Return a function of the form $$c \left(1+\epsilon + \sin\left(\frac{2 \pi (t-\tau)}{365}\right)\right)^p$$ where \(c\) is a normalizing constant, and
\(\epsilon \geq 0\) or
floor\(\tau\) or
phase\(p\) or
pw
Usage
# S3 method for class 'sin'
make_function(opts)