Bug in Symbolic Solver

[Werner_E]

This thread was broken off of this original topic thread.  

BTW, does anyone know, why Primes symbolic can't solve this simple system of equations?

The new symbolic in Prime 6 claims that no solution was found and the legacy one (muPad) runs quite long and then we see

A similar useless result in MC15 which uses MuPad, too.

The system can be easily solved by hand and we get

Guess MC11 with Maple under the hood for symbolic does not show that problem of not being able to solve this system.

[LucMeekes]

Challenge accepted, Mathcad 11/Maple finds an exact solution:

And if you want the numerical results:

Success!
Luc

[Werner_E]

I didn't doubt that MC11 would be able to solve the system.

The interesting part is that MC15 can do likewise!

Its only until you feed numbers in first place that the system can't be solved:

How does MC11 handle this?

[LucMeekes]

That's in line with my philosophy:

If you want to work symbolically, then use symbols as much as possible. Once you have a symbolic solution you can fill in numbers, to get a numeric answer.

As a matter of fact, I didn't even try to use the numbers with the symbolics, until now:

The error message is "Unknown error"... 😶

Success!
Luc

[StuartBruff]

Did you mean to post this observation here, Werner?   It seems like it should be a thread in its own right ... 🤔

Stuart

[Werner_E]

I came up with this while creating the dummy function for my answer.
But of course you are right thats it off-topic.

EDIT: Now, since the original thread was splitted, its perfectly on-topic 🙂

[StuartBruff]

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@Werner_E wrote:

I came up with this while creating the dummy function for my answer.
But of course you are right thats it off-topic.

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I was trying, unsuccessfully, to hint that it seems sufficiently worthwhile to ask a kindly (or grumpy) Moderator to split it off and delete the extraneous messages (such as mine!).  🙂

Stuart

[Werner_E]

Thats what happens to a thread if the OP doesn't come back in due time 😉

[StuartBruff]

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@Werner_E wrote:

Thats what happens to a thread if the OP doesn't come back in due time 😉

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Yeah, OPs. What are they like?   Always asking questions and then leaving you twiddling your thumbs.   And before you know it something's caught your eye and your mental wheels start leaving neural rubber behind as your brain pulls its handbrake and you enter the Twilight Zone of Thread Drift ... 😁

Still, where would we be without OPs?

Stuart

(Some of my best ideas arise through this mechanism)

[Werner_E]

🙂

You remember the times of the old collab forum and the posting frequency we had ...

[StuartBruff]

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@Werner_E wrote:

🙂

You remember the times of the old collab forum and the posting frequency we had ...

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You must be telepathic.  😱 

When I wrote that, I was actually thinking about the plethora of ideas I got from ... debating ... with a certain Québécois of renown (and permanently persona non grata on these hallowed pages, or so I gather).  His debating style could be - robust - when he locked horns with somebody, but I learned an awful lot from investigating his claims and refuting his arguments against adding features to Mathcad.   😎

It's a shame neither he nor @TomGutman, @RichardJ, and a few other Collabs don't frequent this forum anymore.

Stuart

[RichardJ]

Sorry, but I just don't see any real future for me (or my company) and Mathcad. It was a great product, but PTC wrecked it. Then they went subscription only, and there is no way I will pay a subscription every year to access my own intellectual property. It's a legal form of ransomware. (I do pay such for Solidworks, but there I just have no alternative). I still use Mathcad 15, but I have no access to the later versions of Prime, and therefore no way to really participate in the forums anymore. 

[StuartBruff]

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@RichardJ wrote:

Sorry, but I just don't see any real future for me (or my company) and Mathcad. It was a great product, but PTC wrecked it. Then they went subscription only, and there is no way I will pay a subscription every year to access my own intellectual property. It's a legal form of ransomware. (I do pay such for Solidworks, but there I just have no alternative). I still use Mathcad 15, but I have no access to the later versions of Prime, and therefore no way to really participate in the forums anymore. 

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Hi Richard.

As a home user, Mathcad is just too expensive for what it is for me to subscribe.   I've got both Mathematica and Maple Flow for less than an annual Mathcad subscription and the licences are permanent.

However, I still prefer the Mathcad interface and I quite enjoy getting Express to do useful stuff (and play around with functional programming without having to remember how some Haskell, OCaml, Scala, whatever programming system works).   

Express certainly limits what I can effectively do, but it is possible to solve a lot of problems with it and at least give others some pointers on what to do.

Talking of "play", it would be interesting if PTC followed the pricing strategy of some games.   You can play the basic maths game for free but pay for extra "skills", such as programming or symbolics.  I quite like the MATLAB purchase model: pay £75 for the core MATLAB and the (around) £25 for additional toolboxes. Hmm,  maybe a Mathcad model of paying to upgrade Express to an expandable version, throwing in a few basic, omitted functions (such as Re, Im, and mean), and then adding "skills".  As long it was price competitive, though.

Still, maybe Mathcad Prime 15 will entice us back.  😈

Stuart

[RichardJ]

You can get Smath for free. It's nowhere near as capable as Mathcad, but it can do quite a lot, including unit handling. I don't frequent those forums either, although jmG, and others from the old Collab days, do. I view it as time to move on. The Collab wasn't just about answering basic questions. We had some very interesting discussions, but that does not seem to the case anymore (although, since I rarely visit, I could be wrong about that).  

I have these forums set to ping me if I am mentioned, but not otherwise. 

[StuartBruff]

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@RichardJ wrote:

You can get Smath for free. It's nowhere near as capable as Mathcad, but it can do quite a lot, including unit handling. I don't frequent those forums either, although jmG, and others from the old Collab days, do.  

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I've had a quick look.  Too much to learn (and differences to account for) for me.   I did note jmG's presence, though! 

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The Collab wasn't just about answering basic questions. We had some very interesting discussions, but that does not seem to the case anymore (although, since I rarely visit, I could be wrong about that).  

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That's mostly true.  There are a few good discussions, but it usually involves the usual pre-Prime suspects.  What the Community doesn't seem to be attracting is a critical mass of new blood to infuse it with fresh ideas or opinions.  I don't know why not (I can guess ...).

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I view it as time to move on.

I have these forums set to ping me if I am mentioned, but not otherwise. 

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Eh? What's that? Ping U?  Moving on?

I was rather hoping for ...

😎

Stuart

[Werner_E]

Miss a lot of people from the old collab.

And yes, jmG used to be a very .... special contributor.

AfaIr Tom Gutman left the forum after the migration from the collab to the PTC forum after having massive login problems.
Richard Jackson is around here from time to time but only very sporadic. Guess you can meet him in the SMath forum more often.

All peoples from which I learned at lot in he good old days ... 😞

[prop_design]

I miss the old forum and old mathcad as well. I learned a lot from the files people would post there. I agree with everyone that it's sad PTC destroyed mathcad. The alternatives aren't great. So I'm clinging to the old mathcad as long as it will run. There are a few annoyances but it beats having to switch to something else. That time will come eventually though.

I also refuse to use any software that is subscription based. The fact that people do this is why it's still going on and even growing. It's a terrible idea for the user and great for the company renting the software. I think the people refusing to subscribe are in the minority, unfortunately.