Fast Local Extrema

Fast local extrema calculation

Calling x = extrema(X) returns a logical array whose elements are 1 (true) when a local extrema is detected in the corresponding element of 'X'. The function operates along the columns of 'X'. An example of the use of this function is:

t = 2 * pi * (0 : 1 / (1000 - 1) : 1)';
X = [t, exp(-t / 2) .* sin(10 * t)];
k = extrema(X(:, 2));
figure
hold on
plot(X(:, 1), X(:, 2))
plot(X(k, 1), X(k, 2), 'o')
axis equal