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6:37 AM

@Adám Shouldn't this give 1?

(2(⍱/∨⍥(0∘∊)⍱⌿)⊢) 3 3⍴ 0 0 1  1 1 1  1 1 1

@JoshD Actually I already have positions of zeroes and the dimension of the matrix shouldn't exceed something like 30, but I always thought that checking relative positions of zeroes in a matrix would be simpler or more efficient, at least

Master Quiz

6:58 AM

Wait, I might have badly proposed what I was looking for.
f ← ⍉⍱⍥(∨/∘,0 0∘⍷)× ⍝ This is my correct (and unefficient solution)
It returns 0 if the matrix contains two consecutives 0s (It return 1 in this matrix 3 3⍴ 1 1 0 0 1 1 1 1)
@Adám Is something like this correct?
⍉⍱⍥(∨/⍤∊2⍱/⊢)⊢

Adám

@MasterQuiz Ah, you mean to say it should be (2(⍱/∨⍥(1∘∊)⍱⌿)⊢) — yes.

@MasterQuiz (just use multiple messages instead of a single multi-line message. They'll look like a single message)

@MasterQuiz The transpose is expensive. You don't need it.

Master Quiz

@Adám Oh thanks, I was about to ask this

Adám

And a ravel (your ∊) has a cost too, as it needs to copy all the data. ∨/∊ and 1∊ are equivalent.

One thing I didn't do was make my solution work for non-Booleans, but of course, that's just 0∘≠

Master Quiz

What about the difference between putting 0s in a matrix (that actually can be already a boolean one) and than use the function above and doing some calculations with the vector of positions?

Adám

I'll try it.

Master Quiz

7:17 AM

Considering that, for the moment, I expect the matrix to have 12≥≢m so the positions will be around 24. (If the dimension of the vector can affect the efficiency of one method or the other one)

@Adám This is working (I think) but it seems a lot inefficient {(⊂0 1)(⊂1 0)⍱.∊⊂∘.-⍨⍵}

7 hours later…

Stack Exchange Feeds

2:05 PM

Q: Resuming execution after conditional breakpoint in Dyalog APL

In a previous question I asked about how to set a conditional breakpoint in Dyalog RIDE, and the accepted answer works as advertised, by creating a guard statement with an empty function call as the body. Execution will be halted on the expected line when the condition is met. However, this being...

Q: Access same row/column in each array in nested arrays in Dyalog APL

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apl dyalog

2 hours later…

Adám

3:51 PM

@MasterQuiz 1∊∘.-⍨∊(0 1)(1 0)⍨ is probably as good as it gets, but right, O(n²) is probably not good unless there are very few 0s.

Adám

4:21 PM