I was trying to debug my implementation of Dijkstra's algorithm and ran into this J crash:
(AoC Day 15 spoiler ahead -- well sort off, the solution is not entirely correct, hence the debugging :p) ts is a snaking path of 0's from 0 0 to 9 9, and try1 (should) implement Dijkstra's algorithm for finding a path with a minimal sum of the nodes crossed. Something in my implementation is wrong (hints welcome), but the J bug turned up when I wanted to debug this approach by adding a \ to keep intermediate results, which causes a bus error: try=: [: ([ + 2 <./\ padrifshort)&.>/\@|. [: </. 0 (<0 0)} ] ts =: 0 1 0 0 0 1 0 0 0, (7 9$9$0 1), (0 0 0 1 0 0 0 1 0) try1=: [: ([ + 2 <./\ padrifshort)&.>/@|. [: </. 0 (<0 0)} ] max=: 2e9 padrifshort=: ]`(max (,,[) ])@.(>&#) try1 ts NB. "works" no crash, but result is wrong. ┌─┐ │2│ └─┘ try ts Bus error NB. J crashed. For an explanation of the code, see ( http://www.jsoftware.com/pipermail/programming/2022-January/059538.html). My J version: JVERSION Engine: j903/j32/android Release-a: commercial/2021-12-17T11:10:19 Library: 9.03.08 Platform: Android 32 (armeabi-v7a) Installer: unknown InstallPath: /mnt/sdcard/Android/data/com.jsoftware.j.android/files Contact: www.jsoftware.com Jan-Pieter ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
