For contour, create a matrix for ‘v’ and ‘n’ using either ndgrid or meshgrid, then specify [0 0] as the contour to plot:
NM = number_of_elements;
vv = linspace(minvalv, maxvalv, N);
nv = linspace(minvaln, maxvaln, N);
[Vm,Nm] = ndgrid(vv, nv);
Fm = F(vv,nv,,i,a,b,vNa,vK,vL);
figure
C = contour(Vm,Nm,Fm, [0 0])
That will plot them. To retrieve the (x,y) values, use find to determine the locations of ‘C(1,:)’ that equal zero, then ‘C(2,:)’ of those indices are the number of (x,y) pairs in the contour. That will determine how to recover them.
It will likely be easier to plot and recover the data from the fimplicit plot.
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