+++
title = "μ function"
author = "Yann Herklotz"
tags = []
categories = []
backlinks = ["2e1b5a", "2e1b1"]
forwardlinks = ["2e1b3", "2e1b2a"]
zettelid = "2e1b2"
+++

The μ function only appears in loop headers, and it selects the initial
and loop carried values for the variables in the loop. It does not come
with a condition, and instead works exactly like a φ function, where the
left hand value is the initial one, and the right hand value is the
loop-carried value.

    x2 = μ(x1, x3)

Means that the initial value for x2 is x1, and that the consequent
values for x2 is the value of x3.