FEAScriptModel

FEAScriptModel is the main class of FEAScript. It holds the configuration of a simulation (model, mesh, boundary conditions and solver) and solves it.

import * as math from "mathjs";
global.math = math;

import { FEAScriptModel } from "feascript";

const model = new FEAScriptModel();
model.setModelConfig("heatConductionScript");
model.setMeshConfig({ meshDimension: "1D", elementOrder: "linear", numElementsX: 10, maxX: 0.15 });
model.addBoundaryCondition("0", ["convection", 1, 25]);
model.addBoundaryCondition("1", ["constantTemp", 5]);
model.setSolverMethod("lusolve");
const { solutionVector, nodesCoordinates } = model.solve();

Constructor

new FEAScriptModel()

Creates an empty model. The solver method defaults to "lusolve".

Methods

setModelConfig(modelConfig, options)

Selects the physical model and sets its options.

Parameter	Type	Description
modelConfig	string	Name of the model (see below)
options	object	Optional model options (see below)

modelConfig	Model	Dimensions
"heatConductionScript"	Heat conduction	1D, 2D
"generalFormPDEScript"	General form PDE	1D
"frontPropagationScript"	Front propagation	2D
"creepingFlowScript"	Creeping flow	2D

Option	Type	Used by	Description
coefficientFunctions	object	General form PDE	Coefficients of the equation; see the model page
maxIterations	number	All	Maximum iterations of the iterative method in use
tolerance	number	All	Convergence tolerance of the iterative method in use

maxIterations and tolerance apply to the Jacobi solvers in linear models and to the Newton–Raphson method in the front propagation model; see Solvers for their defaults.

model.setModelConfig("generalFormPDEScript", {
  coefficientFunctions: {
    A: (x) => 1,
    B: (x) => -10,
    C: (x) => 0,
    D: (x) => 10 * Math.exp(-200 * Math.pow(x - 0.5, 2)),
  },
});

setSolverConfig(solverConfig, options)

Deprecated alias of setModelConfig, with the same parameters. It logs a deprecation warning; use setModelConfig. It was removed in version 0.3.0.

setMeshConfig(meshConfig)

Sets the mesh: either the parameters of a structured mesh or a mesh imported from Gmsh.

Property	Type	Description
meshDimension	string	"1D" or "2D" (required, also for parsedMesh)
elementOrder	string	"linear" (default) or "quadratic" (must match the elements of a parsedMesh)
numElementsX	number	Number of elements along $x$ (structured mesh)
numElementsY	number	Number of elements along $y$ (structured 2D mesh)
maxX	number	Length of the domain along $x$ (structured mesh)
maxY	number	Height of the domain along $y$ (structured 2D mesh)
angleLeft	number	Interior angle of the left side in degrees, default 90 (structured 2D mesh)
angleRight	number	Interior angle of the right side in degrees, default 90 (structured 2D mesh)
parsedMesh	object	Mesh returned by importGmshQuadTri

See Mesh for the geometry, the boundary keys and the node numbering.

addBoundaryCondition(boundaryKey, condition)

Adds a boundary condition, or replaces the condition of a boundary that already has one.

Parameter	Type	Description
boundaryKey	string	Boundary key ("0", "1", ...)
condition	array	Condition type followed by its parameters, e.g. ["convection", 1, 20]

See Boundary conditions for the condition types of each model. Condition types that the selected model does not recognize are ignored without a message.

setSolverMethod(solverMethod)

Selects the linear system solver: "lusolve" (default), "jacobi", "frontal" or "jacobi-gpu". See Solvers for the methods supported by each model.

solve(options)

Prepares the mesh, assembles the system, applies the boundary conditions and solves it. This method is synchronous.

Parameter	Type	Description
options	object	Optional { maxIterations, tolerance }; they take precedence over setModelConfig options

Returns an object with:

Property	Type	Description
solutionVector	number[]	The computed unknowns (see the model pages)
nodesCoordinates.nodesXCoordinates	number[]	$x$ coordinates of the mesh nodes
nodesCoordinates.nodesYCoordinates	number[]	$y$ coordinates of the mesh nodes (2D meshes)

For the heat conduction, general form PDE and front propagation models, solutionVector has one value per node, in the order of nodesCoordinates. For the creeping flow model, it holds the velocity components and the pressure in consecutive blocks.

solveAsync(computeEngine, options)

Asynchronous version of solve, used with the "jacobi-gpu" solver method. It returns a Promise that resolves to the same object as solve().

model.setSolverMethod("jacobi-gpu");
const { solutionVector, nodesCoordinates } = await model.solveAsync();

Parameter	Type	Description
computeEngine	object	Not used in version 0.2.0: FEAScript creates a WebGPU compute engine for every solve
options	object	Optional { maxIterations, tolerance }

caution

solveAsync supports only heatConductionScript with the "jacobi-gpu" solver method, in browsers with WebGPU support, with FEAScript imported from src/index.js (see Solvers). For other models or solver methods, it returns an empty solution vector.

Error handling

FEAScript reports configuration problems (for example a creeping flow model on linear elements, or a solver that did not converge) as [ERROR] messages in the console, and in most cases continues instead of throwing an exception. Some invalid configurations, such as a missing meshDimension, end in a JavaScript error later in the solution. Check the console output when a result looks wrong.