Mac Dude

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12 years, 213 days

MaplePrimes Activity


These are replies submitted by Mac Dude

@acer Ok, now I am baffled. As you can imagine I am doing this in a larger context so it is always possible that some secodary effects are happeing; except that the package I want to add this to generally works. Regardless, in my context it does not work; either spewing out error messages during AddType or ignoring the new type and barfing at the type() statement.

I did verify that your example works in my Maple 17 as well (stand-alone at least).

Anyway, I'll double check & get back to you.

Thanks,

M.D.

@Athar Kharal Please show what you get. I ran Carl's example and it works, which is to say Maple can find the integral and IntTutor fires up when asked to (I don't know IntTutor so I haven't tried to actully do anything with it).

 

M.D.

@taro In the standard GUI it is easy: Select two input lines in an execution group and chose Edit>"Split or Join groups">"Split" (the detailed menu labels may be off but the principle is right, citing from memory here).

You join two groups in the same way: select across a boundary between two execution groups and Join. This can be useful: If you use the ditto operator (%), you really want to use it within one execution group so you do not run the risk of it pointing to the wrong thing if you evaluate lines of a sheet individually.

M.D.

The code snippet you provide has too many undefined names to really figure out what is going on.

You certainly have a missing semicolon at the end of the PMMmmf... statement. But you know that as Maple will have flagged it and refused to run the loop.


The dependency on i is a bit convoluted as it goes through rotorshift. Use print(name); to printout intermediate results to check whether that works right.

You are defining functions within the loop. I suggest you pull that out of the loop for efficiency. Also, it sort-of creates a new function every iteration which could cause some interesting effects. Furthermore you are depending on rotorshift acting like a global and being updated for each  call; not particularly good programming practise. I suggest you make that an argument.

As a general help in debugging loops you can insert print statements (like (print(name);) that will print the result. In large loops this helps. You can also make holding arrays for intermediate results and inspect these in the side panel.

M.D.

@nm Yes, the dual interface of Maple is confusing. However, it is not all bad. As a counter example: I used Maple in a teaching context last summer. My Maple files made up my script. This is where the Document mode came in handy, in fact it was close to an enabling factor. The script, which was live Maple code plus lots of text sections, would have been impossible to look at in worksheet mode. As it is I could even print it, for a textbook-like look.

For getting actual work done you really want to stick to worksheet mode and 1-d input. Note that you can change the input mode with the menu on top-left of the input window. C Maple Input is the setting for 1-d input. Also you can hit the [> button to get a 1-d input prompt. Independent of the mode of the sheet.

M.D.

This is an important question, in parts because we now do much more with systems like Maple than just symbolic derivations. I haven't gotten quite to that stage yet, although I likely will within the foreseeable future.

At this point I believe what you can do is saving things like vectors, matrices and arrays (large data sets with only a few names), to be read-in upon resuming a run. This leaves you with having to recreate variables which hopefully is less of a task. Some problems will not yield to such "factorization", however, so checkpointing a long calculation is something Maple should implement.

M.D.

Whar exactly do you mean by "closing a paragraph"?

The important entity in a Maple worksheet is the execution group. In worksheet mode with 1-d input, it is indicated by the line on the left side of the text. It is always "closed" at the end.

M.D.

@nm The observed behavior stems from ?foo or ?pi doing the same thing as when you type foo or pi into the search field within the help window. It is a case-insensitive search. Now clearly, in Help you want the search to be case-insensitive. One may argue that ?something should only trigger on valid Maple names, that seems worth considering.

My pet peeve? Pi in Maple prints as π (lowercase pi). The unrelated name pi prints as π also. Should'nt "the" pi be called pi in Maple input??

At the end, these things are decisions one had to make during building Maple and one learns to live with as user. There are in reality much more significant issues to address than these.

M. D.

 

 

@Alejandro Jakubi I have, more-or-less, described the situation as I see it. I can do my share of submitting bug reports, suggesting improvements etc., but ultimately I cannot change a company's behaviour (and/or their revenue model) other than by stopping to use their product.

But none of these rants liberate me, or anyone else, from due diligence and accepting my responsibility in verifying results I get.

M.D.

@dharr Well, N is infinity for each term and can in fact be factored out trivially.

The problem is more likely that Maple does not know what limit(sigma(n),n=infinity) is, and it returns it unevaluated.

You can get around the eval problem by replacing sum with add. But add cannot be taken to the limit N=infinity.

M.D.

@Alejandro Jakubi Well, even on re-reading it I do not see my reply as making any suggestion as to whether the op's request made sense or not. With the info provided, how could I?

In my work environment (and many others' also), "support" usually boils down to money, unless stated otherwise. Since the op appears to work in an academic environment and is looking for support for a student, the question what level of support was asked for (implying monetary) seems still a reasonable one to ask. Certainly other forms are conceivable, but would need to be outlined with a few more specifics.

Thinking more about it, I'd probably start by writing down a rough outline of what the student's project is supposed to achieve and what kind of upport is really needed. Also, and importantly, one would want to make the case where Maplesoft would gain from such support whatever kind it is. Would a case study be of interest to Maplesoft? Would this project potentially lead to new packages not extant right now (which, if general enough, I would consider a stronger case). or?? And we should not fool ourselves, even if this would be more like a kind-of cooperative programming project or whatever, the company will evaluate the associated costs and will need to ask itself what the return, real and potential, will be.

I still suggest that the op needs to talk to someone within Maplesoft itself. This forum can be a conduit (it was for me when I was planning my accelerator physics course), but how is he going to find out what would make this interesting to Maplesoft and what their conditions would be? I do think the fact that no one from Maplesoft replied indicates that the original question was asked maybe somewhat too broadly and with too little detail. We know a good number of Maplesoft people read this forum, and I am slightly disappointed that no one at least was willing to make some helpful remarks to the op.

Mac Dude.

There is a line in the concluding paragraph of the paper: "... and we completely trusted the results by ...". This mindset produces the ranting about CASs making mistakes. Do they? Of course they do. Do I make mistakes? (Well, never mind...)

The point is not to be lenient; bugs can and should be exorcised even if occasionally at great expense. But as a user of any tool it my responsibility to verify it is (a) the appropriate tool and (b) the results it produces are correct in the context of the problem posed. And, incidentally, running the same algorithm through two different CAS, while maybe useful, is not a proof of correctness, not by far.

No CAS can replace thinking. No program can be "trusted" if the results are mission-critical. In that sense the paper reveals more of the attitude of the authors than of CAS systems. And, are we really that surprised that their bug report did not have any discernable effect? To be fair here, these systems are complicated and implementing a fix may not be a trivial matter in this case. (Added in edit: Somewhere I read Wolfram said they fixed this one in Mma 10.<something>. But now apparently other, similar ones are showing up. Strange)

Just my $0.02

Mac Dude

Edit: Fixed up the English in places and a whole bunch of typos. Added comment about Wolfram supposedly fixing the bug in latest release of Mma 10.

I am not an expert with sed, but I assume the semicolon trips things up.

But, why don't you read in your parameter file in script.mw? If you want to read in valid Maple assignments, you can use "parse()" on the string you just read in to execute it as a Maple statement.

M.D.

 

@Fairouz A cursory look in the Web would make me believe that you can embed a Flash movie or a Quicktime movie in a pdf, at least if you use recent versions. But you are on your own here as far as I am concerned, I have never done this.

M.D.

@andhaga I am not sure about your diff(V(y),y) term... y is defined  as y(t) above and Maple won't differentiate against a function without some specific incantations. Using a name (y) both as function and as variable is stringly discouraged, you are going to confuse yourself and maybe Maple also.

As far as correctness is concerned (besides the issue with y): neither your de nor the solution offered look like a pendulum equation to me. But there is truckloads of info on pendulum equations on the web, I'll leave it to yo to figure out what it should look like.

M.D.

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