| ts:{(./!x)!,,/((./.x)*\:(./.y))} | |
| sp:{+/((,/.x)*(,/.y))} | |
| dim:1025#0 | |
| dim[2]:1 | |
| dim[4]:2 | |
| dim[8]:3 | |
| dim[16]:4 | |
| dim[32]:5 | |
| dim[64]:6 | |
| dim[128]:7 |
| Syntax | Name | Description | Example | Output | |
|---|---|---|---|---|---|
| +/x | Sum | Sum all value in x | +/1 2 3 4 5 | 15 | |
| -':x | Deltas | Pairwise differences in x | -':1 2 3 4 | 1 1 1 1 | |
| |+x | Rotate matrix | Rotate x counterclockwise | |+3 3#!9 | (2 5 8;1 4 7;0 3 6) | |
| x@<x | Sort | Sort x | {x@<x}@8 3 7 1 | 1 3 7 8 | |
| ?x,y | Set union | Unique elements from x and y | ?"abac","adob" | "abcdo" | |
| x^x^y | Intersection | Common elements from x and y | {?x^x^y}["abac";"adob"] | "aba" | |
| x|-x | Absolute value | Absolute value of x | {x|-x}@-1 | 1 | |
| */y#x | Power | x in power of y (y>0) | {*/y#x}[2;5] | 32 | |
| y@(#y)!x+!#y | Rotate left | Rotate y by x elements to the left | {y@(#y)!x+!#y}[3;"abcde"] | "deabc" |
| import { Advent, f } from "advent"; | |
| const { compute, computeCheck } = await Advent({ day: 2 }); | |
| compute(2, async (input) => { | |
| const data = input.parse(f.nl(f.tok(f.str()))); | |
| let ans = 0; | |
| for (const [them, us] of data) { |
Let's reduce the operations on rank-1 arrays (lists) down to very basic functions.
Two views on lists:
The first view gives ↕n, i⊑x and x⊏y, which correspond to the identity function, application
and composition, and also gives f¨x and x f¨ y.
The following question was asked on the APL Orchard chatroom (https://chat.stackexchange.com/transcript/message/59923809#5992380):
so I was reading https://xpqz.github.io/learnapl/iteration.html a bit ago and was confused by the binary search example, so wanted to test. the numbers I'm seeing for linear search are both nothing like his and don't make a lot of sense. I did randInts ← 100000 ? 100000 and compared execution times of randInts ⍳ 1, 19326, and 46729. the return values of those are 94438, 1001, and 1 respectively. the execution times are 0.13ms, 0.47ms, and 0.12us respectively. can anyone explain what's happening?
Obviously, we can't recreate the randInts exactly, but let's run a few timed iterations:
I had a vague idea about an operator that would ease working with value tolerances and ranges. During our ride up Mount Etna, I by chance had the pleasure of sitting next to Geoff Streeter. We started discussing some things, and before long I had my laptop out and we were prototyping a new operator.
I discussed my idea with Nick Nickolov, who told me that being a fan of ⎕CT←0, he has considered ≈ to denote tolerant equality. I think we then naturally would want ≉, and ≲, and
| what k4/k7 k9 example result | |
| --------------------------------------------------------------------------------- | |
| each-left a f\:b a f\:b (!3)*\:!2 (0 0;0 1;0 2) | |
| each-right a f/:b a f/:b (!3)*/:!2 (0 0 0;0 1 2) | |
| fold f/v f/v */6 7 42 | |
| fold w/initial a f/v a f/v 7*/11 13 1001 | |
| scan f\v f\v -\1 1 1 1 0 -1 | |
| scan w/initial a f\v a f\v 3-\1 1 1 2 1 0 |
Sometimes it is really nice to just take a quick look at some data. However, when working on remote computers, it is a bit of a burden to move data files to a local computer to create a plot in something like R. One solution is to use gnuplot and make a quick plot that is rendered in the terminal. It isn't very pretty by default, but it gets the job done quickly and easily. There are also advanced gnuplot capabilities that aren't covered here at all.
gnuplot has it's own internal syntax that can be fed in as a script, which I won't get into. Here is the very simplified gnuplot code we'll be using:
set terminal dumb size 120, 30; set autoscale; plot '-' using 1:3 with lines notitleLet's break this down:
Here are all of the resources mentioned by Deconstruct 2017 speakers, along with who recommended what. Please post a comment if I missed something or have an error!