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Version: 0.3.1

FEAScriptWorker

FEAScriptWorker runs a FEAScriptModel in a web worker, so a long simulation does not block the page. It has the same configuration methods as FEAScriptModel, but every method is asynchronous and returns a Promise.

note

FEAScriptWorker is available in the browser only. It loads feascript-worker.esm.js from the same folder as feascript.esm.js, so keep the two files together when you host the library yourself.

import { FEAScriptWorker, plotSolution } from "https://core.feascript.com/dist/feascript.esm.js";

// 1. Create the model in a web worker and select the physics
const model = new FEAScriptWorker();
await model.ping(); // Wait until the worker is ready
await model.setModelConfig("frontPropagationScript");

// 2. Define the mesh
await model.setMeshConfig({
  meshDimension: "2D",
  elementOrder: "quadratic",
  numElementsX: 12,
  numElementsY: 8,
  maxX: 4,
  maxY: 2,
});

// 3. Apply the boundary conditions
await model.addBoundaryCondition("0", ["constantValue", 0]); // Bottom: initial front
await model.addBoundaryCondition("1", ["constantValue", 0]); // Left: initial front
await model.addBoundaryCondition("2", ["zeroGradient"]); // Top
await model.addBoundaryCondition("3", ["constantValue", 0]); // Right: initial front

// 4. Solve
await model.setSolverMethod("lusolve");
const result = await model.solve();

// 5. Plot the results in the main thread
const modelInfo = await model.getModelInfo();
plotSolution(modelInfo, result, "contour", "resultsCanvas");

// 6. Terminate the worker
model.terminate();

Methods​

MethodReturnsDescription
setModelConfig(modelConfig, options)Promise<boolean>Selects the model and its options, as FEAScriptModel
setMeshConfig(meshConfig)Promise<boolean>Sets the mesh, as FEAScriptModel.setMeshConfig
addBoundaryCondition(boundaryKey, condition)Promise<boolean>Adds a boundary condition
setSolverMethod(solverMethod)Promise<boolean>Selects the solver method
solve(options)Promise<object>Solves the model in the worker (maxIterations, tolerance)
getModelInfo()Promise<object>{ solverConfig, meshConfig, boundaryConditions, solverMethod }
ping()Promise<boolean>Resolves to true when the worker is ready
terminate()–Stops the worker

solve() resolves to { solutionVector, nodesCoordinates, solverConfig, meshDimension }, plus fields for the creeping flow and Euler–Bernoulli beam models (see Visualization). The object returned by getModelInfo() can be passed as the model argument of the plotting functions.

Model options​

setModelConfig and solve take the same options as in FEAScriptModel, including coefficientFunctions, nonlinear, maxIterations and tolerance:

await model.setModelConfig("generalFormPDEScript", {
  coefficientFunctions: {
    A: (x) => 1, // Diffusion coefficient
    B: (x) => -10, // Advection coefficient
    C: (x) => 0, // Reaction coefficient
    D: (x) => 10 * Math.exp(-200 * Math.pow(x - 0.5, 2)), // Source term
  },
});

Functions cannot be sent to a web worker, so FEAScriptWorker sends each coefficient function as its source code and rebuilds it in the worker. A rebuilt function does not have access to the variables around it, so write the values into the function:

const Da = 0.5;

// Does not work in the worker: Da is not defined there
D: (x, u) => Da * u ** 2,

// Works in the worker
D: (x, u) => 0.5 * u ** 2,

Use functions defined in your own code: built-in functions such as Math.sin must be wrapped, e.g. (x) => Math.sin(x). Rebuilding the functions requires eval, so a page with a Content Security Policy must allow 'unsafe-eval'.

Limitations​

  • solveAsync and the "jacobi-gpu" method are not available through the worker.

Examples​