I’m a total beginner at using FreeFEM++. I wanted to calculate the negative part of an fespace X by using

max(-X, 0.0);

but it didn’t work. Instead, I used a loop like this:

for(int i = 0; i < Vh.ndof; ++i) {
X[i] = max(-X[i], 0.0);
}

which worked. I understand that max doesn’t apply to fespaces. But some operations do apply. I tried searching the documentation but I couldn’t find a list of what are valid operations. Can anyone help?