mkgeo_ball(1) build an unstructured mesh of an ellipsoid, in 2d or 3d

## SYNOPSIS

mkgeo_ball options [n]

## EXAMPLE

The following command build a triangle based 2d unstructured mesh of the unit ball

```        mkgeo_ball -t 10 > ball-10.geo
geo -mayavi ball-10.geo

```
or in one comand line:

```        mkgeo_ball -t 10 | geo -mayavi -

```

## DESCRIPTION

This command is usefull when testing programs on simple geometries. Invocation is similar to mkgeo_grid (see mkgeo_grid(1), mkgeo_ugrid(1)). It calls gmsh as unstructured mesh generator. It avoid the preparation of an input file for a mesh generator. The optional n argument is an integer that specifies the subdivision in each direction. By default n=10. The mesh files goes on standard output.

## ELEMENT TYPE OPTIONS

-t
2d mesh using triangles.
-q
2d mesh using quadrangles.
-tq
2d mesh using both triangles and quadrangles.

## THE MESH ORDER

-order int
The polynomial pproximation mesh order, for the curved boundary, as defined by gmsh. Defualt is order=1.

## THE GEOMETRY

The geometry can be ellipse/ellipsoid inscribted in the [a,b]x[c,d] rectangle or the [a,b]x[c,d]x[f,g] parallelotope. By default a=c=f=-1 and b=d=g=1, thus, the unit balls are considered.

-s
Only a surface mesh is generated: a curved line in 2d or a curved surface mesh in 3d. In 3d, supports both '-t' and '-q' options.
-a float
-b float
-c float
-d float
-f float
-g float

## BOUNDARY DOMAINS

The meshes defines a domain named boundary that groups all boundary sides.

## OTHERS OPTIONS

-fix
-nofix
By default, internal face and volume node from gmsh are recomputed, since they have incorrect coordinate that destroy the convergence properties of isoparametric high order elements (order >= 3). The -nofix option skip this correction: this option is available for test purpose.
-clean
clear temporary files (this is the default).
-noclean
does not clear temporary files.
-verbose
-noverbose
print intermediate commands and information messages.