# GlobalFunction¶

class GlobalFunction(*args)

GetFEM GlobalFunction object

Global function object is represented by three functions:

• The function val.
• The function Hessian hess.

this type of function is used as local and global enrichment function. The global function Hessian is an optional parameter (only for fourth order derivative problems).

General constructor for GlobalFunction objects

• GF = GlobalFunction('cutoff', int fn, scalar r, scalar r1, scalar r0) Create a cutoff global function.
• GF = GlobalFunction('crack', int fn) Create a near-tip asymptotic global function for modelling cracks.
• GF = GlobalFunction('parser', string val[, string grad[, string hess]]) Create a global function from strings val, grad and hess. This function could be improved by using the derivation of the generic assembly language … to be done.
• GF = GlobalFunction('product', GlobalFunction F, GlobalFunction G) Create a product of two global functions.
• GF = GlobalFunction('add', GlobalFunction gf1, GlobalFunction gf2) Create a add of two global functions.
char()

Output a (unique) string representation of the GlobalFunction.

This can be used to perform comparisons between two different GlobalFunction objects. This function is to be completed.

display()

displays a short summary for a GlobalFunction object.

grad(PTs)

Return grad function evaluation in PTs (column points).

On return, each column of GRADs is of the form [Gx,Gy].

hess(PTs)

Return hess function evaluation in PTs (column points).

On return, each column of HESSs is of the form [Hxx,Hxy,Hyx,Hyy].

val(PTs)

Return val function evaluation in PTs (column points).