write a sigmoid function in matlab

To write a sigmoid function in MATLAB, you can use the following code:

main.m
function y = sigmoid(x)
% This function computes the sigmoid function for the input x

y = 1.0 ./ (1 + exp(-x));

end
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Here, the sigmoid function takes an input value x and returns the corresponding sigmoid value using the formula 1.0 ./ (1 + exp(-x)). The exp function computes the exponential value of the input and the ./ operator performs element-wise division.

Save the code in a file named sigmoid.m and call the function by passing the input value as an argument:

main.m
x = -10:0.1:10;
y = sigmoid(x);
plot(x, y);
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This will plot the sigmoid function for the range of input values specified.