ToElementMesh::femtemnbb

Details

This message is generated when no numeric bounds can be computed for a region.
This error can be avoided by specifying explicit numerical bounds.
Off[message] switches off the message; On[message] switches it on. For example: Off[ToElementMesh::femtemnbb].

For an infinite region, no region bounds can be computed:

Wolfram Language code: Needs["NDSolve`FEM`"]

Wolfram Language code: ToElementMesh[ImplicitRegion[x > y, {x, y}]]

Default values for the bounding box will be used. The issue is best addressed by specifying explicit numerical bounds:

Wolfram Language code: mesh = ToElementMesh[ImplicitRegion[x > y, {x, y}], {{-2, -1}, {-2, -1}}]

Inspect the bounds:

Wolfram Language code: mesh["Bounds"]

This message can be generated by other functions:

Wolfram Language code: NIntegrate[1, {x, y}∈ImplicitRegion[x > y, {x, y}], Method -> "FiniteElement"]

The result is based on a region with the default bounds. Specifying region bounds addresses the issue:

Wolfram Language code: NIntegrate[1, {x, y}∈ImplicitRegion[x > y, {{x, -2, -1}, {y, -2, -1}}], Method -> "FiniteElement"]

If the region's bounds cannot be computed, system default values specified through the "DefaultBounds" option will be used:

Wolfram Language code: default = SystemOptions["FiniteElementOptions"]

The default values can be modified with a system option:

Wolfram Language code: SetSystemOptions["FiniteElementOptions" -> {"DefaultBounds" -> {-2, -1}}]

Wolfram Language code: mesh = ToElementMesh[ImplicitRegion[x > y, {x, y}]]

Inspect the bounds:

Wolfram Language code: mesh["Bounds"]

Restore the original default values:

Wolfram Language code: SetSystemOptions[default]

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