mlochbaum / bqn-libs

Informal collection of BQN utilities

Array programming language user, designer, and implementer. Co-developer of Jd and former performance specialist at Dyalog. Skilled with a yo-yo. See my Github homepage for an overview of the repositories here. Also working on ngn/k at Codeberg.

bqn-libs's Issues

Unable to use Factor on certain numbers

I was trying to get an iterator of factorizations, and got an error for certain numbers. I was using CBQN, and ran

p ← •Import "primes.bqn"

•Out •Repr p.Factor 7718429
•Out •Repr p.Factor 255
•Out •Repr p.Factor 256
•Out •Repr p.Factor 258
•Out •Repr p.Factor 259

•Out •Repr p.Factor 257

When I tried to run it, I got

2081‿3709
3‿5‿17
2‿2‿2‿2‿2‿2‿2‿2
2‿3‿43
7‿37
Error: ´: No identity found
/home/alexdikelsky/euler/prob_451/primes.bqn:106:
    Pow ← Mul{𝔽´𝔽˜⍟(/2|⌊∘÷⟜2⍟(↕·⌈2⋆⁼⊢)𝕩)𝕨}
               ^
/home/alexdikelsky/euler/prob_451/primes.bqn:115:
    C ← { 𝕊a: s MR a Pow d }  # Is composite
                   ^
13: source unknown
12: source unknown
/home/alexdikelsky/euler/prob_451/primes.bqn:116:
    0 {𝕨<⟜≠◶⟨1,C∘⊑◶⟨+⟜1⊸𝕊,0⟩⟩𝕩} Witnesses 𝕩
        ^^^^^^^^^^^^^^^^^^^^^
/home/alexdikelsky/euler/prob_451/primes.bqn:116:
    0 {𝕨<⟜≠◶⟨1,C∘⊑◶⟨+⟜1⊸𝕊,0⟩⟩𝕩} Witnesses 𝕩
    ^
9: source unknown
8: source unknown
/home/alexdikelsky/euler/prob_451/primes.bqn:91:
    c◶⟨(ט¯1⊑p)⊸<◶1‿MillerRabin, 0⟩ 𝕩
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
6: source unknown
5: source unknown
4: source unknown
/home/alexdikelsky/euler/prob_451/primes.bqn:159:
    2⊸⌊◶⟨!∘"Can't factor 0", 2‿0⊸⥊, IsPrime◶⟨FactorTrial, ≍˘≍⟜1⟩⟩ 𝕩
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2: source unknown
1: source unknown
factor.bqn:9:
  •Out •Repr p.Factor 257
               ^^^^^^

It looks like 257 doesn't work, but the numbers around it work fine. 257 is prime. Factoring the next prime (263) works fine.

csv.bqn doesn't handle empty fields at the end of data correctly

Hi,
I found Split in csv.bqn converts "ab,,bc," to ⟨ "ab" ⟨⟩ "bc" ⟩ instead of ⟨ "ab" ⟨⟩ "bc" ⟨⟩ ⟩.
And it emits the following error by "ab,,bc,,":

Error: ⊔: ≠𝕨 must be either ≠𝕩 or one bigger (5≡≠𝕨, 3≡≠𝕩)
test/../csv.bqn:22:
    (0∾s/+`e<n) ⊔ (d(¬⊸×-⊣)+`s) ⊔ 𝕩
                ^
test/csv.bqn:19:
  ! ⟨⟨"ab",⟨⟩,"bc",⟨⟩,⟨⟩⟩⟩ ≡ c.Split "ab,,bc,,"
                               ^^^^^

So I came up with the following.

$ diff -u csv.bqn csv-rev.bqn
--- csv.bqn     2023-07-20 07:32:01
+++ csv-rev.bqn      2023-07-20 14:19:51
@@ -24,7 +19,7 @@
   e ← ≠`q       # Escaped characters
   s ← e<c∨n     # Split points
   d ← s∨q>»e<q  # Characters to be dropped
-  (0∾s/+`e<n) ⊔ (d(¬⊸×-⊣)+`s) ⊔ 𝕩
+  (0∾s/+`e<n) ⊔ (1++´s)↑(d(¬⊸×-⊣)+`s) ⊔ 𝕩
 }
                                                                                        
 # Parse list of lines, e.g. from •file.Lines

This seems to work well. But I don't know if it's the best solution... 😄

Small primes not called prime by IsPrime

When I run

primes ← •Import "primes.bqn"
•Out¨ •Repr¨ (primes.IsPrime 2+(↕30)) ∾¨ 2+(↕30)

in CBQN, I get that 2, 3, 5, 7 are not primes. I'm using the most recent version of bqn-libs.