Update build_circular_coil.m

fw = dz/nturns;

fh = (r2-r1)/nlayers;

zwind0 = repmat([z1+fw/2:fw:z1+dz-fw/2],1,nlayers);

rwind0 = repmat([r1+fh/2:fh:r2-fh/2],1,nturns);

fw = dz/nturns; % Width (axial length) of each turn

fh = (r2-r1)/nlayers; % Thickness (radial length) of each layer

% r,z positions of the center of each filament

zwind0 = repmat(linspace(z1+fw/2,z1+dz-fw/2,nturns),1,nlayers);

rwind0 = repmat(linspace(r1+fh/2,r2-fh/2,nlayers),1,nturns);

thetas = linspace(0,2*pi,ntheta_per_wind);