Csound variables

The first letter of a variable determines its type:

i: They're set at the initialization of an instrument (init pass).
k: control variables. Updated each control cycle
a: audio variables. Unlike control variables, they are a vector whose size is ksmps. Usually, they store audio samples. Updated each control cycle
p: score parameter fields
S: string variables

Global variables: see initializing global vars etc.

Converting between types

a to k

downsamp, by default, takes the first value of an a-variable array and assigns it to a k-variable. With the iwlen parameter, a length of the sub array can be defined of which the avarage is taken.

max_k finds the max or min value in the a-array.

rms

samphold

k to a

avar = kvar: all elements in avar are set to kvar's value. upsamp is equivalent, but less efficient.

interp which is equivalent to avar=a(kvar).

i to k

kval = ival

k to i

Problematic because the kvar might not be initized at the init pass.