pyLibMeshb

Python module to read/write mesh and solution files in Gamma Mesh Format (.mesh/.meshb/.sol/.solb). Implemented by compiling the vendored libMeshb source (libmeshb8.c / libmeshb8.h) directly and binding via Python ctypes.

PyPI distributions include precompiled shared libraries for Linux, Windows, and macOS, so most users can install with pip install pyLibMeshb without a C compiler or build toolchain. Wheels bundle the compiled libmeshb8 binary with the Python ctypes bindings, so the extension loads correctly on the host platform. If no prebuilt wheel matches your platform, pip falls back to building from source.

Getting Started

Install

pip install pyLibMeshb

Read and write mesh data

Import pyLibMeshb

import pyLibMeshb.libMeshb as lm

Check mesh information.

lm.mesh_info("naca0012.meshb")

 File          : naca0012.meshb
 Version       : 2
 Dimension     : 2
 Type                     Kind             Count   Details
 ----------------------------------------------------------------------
 vertices                 vertex            4796
 edges                    element            192
 triangles                element           9400

Read a mesh.

mesh = lm.read("naca0012.meshb")

Mesh data is stored in a dictionary with keys for each data type.

print(mesh.keys())

dict_keys(['version', 'dim', 'vertices', 'edges', 'triangles'])

Write the mesh back out.

lm.write("roundtrip.meshb", mesh)

Verify consistency.

import numpy as np
check = lm.read("roundtrip.meshb", types=["vertices"])
print("Round-trip vertices match:", np.allclose(mesh["vertices"], check["vertices"]))

Round-trip vertices match: True

Read and write solution data

Solution demo: 3 synthetic scalar fields (e.g. density, pressure, Mach).

n = mesh["vertices"].shape[0]
demo_values = np.column_stack([
    np.linspace(1.0, 2.0, n),
    np.linspace(101325.0, 90000.0, n),
    np.linspace(0.1, 3.5, n),
])
lm.write("naca0012.solb", {"version": 3, "dim": 2, "sol_at_vertices": {"values": demo_values}})

Check solution file information.

lm.mesh_info("naca0012.solb")

File          : naca0012.solb
Version       : 3
Dimension     : 2
Type                     Kind             Count   Details
----------------------------------------------------------------------
sol_at_vertices          solution          4796   sol_size=3, field_types=[1, 1, 1]

Solution data can be read using lm.read(). The mesh and solution can be visualized with Vizir4.

Query data types

Get lists of types in this mesh file.

mesh_types = lm.list_types("naca0012.meshb")
print(mesh_types)

['edges', 'triangles', 'vertices']

Get lists of types in this solution file.

solution_types =  lm.list_types("naca0012.solb")
print(solution_types)

['sol_at_vertices']

Get list of all types supported by pyLibMeshb.

all_types = lm.list_types()
print(all_types)

['corners', 'dsol_at_vertices', 'edges', 'hexahedra', 'isol_at_edges', 'isol_at_hexahedra', 'isol_at_prisms', 'isol_at_pyramids', 'isol_at_quadrilaterals', 'isol_at_tetrahedra', 'isol_at_triangles', 'isol_at_vertices', 'prisms', 'pyramids', 'quadrilaterals', 'ridges', 'sol_at_edges', 'sol_at_hexahedra', 'sol_at_prisms', 'sol_at_pyramids', 'sol_at_quadrilaterals', 'sol_at_tetrahedra', 'sol_at_triangles', 'sol_at_vertices', 'tetrahedra', 'triangles', 'vertices']

Testing

Install the package with its test dependencies and run the automated tests:

python -m pip install -e ".[test]"
python -m pytest

Credits

• LibMeshb — Loïc Maréchal, INRIA
• LibMeshb license — /csrc/libMeshb/LICENSE.txt