Description

Refine is a 3D mixed-element grid adaptation framework implemented in the C language.

Quick Start

If you checked out the repository with git, [requires automake >= 1.7 and autoconf >= 2.53]

 ./bootstrap
 mkdir -p build
 cd build
 ../configure --prefix=`pwd`
 make
 make install

See the INSTALL file for further build instructions. Here are some examples: with MPI and Zoltan,

../configure --with-zoltan=/zoltan/path CC=mpicc FC=mpif90 CFLAGS='-DHAVE_MPI'

with EGADS and OpenCASCADE,

../configure --with-EGADS=/egads/path --with-OpenCASCADE=/opencascade/path

with EGADSlite,

../configure --with-EGADS=/egads/path --enable-lite

These can be combined, e.g., MPI+Zoltan+EGADSlite.

Multiscale Metric for Control of Interpolation Error in Lp-norm

In conjunction with the Unstructured Grid Adaptation Working Group, an implementation of the multiscale metric is provided.

./build/src/ref_metric_test --lp project.meshb project-mach.solb 2 1.5 3.0e4 project-metric.solb [--kexact] [--hmax max_edge_length]

Where,

• project.meshb is the grid in libMeshb format
• project-mach.solb is a scalar field (Mach number) in libMeshb format
• 2 is the norm order
• 1.5 is the gradation limit
• 3.e4 is the complexity (C), where the new mesh will have approximately 2C vertices and 12C tetrahedra
• project-metric.solb is the output metric in libMeshb format
• use (sequential only) k-exact Hessian reconstruction with --kexact, otherwise default to L2-projection Hessian reconstruction
• max_edge_length is an optional limit on maximum edge length with an attempt to hold complexity

See LoicMarechal/libMeshb for details on the libMeshb format.

Metric Conformity Evaluation

In conjunction with the Unstructured Grid Adaptation Working Group, an implementation of descriptive statistics for edge lengths and mean ratio is provided.

./build/src/ref_histogram_test project.meshb project-metric.solb

Where,

• project.meshb is the grid in libMeshb format
• project-metric.solb is the metric in libMeshb format

See LoicMarechal/libMeshb for details on the libMeshb format. Histograms are written as ref_histogram_quality.tec and ref_histogram_ratio.tec, where each of the two the columns are mean ratio/edge length and normalized count.

Scalar Field for Interpolation Error Verification

To create an initial unit cube domain

./build/src/ref_acceptance 1 initial.meshb

To compute the scalar on a domain,

./build/src/ref_acceptance -u tanh3 project.meshb project-scalar.solb

Where,

• tanh3 can be sinfun3, sinatan3, or tanh3
• project.meshb is the grid in libMeshb format
• project-scalar.solb is a scalar field in libMeshb format

Interpolation Error Evaluation

The norm of interpolation error of a scalar function on a "candidate" grid can be computed based on a scalar function on "truth" grid. The candidate solution is interpolated to the truth grid, assuming the solution is linear in each element, and a norm of the difference of the interpolated candidate solution and the truth solution is integrated on the truth grid.

./build/src/ref_interp_test --error truth.meshb truth-scalar.solb candidate.meshb candidate-scalar.solb 2

Where,

• truth.meshb is the truth grid in libMeshb format
• truth-scalar.solb is truth scalar field in libMeshb format
• candidate.meshb is the candidate grid in libMeshb format
• candidate-scalar.solb is candidate scalar field in libMeshb format
• 2 is the power of the norm

The output is two numbers: the characteristic edge length (number of vertices raised to the -1/3 power) and the interpolation error norm.

Field Interpolation

The fields in a .solb file paired with a donor mesh can be interpolated to a receptor mesh. This utility can be executed in serial or parallel.

./build/src/ref_interp_test --field donor-mesh.ext donor-field.solb receptor-mesh.ext receptor-field.solb

Where,

• donor-mesh.meshb is the donor mesh in binary AFLR (.lb8.ugrid,.b8.ugrid) or libMeshb (.meshb) format
• donor-field.solb is the donor field(s) in libMeshb format
• receptor-mesh.ext is the receptor mesh in binary AFLR (.lb8.ugrid,.b8.ugrid) or libMeshb (.meshb) format
• receptor-field.solb is the receptor field(s) in libMeshb format

The output is receptor-field.solb.

Grid Adaptation

./build/src/ref_driver -i project.meshb -m project-metric.solb [-g project.egads] -x output.meshb

Where,

• -i project.meshb is the grid in libMeshb format
• -m project-metric.solb is the metric in libMeshb format
• -g project.egads is optional geometry (when compiled with EGADS)
• -x output.meshb is the output grid name