logistic-vs-tanh.m

x = -10:0.01:10;

function y = logistic(z)  
  y = 1 ./ (1 + e.^(-z));
end

function y = logistic_derivative(z)  
  y = logistic(z) .* (1 - logistic(z));
end
  
y1  = logistic(x);
dy1 = logistic_derivative(x);

y2  = tanh(x);
dy2 = 1 - tanh(x).^2;

figureplot(x, y1, "-;logistic(z);", x, y2, "-;tanh(z);");
figureplot(x, dy1, "-;logistic derivative;", x, dy2, "-;tanh derivative;");