    gmin = -5;
    cmax = 5;
end
if nargin < 3
    msestep = 0.1;
    v = 3;
    cstep = 1;
    gstep = 1;
    gmax = 5;
    gmin = -5;
    cmax = 5;
    cmin = -5;
end
% X:c Y:g cg:mse
[X,Y] = meshgrid(cmin:cstep:cmax,gmin:gstep:gmax);
[m,n] = size(X);
cg = zeros(m,n);
% record accuracy with different c & g,and find the best mse with the smallest c
bestc = 0;
bestg = 0;
mse = 10^10;
basenum = 2;
for i = 1:m
    for j = 1:n
        cmd = ['-v ',num2str(v),' -c ',num2str( basenum^X(i,j) ),' -g ',num2str( bas