Frontend API Reference¶

This page summarizes the most commonly used frontend functions and fields. Detailed behavior is implemented in the language-specific frontend directories:

frontends/Matlab
frontends/Python/exasim
frontends/Julia/Exasim

Function Reference¶

Concept	MATLAB	Python	Julia	Purpose
Initialize app	`initializeexasim()`	`initializeexasim()`	`Exasim.initializeexasim()`	Return default `pde` and `mesh`.
Initialize PDE only	`initializepde(version)`	`initializepde(version)`	`Exasim.initializepde(version)`	Return default PDE configuration.
Preprocess	`preprocessing(pde, mesh)`	`preprocessing(pde, mesh)`	`Exasim.preprocessing(pde, mesh)`	Write backend input files and return updated `pde`, `mesh`, `master`, and `dmd`.
Run workflow	`exasim(pde, mesh)`	`exasim(pde, mesh)`	`Exasim.exasim(pde, mesh)`	Preprocess, generate, build, run, and fetch outputs.
Compile	`cmakecompile(pde)`	`cmakecompile(pde)`	`Exasim.cmakecompile(pde)`	Configure/build generated CMake app.
Run executable	`runcode(pde, numpde)`	`runcode(pde, numpde)`	`Exasim.runcode(pde, numpde)`	Launch solve or postprocess executable.
Export app	`exportapp(pde, dest)`	`exportapp(pde, dest)`	`Exasim.exportapp(pde, dest)`	Create standalone app bundle.
Visualize	`vis(visfields, app, mesh)`	`vis(visfields, app, mesh)`	`Exasim.vis(visfields, app, mesh)`	Write frontend visualization output.

Example:

from exasim import initializeexasim, exasim, exportapp

pde, mesh = initializeexasim()
pde["modelfile"] = "pdemodel"
sol, pde, mesh = exasim(pde, mesh)
exportapp(pde, "standalone_app")

Common `pde` Fields¶

Field	Default role	Notes
`model` / `pdemodel`	Model family name	MATLAB historically initializes `pdemodel`; Python/Julia expose `model`.
`modelfile`	Host-language model file	Omit extension in examples.
`physicsparam`	Single runtime physics vector	Passed to model callbacks as `param`.
`physicsparamsweep`	Optional matrix/list of physics vectors	Rows are cases.
`physicsparamwarmstart`	Optional sweep continuation flag	First case uses standard initialization; later cases reuse previous converged state.
`platform`	CPU/GPU selection	Must match installed backend support.
`mpiprocs`	Number of MPI ranks	Controls preprocessing and launch.
`datapath`	Runtime input/output root	Defaults to current directory.
`builddir` / `buildpath`	Generated build root	Defaults to `.exasim`.
`dataoutpath`	Optional output override	Used for sweep cases and custom output placement.
`executionmode`	Runtime mode	`0` solve, `1` postprocess.
`saveParaview`	Backend VTK output flag	Requires visualization field counts and callbacks.
`saveResNorm`	Residual-history output flag	Writes residual norm files.

Model Callback Names¶

Callbacks are generated only when the model and dimensions require them. Common names include:

initu, initq, initw, initodg
flux, source, tdfunc
ubou, fbou, fbouhdg, fhat, uhat, stab
visscalars, visvectors, vistensors
qoivolume, qoiboundary

See Model contract for semantics. See pdemodel abstraction for frontend-specific examples and data flow.

Language Differences¶

Topic	MATLAB	Python	Julia
Container	`struct`	`dict`	`PDEStruct`
Field access	`pde.field`	`pde["field"]`	`pde.field`
Package setup	`exasim_setup.m`	Python package/import path	`using Exasim`
Array convention	MATLAB column-major arrays	NumPy arrays; Exasim data follows backend layout	Julia column-major arrays
Export setting	`exportapp(pde, dest)`	`exportapp(pde, dest)`	`Exasim.exportapp(pde, dest)`

Text Frontend Compatibility¶

The pdeapp.txt workflow is not an interactive language frontend, but it uses the same core fields and the same backend runtime semantics. Use it when you want a compact, frontend-free input file for text2code-generated standalone applications.

physicsparam = 1.4 0.72 2000.0
saveParaview = 1

See pdeapp.txt fields and text2code.