — function for generating new temperature based on previous temperature getTemp(temperature)
• getEnergy — function for calculating energy for state getEnergy(state) (less is better)
• clone — (optional) function to be called each time a copy of the state needs to be recorded; will be invoked with the state as both the this context, and also passed as a parameter
• occasionallyInvoke — (optional) function to invoke during simulation; will be passed six parameters:
  • the current state
  • the energy of the current state
  • the best state so far
  • the energy of the best state
  • the current temperature
  • the number of iterations
• invokeEvery — (optional) how often to invoke the occasionallyInvoke function. For example, a value of 100 will invoke the function every 100 iterations.

Example

Find solution for x^2=16

var simulatedAnnealing = require('simulated-annealing');

function getEnergy(v) {
    return Math.abs(v * v - 16);
}

function newState(x) {
    return x + (Math.random() - 0.5);
}

// linear temperature decreasing
function getTemp(prevTemperature) {
    return prevTemperature - 0.001;
}

var result = simulatedAnnealing({
    initialState: Math.random() * 16,
    tempMax: 15,
    tempMin: 0.001,
    newState: newState,
    getTemp: getTemp,
    getEnergy: getEnergy,
});

Testing

npm test