Ranter
Join devRant
Do all the things like
++ or  rants, post your own rants, comment on others' rants and build your customized dev avatar
Sign Up
Pipeless API
From the creators of devRant, Pipeless lets you power realtime personalized recommendations and activity feeds using a simple API
Learn More
Comments

Easy if you had exponentials before. You take some given number to the power of shit and get a given result. What's the shit? Fuck yeah, that's the logarithm.

junon28829dA logarithm is "how many digits are in this number", too.
At least you can use it that way.
Want to know how many digits are in e.g. a binary number (base2)?
log(x)/log(2)
What about hex (base16)?
log(x)/log(16) 
Root729259d@junon I used this extensively in basic to determine number length. I didn’t have a to_string method, and log is faster anyway!

Logarithms turn multiplication into addition, in the same way that exponentiation turns addition into multiplication.

//log base 10
function log(n){
lg = 0
while(n >= 10){
lg++
n/=10
}
return lg
}
My code, a little drunk so might be wrong whatever 
@Root I guess counting would only work with decompiled assembly code.
Because how many operations is log? And how many is int to string conversion? 
Root729255d@Lensflare @dfanelli You can make a good guess with log2 in assembly (leading zero counting) and adjust with a base10 comparison to get a very accurate log10 in only a handful of instructions.
Don’t have time to write it up in more detail right now. Sorry!
Int to string conversion takes more clocks, and then you need to scan the resulting length, too. 
@Lensflare @dfanelli @Root or use the old trick that you can isolated the LSB 1 by doing n & (~n + 1) (I think, something like that, it's been a while) and then use what's effectively an assembly binary search by essentially "folding" the number in halves to find that position of that 1. This gets you the position of that 1 in a handful of assembly instructions, proportional to the log of the length of the binary number (so, very very efficient).
A similar trick is used in Kernighan's algorithm, though without the binary search.
If you're processing numbers in reversed bit patterns, this is equivalent to finding an approximate log2. I've actually use this trick in a hot code path both in software and in hardware (on FPGA) and it gave a pretty nice speed bump (didn't have an integer log2 instruction or hardware primitive).
Logarithms give me a headache
rant
do you even math