The Nineteenth Byte

4:21 AM

@Anush I'm not entirely convinced the puzzle makers have considered the possibility of test cases designed to be so close you need humongous precision to distinguish them. Although possibly you can exhaust enough cases to prove that cannot happen. What I see is that 2^(7*x+3) >= 7*100^x + 3 so if the exponents are far enough apart the powers will always be too.

2 hours later…

Fatalize

6:43 AM

@Adám Mostly nothing, one of those symbols was unassigned, and the other was a predicate that was almost never used.

Finally bought an ErgoDox EZ keyboard; it's pretty amazing

primo

7:25 AM

"When you extend your finger, it doesn't go sideways, does it?"

yes, it does. because my elbows are approximately 55cm apart, and my wrist approximately 20cm apart

unless i want to hack my wrists outwards at a 30° angle

1 hour later…

8:31 AM

@ØrjanJohansen 2^(7*x+3) is not allowed as input is it?

@ØrjanJohansen but the overall point is that you can't solve the puzzle by evaluating the values explicitly

@Anush It's not meant to be an input, but a bound on one.

If x>=7y+3, then 2^x > 100^y.

right... but if you took logs to get x log(2) and 100 log(y) then you might be able to order them, right?

And stronger, 2^x > 7*(100^y) + 3.

@Anush Sure, assuming you don't run out of precision when comparing.

@ØrjanJohansen for all integers x between 1 and 100 log(x) is easy to distinguish

the problem is how to get to that form I think

They can be much larger than that.

My observation is just a first step: If you can show the exponents are that far apart, you know the whole power is.

8:36 AM

@ØrjanJohansen we will need to take logs repeatedly

Sure.

so I don't know what size the thing we take logs of will be in the end

are you sure it will be large?

It's not about being large. You can make it small. The problem is that it won't help if you end up having to compare two numbers that are so close you need more precision than you have memory.

And I don't know whether that can happen or not, and there's no obvious reason why it cannot.

Let's take 2^3^4^5 and 5^4^3^2

Perhaps it's possible to check all a^b^c cases and verify none of them are closer than 7 times each other unless they're equal. If so that should give an algorithm.

8:42 AM

we could rewrite the first as 5*4*3*log(2) and the second as 2*3*4*log(5)

No.

why not?

It's (3^4^5)*log 2 and (4^3^2)*log 5.

oh oops :)

so if we take logs again it gets messy?

Yeah although not too bad with two steps

8:44 AM

hmm.. nice puzzle :)

That does work with my observation, though. 4^5 = 1024 > 7*(3^2) + 3.

And then you know the former ends up larger, no matter what the rest of the bases are.

interesting

9:37 AM

@ØrjanJohansen at least we can agree it's not trivial :) Do you think it could make a nice ppcg challenge?

Well it might be tricky to check if implementations actually solve the problem...

Q: How can I encourage voting for non-golf languages?

9:59 AM

I would settle for a solution I believed might work currently :)

Neil

10:20 AM

@Giuseppe I came up with another solution based on A019446, but I still wasn't able to write it in Retina as I'd originally hoped

New Meta Posts

10:59 AM

I don't like golf languages, and I vote on solutions using them only if the solution has some extraordinary feature (like abusing a bug in the interpreter). How can I encourage people to vote this way in challenges I post? When tagging "code-golf", which I do pretty much 100% of the time, I disc...

2 hours later…

New Sandboxed Posts

12:32 PM

A: Sandbox for Proposed Challenges

Hungry Monster 9 My first challenge. Feedback is appreciated. A monster shaped like 2 is hungry and wants to become a 9. To do so he will eat food, that is shaped like the number 1, seven times. 0000000000 0000100000 0100000000 0000001000 0000020000 0100000000 0000000100 0010000000 0000001...

Leaky Nun

desmos.com/calculator/mzqr3dyavb

flawr

@Mods unfreeze please

2 hours later…

Veskah

2:48 PM

How do most people pronounce 05AB1E? "Oh-sah-bee", "Oh-sable", spelled out, a weird screeching noise?

Q: Intel prefixes instructions, checking optimisations problems

3:08 PM

I think "oh-say-bee" is the preferred

Adám

3:58 PM

three hundred and seventy-one thousand four hundred and eighty-six

New Main Posts

Q: The Nth Gryphon Number

I came up with a series of numbers the other day and decided to check what the OEIS number for it was. Much to my surprise, the sequence did not appear to be in the OEIS database, so I decided to name the sequence after myself (note that someone else who's a lot smarter than me has probably alre...

code-golf sequence

DJMcMayhem

4:18 PM

@AdmBorkBork I've always said "oh-sah-bee" in my head

New Main Posts

I wanted to learn more on ptrace's functions with x86_64 binaries, disassembling instructions. The goal is to check if a byte is one of instructions prefixes. I found some information in the Intel® 64 and IA-32 Architectures Software Developer’s Manual (volume 2, chapter 2). The section 2.1.1 I...

optimization x86-family

Anonymous

5:16 PM

@Veskah Definitely a weird screeching noise

5:31 PM

Hello

Mego, did you know that o and w in Actually (the prime factorization builtins) don't work on negative numbers anymore?

DJMcMayhem

5:52 PM

@flawr I'm a little bit late, but status-completed

Anonymous

@Sherlock9 Anymore? They did at some point?

@Mego Way way back when I wrote this answer

Anonymous

Oh yeah that was back in Seriously

Anonymous

The fact that factorization "worked" on negatives was a consequence of using trial division for factorization

Hrm hrm, ah well

commands.txt saying that o and w work on |a| still implies that it works, but that's easily fixed

Anonymous

6:43 PM

I never thought I'd say this, but React is quickly becoming my preferred web dev framework

Ooh, what prompted this conversion from ... I think you were using Flask for Axtell?

Anonymous

Yeah

Anonymous

I've been using React more, and my company is remaking our mobile apps in React Native

Anonymous

And it has so many fewer pitfalls

Anonymous

7:00 PM

I've been trying for an hour to add a simple checkbox to user settings

Anonymous

And only part of the problem is our overengineered frontend code

You just need simple programming. Like this.

Anonymous

@AdmBorkBork github.com/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee/…

+1 it has e.ps1

Anonymous

7:21 PM

The amount of nonsense I had to go through was absurd

Veskah

@Mego I didn't know you could program in tinnitus

Anonymous

Update DB schema, update SQLAlchemy models, update frontend models, add checkbox to JSX template, add it to serialized data, update route to handle new param, update controller to set new param in DB, update backend serialization to include param in data passed to frontend... And that's after all of the stupidity with updating my dev environment so that Axtell will actually run

Anonymous

Meanwhile in React with Redux it's just: update store to include new param, add new param to component, update mapStateToProps to pass param to component, update mapDispatchToProps to provide onChanged handler

Neil

7:37 PM

@Adám I'd say it's a sort of lime green sea green mix

Leaky Nun

8:20 PM

The first victim of Article 13