Math
Natural logarithm. Use it when you need logarithmic scaling or curves; the input should be positive.
Input should stay positive for predictable results.
ln(1.0+4.0*param(2))
For pitched oscillator functions, X already contains the current MIDI note pitch and transpose information. Prefer saw(X), sin(X), or pwm(X, 0.4) unless you intentionally want an octave or ratio shift such as 0.5*X or 2*X.