The APL Orchard

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Adám

7:57 AM

@nathanrogers Look at the 50 Years of APL section from Dyalog '16 on Dyalog TV.

Adám

8:27 AM

@arcfide A challenge for you!

5 hours later…

J. Sallé

1:42 PM

Hey guys, if I have two 2-element vectors and need to do v1[1]>v2[1] & v1[2]<v2[2], is there a shorter way than using bracket indexing?

if it's relevant, one of the vectors will always have the same 2 elements

dzaima

@J.Sallé 5 2 (2⊃2∧/(<,>)) 1 5?

er, those parentheses around <,> aren't needed >.<

J. Sallé

That might work, I’ll get back to it in a few minutes

2 hours later…

nathan rogers

3:52 PM

Adám

@J.Sallé v1 (∧/¨(>/,¨∘⌽)) v2?

J. Sallé

@Adám ooooooh this is better, I think

Adám

@J.Sallé If you have them as a matrix (↑v1 v2), you can do ∧/>⌿0 1⊖↑v1 v2

J. Sallé

Might be even better

Adám

Adjust accordingly if your matrix is transposed.

J. Sallé

4:03 PM

I'm trying to solve the challenge you linked btw

ngn

4:29 PM

@J.Sallé another way: 1 ¯1≡×v1-v2 or 1 ¯1≡∘×-

J. Sallé

@ngn don't know if I can incorporate that, I'll try

ngn

@J.Sallé do v1 and v2 represent intervals? is it important that it's < and not ≤?

J. Sallé

@ngn no and yes

I think I'm gonna try another approach. I'm trying to do it recursively but there's a lot of "edge cases"

ngn

@J.Sallé what problem are you solving?

J. Sallé

4:45 PM

@ngn the one Adám linked above

2 hours later…

nathan rogers

6:50 PM

https://tio.run/##nVTBbtNAEL33K@ZoKym1k55Qo1bizBdEOaztabxgr6P1hiatcgFUtaWWQJyREAiRG4c2AkXi0k/ZHwmzu3aTFioQlrzZ7M7Ovnnvjdko206mLCuGqxWArj5AzGTCBcsg4RJjxQtRPoKjFAWwJMEEVAEMYsyyNpRsCl3otmHLHUUWp8AV5iBRjaUAXsKu2e@YoQu7ZujUwUcpp2gmEViWgUA@TKNCcjG0yUuKIgAl6NO3@vT9LnR0dR1CADffzBhAMwfYqhMOURGyjJcKikMC@4zFKJTLBtHUwDfZbVYqQqUI8Vg2IXDvoaSU4ok9TBjgxNNnX3du5p6nL14RFl0tfX3@JfJp2Qv2It/fiQzWatEyN8w2UZmrBE5UTRtyWpAQsfi5kjRAIUEykRQ5YD5S01sy4OGHslNmA8@hC/b0@SfMlYXwI@gRjr6t3GHaqKVaDh5ToL2xJke/eW3WvZqqBpdPB2d32a1hUjAcSjtZ0L5NZWHQf335XVdzinCTfcfVbR42GmVTy8gLlo3RSFUrsZaiZRjZJolrmQQe/VGjh7lxt1hIlnN98dIj5YgUU7/f8sJ…

A non recursive non stack based recursive backtracking algorithm.

this was a really cool prollem

removed

why are these links empty?