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module SPCore
# Provide simple saturation methods, that limit input above the given threshold value.
class Saturation
# Sigmoid-based saturation when input is above threshold.
# From musicdsp.org, posted by Bram.
def self.sigmoid input, threshold
input_abs = input.abs
if input_abs < threshold
return input
else
#y = threshold + (1.0 - threshold) * mock_sigmoid((input_abs - threshold) / ((1.0 - threshold) * 1.5))
y = threshold + (1.0 - threshold) * Math::tanh((input_abs - threshold)/(1-threshold))
if input > 0.0
return y
else
return -y
end
end
end
# A Gompertz-sigmoid-based saturation when input is above threshold.
def self.gompertz input, threshold
a = threshold
b = -4
c = -2
x = input.abs
y = 2 * a * Math::exp(b * Math::exp(c * x))
if input > 0.0
return y
else
return -y
end
end
end
end
Version data entries
9 entries across 9 versions & 1 rubygems