# [Getdp] distance dependent constraint

JORGE MIAJA HERNANDEZ j.miaja at alumnos.upm.es
Mon Feb 4 11:56:59 CET 2019

```Hello everybody,

(in 2D)
I want to test the vector potential dynamic formulation for
superconducting materials
and have set up an example in which a superconducting block is placed in
a constant
magnetic field.

To create this constant magnetic field, I need to force the magnetic
vector potential
to be "x" on the boundary, so the constraint on each point along the
boundary (the circle
that encloses my example) depends on the x distance of that point to
the centre.

The issue I am having... I get this error:
"GetDP - Function 'boundaryA' undefined in Region 110"
Which I do not understand... since boundaryA and the constraint I have
defined do not have
anything to do with Region 110

This is the part of the code interesting to the case

Group{
Air = Region[ 110 ];
block = Region[ 111 ];
contour = Region[ 100 ];

Vol_tot = Region[ {block, Air} ];
Vol_block = Region [ block ];
Sur_contour = Region[ contour ];
}

Function{
mu0 = 4.e-7 * Pi;
nu [ Region[{Air, block}] ]  = 1. / mu0;
boundaryA[ contour ] = X[];
// I have tried writing  boundaryA[ Region{contour, Air} ] = X[];
// but I get a syntax error on that line
}

Constraint{
{ Name vectorPotA_contour;
Case {
{ Region Sur_contour; Value boundaryA[]; }
}
}
}

FunctionSpace{
{ Name VecPotA; Type Form1P;
BasisFunction{ { // a(x,y) = sum_k aCoef_k sBF_k(x,y)
Name sBF; NameOfCoef aCoef; Function BF_PerpendicularEdge;
Support Dom_VecPotA; Entity NodesOf[All];
} }
Constraint{ { NameOfCoef aCoef; EntityType NodesOf;
NameOfConstraint vectorPotA_contour; } }
}
}

--
JORGE MIAJA HERNANDEZ