Numerical method of the "fimplicit" function

Hello, does anyone know what kind of numerical methods are used in the "fimplicit" function? I cannot find any information about this. Thank you!

Answer 1

[Torsten]

Since you can specify a mesh density in x- and y- direction, my guess is that the function is simply evaluated on X x Y. Sign changes indicate the contour line for f(X,Y) = 0.