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© 2026 Dystr · Made withfor the scientific community.

RunMat™ is a registered trademark of Dystr, Inc. MATLAB® is a registered trademark of The MathWorks, Inc. RunMat is not affiliated with, endorsed by, or sponsored by The MathWorks, Inc.

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Builtin Reference
    • fea.boundaryCondition
    • fea.compare
    • fea.domain
    • fea.field
    • fea.interface
    • fea.loadCase
    • fea.material
    • fea.materialAssignment
    • fea.model
    • fea.plan
    • fea.plot
    • fea.results
    • fea.run
    • fea.runOptions
    • fea.step
    • fea.study
    • fea.sweep
    • fea.trends
    • fea.validate

fea.materialAssignment — Assign a RunMat FEA material to a region.

fea.materialAssignment(region, material, Name, Value, ...) creates an exact region-to-material assignment with optional expected-material and evidence-confidence metadata.

Syntax

assignment = fea.materialAssignment(region, material, Name, Value, ...)

Inputs

NameTypeRequiredDefaultDescription
regionStringScalarYes—Geometry region selector.
materialStringScalarYes—Assigned material id.
Name, ValueAnyVariadic—Expected-material and confidence options.

Returns

NameTypeDescription
resultAnyFEA object or operation result.

Errors

IdentifierWhenMessage
RunMat:fea:LoadFailedA .fea document cannot be read, parsed, or resolved.fea: failed to load FEA document
RunMat:fea:InvalidInputA builtin receives an unsupported argument pattern or object type.fea: invalid input
RunMat:fea:OperationFailedA validation, planning, run, result-query, comparison, or trend operation fails.fea: operation failed
RunMat:fea:InternalAn FEA object or operation result cannot be converted to a RunMat value.fea: internal error

How fea.materialAssignment works

  • Region, assigned material, and optional expected material are exact text identifiers.
  • Confidence is an enumerated structural value and defaults to verified.
  • No numeric field exists; integer and resident numeric inputs are rejected before assignment construction.
  • Region existence and material consistency are checked when the assignment is assembled into or validated with a model.

Example

Assign steel to a region

assignment = fea.materialAssignment("name:Bracket", "steel");

Using fea.materialAssignment with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how fea.materialAssignment changes the result.

Run a small fea.materialAssignment example, explain the result, then change one input and compare the output.

FAQ

Does construction prove the region exists?⌄

No. Construction preserves the selector; model assembly and validation resolve it against geometry.

Related Fea functions

fea.boundaryCondition · fea.compare · fea.domain · fea.field · fea.interface · fea.loadCase · fea.material · fea.model · fea.plan · fea.plot · fea.results · fea.run · fea.runOptions · fea.step · fea.study · fea.sweep · fea.trends · fea.validate

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how fea.materialAssignment is executed, line by line, in Rust.

  • View the source for fea.materialAssignment in Rust on GitHub
  • Learn how the RunMat runtime works
  • Found a bug? Open an issue with a minimal reproduction.

About RunMat

RunMat is an open-source runtime that executes MATLAB-syntax code blazing on any GPU. It is licensed under the Apache 2.0 license.

  • RunMat automatically optimizes your math for GPU execution on Apple, Nvidia, and AMD hardware. No code changes needed. Simulations that took hours now take minutes.
  • Start running code in seconds. RunMat runs in the browser, on the desktop, or from the CLI. No license server, no IT ticket.

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On this page
  • Syntax
  • Inputs
  • Returns
  • Errors
  • How fea.materialAssignment works
  • Example
  • Assign steel to a region
  • Using fea.materialAssignment with coding agents
  • FAQ
  • Related Fea functions
  • Open-source implementation
  • About RunMat