@DarkMath I'm guessing this has to do with the capabilities of solve. solve(x^2-9) gives 3,-3 but solve(sin(x)) is lazy and gives only 0. solve(sin(x),allsolutions) gives Pi*_Z1 with about (_Z1) showing _Z1 is an integer. So that could be used with some additional range checking. But solve(sin(x),useassumptions) assuming x>-3*Pi/2,x<3*Pi/2; returns only zero.

Maple's Dirac help page certainly suggests it uses the rule you specfied, so I think it is not unreasonable to expect Maple to do better in this case.

@vs140580  Not really your question, but perhaps the Iterator package does what you want, esp Iterator:-permute.

When I run the worksheet there us no error (Maple 2017)

@Adam Ledger  
 

Download args.mw

@acer  @J F Ogilvie As you may know, the CODATA 2018 values relesed last year have many constants now exact (Planck's constant, Avogadro's constant, elementary charge, gas constant, Boltzmann's constant, speed of light (constant for a long time)), so the effort of an update now means very few changes will need to be made in the future.

@Carl Love i like that better, though the error message is still a bit obscure. Perhaps the type should be "listcontaining" rather than "speclist" ...

@Axel Vogt 

Fac:=n->n!

:)

@tomleslie Thanks. I saw the code (only procedure definitions) but missed the system calls. Interestingly, the output of the procedure definition "monspt" in question shows it was using ListTools:Reverse by default.

@Lisa6 There is insufficient information.

@Lisa6 You must be running more code than you are showing. I can't run the code because I don't have a version with the convex package; you don't say which version of Maple you have.  @tomleslie and I agree that the message is very clear, so you will have to upload a worksheet that demonstrates the error.

@Preben Alsholm You're right. Actually now when I rerun the OPs worksheet (Maple 2017) I'm not getting any errors; it's just slow, Not sure why I thought that.

@Anthrazit  I hadn't thought of the case where the two units didn't have the same zero; that does seem to violate the ideas of quantity calculus. Actually, I am more worried about the case where you can convert 0 K to 0 kg. That's why I used the word "debatable"

Notice that there was a missing space  or * between Pi and (ex6r)^2 so these weren't being multiplied. @Kitonum fixed this up in his answer. The fact that (4)^2 wasn't automatically simplified is a clue that something is not quite as intended.

@isifesai Your solve syntax needs to be

solve({cat(eq, 1 .. 62), seq(a[i] >= 0, i = 1 .. 26), seq(b[i] >= 0, i = 1 .. 12), seq(x[i] >= 0, i = 1 .. 24)}, [seq(x[i], i = 1 .. 24)])

but you have many more equations and constraints than variables, and you don't get any solutions.

@fatemeh1090 The .pdf result has x__2 in, which in the worksheet I did, is expressed in terms of alpha, beta etc. It is not easy to check if they are the same.