The Nineteenth Byte

@NewMainPosts no

@Bas yes

I start. beep

I really need to do that in a bot sandbox.

@zyabin101 Okay. beep boop

crash

@zyabin101 I'm bad at this game

12:18 PM

@Lembik Hi?

@CᴏɴᴏʀO'Bʀɪᴇɴ hi, you're hard to ping. Everything after C breaks

@Bas Indeed. Just do @C + tab

@CᴏɴᴏʀO'Bʀɪᴇɴ I wanted to change my name to C to prevent people from pinging you but then I remembered the 1 month namechange rule

Q: Calculate the Kronecker Product

XD. then it's just @C + tab * n

New Main Posts

0

Related, but very different. In the examples below, A and B will be 2-by-2 matrices, and the matrices are one-indexed. A Kronecker product has the following properties: A⊗B = A(1,1)*B A(1,2)*B A(2,1)*B A(2,2)*B = A(1,1)*B(1,1) A(1,1)*B(1,2) A(1,2)*B(1,1) A(1,2)*B(...

code-golf math linear-algebra matrix

12:20 PM

@CᴏɴᴏʀO'Bʀɪᴇɴ People are lazy and will eventually forget about you

@Bas Also, a name needs at least three chars.

@zyabin101 Damn. Rip evil master plan

@Bas ;)

I won't be so easily forgotten.

This keeps cracking me up

^ :D

12:27 PM

@Sp3000 Hello!

@Bas The <center> cannot hold it is too late.

Damn very slow 'net connection!

@Sp3000 I haven't managed to write the matrix mult challenge

one question is should it be multiplication over the integers or something simpler?

TimmyD

12:46 PM

@Bas Reminds me of House of Leaves

I tried to install Anaconda (actually its small no-package niece Miniconda) and all I got was megabytes of disk space wasted. I am never able to use conda.

Now I have to reinstall Python FROM THE VERY BEGINNING (as I uninstalled the CPython distro for conda to be available from the system PATH, as a second variation) ;;;_;;;

1:06 PM

@Lembik Does it matter? Or is the answer somehow different if you work in, say, integers mod 2 or something?

Nathan Merrill

1:30 PM

is there a good reason python uses __magic__ for their magic methods as opposed to just magic

a.add(b) is much more readable than a.__add__(b)

Kenny Lau

Since when did answers in Jelly become unpopular?

1:48 PM

@Sp3000 I think the answer might be the same but the code could be a lot faster. How are you going to search for solutions if you use integers?

Well the answer you get shouldn't really depend on the contents of the matrix, right? As in it should just give a list of intermediate steps and how to obtain each entry in the resulting matrix

@Sp3000 right but I am trying to imagine how you are going to solve the problem of finding the minimum number of multiplications

@Sp3000 do you have any ideas?

Not any good ones, no, but I was assuming that was part of the challenge :P

it is :)

I mean, in the worst case you could just brute force all possibilities for a solution

Obviously not the best way

1:52 PM

so one idea I have works mod 2 but not with integers

@Sp3000 how will you check a given solution is correct even if you use brute force?

As in that it's optimal or that it's a valid solution?

brute force is OK for small n :)

@Sp3000 that it's valid

basically.. what is a brute force solution?

i object

@Agawa001 ?

Check that it indeed outputs C_{1,1} = A_{1,1} B_{1,1} + A_{1,2} B_{2,1} etc

1:54 PM

bruteforce isnt ok unless for np hard problems

@Sp3000 but you can't check all A_{i,j} if it's allowed integer entries

that's the problem

you can if it's only allowed zeros and ones

Well you don't care about the actual values right? As in you don't sub A_{1,1} for a number, just treat it as A_{1,1}

@Sp3000 that sounds hard :)

I'm interested - if a Python install for Windows is repaired, will any packages installed before the repair remain?

Well you wanted a possible approach, and that's the only one I have in mind atm :P

1:56 PM

(Repairing an install is the Windows Installer's way of saying "to re-install".)

@Agawa001 It's good for checking your better approach is correct for at least small values though

@Sp3000 I like the idea but I am not sure how easy it would be to prove your solution is equivalent to A_{1,1} B_{1,1} + A_{1,2} B_{2,1} in code

\o/ @RenderSettings you're back!

without enumerating alll possible entries

@Sp3000 how ?

1:57 PM

Apparently not. Dam.

ah, make a comparative with the outlets of two approaches

@Lembik Er... maybe I'm not saying this clear enough. Imagine starting with 8 variables a,b,c,d,e,f,g,h and I define x = a(f-h), y = (a+b)h. Then it's pretty easy to check that x+y = af - ah + ah + bh = af + bh

RenderSettings

@zyabin101 im always already back

He's always here

@CᴏɴᴏʀO'Bʀɪᴇɴ Ah, you are back. Did you see the countdown I announced for Nested Programs?