Hi,

I brand new to Freefem and I don’t manage to code this variational problem :

Where Q=(0,1)^2 and (e_1,e_2) is the canonical basis of R^2. I have an error while integrating w_i over Q. Here is my code :

int k=8;

int s=2^(k);

mesh Th = square(s, s);

//The finite element space defined over Th is called here Vh

fespace Vh(Th, P1, periodic=[[2, y], [4, y], [1, x], [3, x]]);

Vh u, v;// Define u and v as piecewise-P1 continuous functions

// Define f

func f= 1 + 100cos(x)^2sin(y)^2;

// Define and solve the PDE

solve nohomo(u, v)

= int2d(Th)( f*(dx(u)*dx(v) + dy(u)*dy(v)) )

+ int2d(Th)(u) * int2d(Th)(v)

+ int2d(Th)(f * dx(v)) ;

plot(u);

In the code reduced the formula (11) of the picture, you don’t need to worry about that, since my issue is that i can’t use “int2d(Th)(u)”.

And here is the error :

21 : + int2d(Th)(u) error operator <20CDomainOfIntegration>, <10LinearCombI7MGauche4C_F0E>

List of choices

( <12FormBilinear> : <20CDomainOfIntegration>, <10LinearCombISt4pairI7MGauche6MDroitE4C_F0E> )

( : <20CDomainOfIntegration>, )

( : <20CDomainOfIntegration>, )

( <10FormLinear> : <20CDomainOfIntegration>, <10LinearCombI6MDroit4C_F0E> )

Error line number 21, in file C:\Users\theop\Desktop\test.edp, before token )

What is wrong ?

Thanks !