在Matlab中绘制隐函数

我想这可能正是你想要的。我指定f、g和h为匿名函数,并使用quad2d来估计二重积分的值。

%% Input bounds
a = 0;
b = 1;
c = 0;
d = 2;

%% Specify functions

% vectorize function as a prerequisite to using in quad2d
f = @(x,t,w,n) exp( -(x.^2 + t.*w + w.*x)./n) + exp(-(t.^2 + t.*x.^2 - 2.*t.*x)./(2.*n));

% keeps x,n fixed in function call to f(...), varies a < t < b; c < w < d
g = @(x,n) quad2d(@(t,w) f(x, t, w, n), a, b, c, d);

% wrap functions into h
h = @(x,n) log(g(x,n)/g(-x,n));

%%

figure();
hold on % keep lines

x_range = linspace(-1,1);

for n = 1:5
    plotMe = zeros(1, length(x_range));
    for iter = 1:length(x_range)
        plotMe(iter) = h(x_range(iter), n);
    end

    lineHandle(n) = plot(x_range, plotMe);
end


 legend(lineHandle, {
     ['N: ', num2str(1)],...
     ['N: ', num2str(2)],...
     ['N: ', num2str(3)],...
     ['N: ', num2str(4)],...
     ['N: ', num2str(5)]...
     }...
 )