# GeoTrans¶

class GeoTrans(*args)

GetFEM GeoTrans object

The geometric transformation must be used when you are building a custom mesh convex by convex (see the add_convex() function of Mesh): it also defines the kind of convex (triangle, hexahedron, prism, etc..)

General constructor for GeoTrans objects

• GT = GeoTrans(string name) The name argument contains the specification of the geometric transformation as a string, which may be:

• GT_PK(n,k) : Transformation on simplexes, dim n, degree k.
• GT_QK(n,k) : Transformation on parallelepipeds, dim n, degree k.
• GT_PRISM(n,k) : Transformation on prisms, dim n, degree k.
• GT_PRODUCT(A,B) : Tensorial product of two transformations.
• GT_LINEAR_PRODUCT(GeoTrans gt1,GeoTrans gt2) : Linear tensorial product of two transformations
char()

Output a (unique) string representation of the GeoTrans.

This can be used to perform comparisons between two different GeoTrans objects.

dim()

Get the dimension of the GeoTrans.

This is the dimension of the source space, i.e. the dimension of the reference convex.

display()

displays a short summary for a GeoTrans object.

is_linear()

Return 0 if the GeoTrans is not linear.

nbpts()

Return the number of points of the GeoTrans.

normals()

Get the normals for each face of the reference convex of the GeoTrans.

The normals are stored in the columns of the output matrix.

pts()

Return the reference convex points of the GeoTrans.

The points are stored in the columns of the output matrix.

transform(G, Pr)

Apply the GeoTrans to a set of points.

G is the set of vertices of the real convex, Pr is the set of points (in the reference convex) that are to be transformed. The corresponding set of points in the real convex is returned.