gramian

%% Math %%

si = @(x) sin(x) ./ (x + (x==0)); % cardinal sine without pi multiplied argument

hsin = @(x) 0.5 * (1.0 - cos(x)); % haversed sine

hcos = @(x) 0.5 * (1.0 + cos(x)); % haversed cosine

sigm = @(x,k) 0.5 * tanh(0.5 * k * x) + 0.5; % sigmoid function to (exp(-kx)+1)^-1