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Question: Why is `ArrayTools[GeneralOuterProduct]` extremely slow???

Question:Why is `ArrayTools[GeneralOuterProduct]` extremely slow???

sursumCorda 1239 Maple 2023
outerproduct
March 09 2023
0

The new command ArrayTools[GeneralOuterProduct] (introduced in Maple 2021) computes the generalized outer product of two rtables, and again, there exists a similar function Outer in Mma (cf. the end of this question). But in practice, it appears that this Maple command is not so fast as Mma's one. To begin with, we need to generate four lists: w, x, y, and z. Our goal is forming all possible combinations of the lowest‐level elements in a nested structure (rather than a flat structure). Now let us start the test.

In Mathematica (the real time is about 0.784176): 

And in Maple (the real time is about 199.880): 
 

> 

restart;
> 

w := [`$`](0 .. 1e4):
x := [`$`](0 .. 2e3):
y := [`$`](0 .. 3e2):
z := [`$`](0 .. 4e1):
> 

"time[real]((p1:=MmaTranslator:-Mma:-ReplaceRepeated(convert(ArrayTools:-GeneralOuterProduct(convert([w,x],Array,fill=NULL),()->`if`(nargs=2,`[]`(args),NULL),convert([y,z],Array,fill=NULL)),listlist),[]=NULL)))"

199.880

 (1)
> 

"time[real]((p2:=(s4->(s3->(s2->(s1->`[]`(s3,s1))~(s2))~([y,z]))~(s4))~([w,x])))"

7.699

 (2)
> 

p3 := parse(StringTools:-CharacterMap("{}", "[]", FileTools:-Text:-ReadFile("E:/data.txt")))

evalb(p1 = p2 and p2 = p3) = trueNULL


 

Download Outer.mw

As you can see, Maple and Mathematica returns identical results (∵p1＝p3); nevertheless, Maple consumes too much time: the ratio is 199.880/0.784176 ≈ 254.892. (What a wide gap between them!) 
So, is there any possibility of speeding up Maple's ArrayTools:-GeneralOuterProduct? Or any ideas of obtaining the same results in Maple efficiently?

Explanatory notes. Here is an illustrative animation: 
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