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J
JohnArcher10-Marble
10-Marble
April 22, 2022
Solved

Mathcad 15M050 and Prime8: Series solutions differences.

  • April 22, 2022
  • 3 replies
  • 8874 views

Each package gives quite different "simplifications" to a complex variable quotient. Old Mathcad defaults to a sixth order Series but Prime8 produces a shorter result that is quite different from that of 15M050.

The error seems to be a function of the quotient complexity. 

I am careful to run both packages side by side on a new HP Envy laptop as I try to transition to Prime8 while writing a patent disclosure. 

This error makes Prime8 unusable for what I do.

Has anyone else seen this?

Best answer by Werner_E
@JohnArcher wrote:

I have tried everything. A simple Prime8 work file gets a "file type error"".

 

I am sorry to hear that. I am pretty sure that we already had seen Prime 8 files as attachments here in the forum, so it definitely should work.
Maybe a forum admin can look into this and help you attaching the file.  @unknown 

3 replies

W
Werner_E25-Diamond I
25-Diamond I
April 23, 2022

Its absolutely unclear to me which "difference" you are referring to as you don't show any examples.

Best guess is that you are talking about symbolic evaluation.
Prime starting from version 6 uses a different symbolic engine (a free one as opposed to the older muPad which PZC had to licence from Mathworks). I understand that the new engine is less powerful but is a work in progress as PTC tries to develop it, fix errors and maybe even add new tricks.

Control over the output of a symbolic evaluation never was easy in Mathcad and the possibilities are quite limited.

If you post examples of your expression and make clear, which kind of result you need, someone may be able to achieve better results as with a simple "simplify".

    R
    rgunwaldsen15-Moonstone
    15-Moonstone
    April 23, 2022

    Hard to evaluate since you do not provide examples.

    I encountered a problem some years ago with new symbolic engine in Prime 6 which envolved a complex transfer function and the functions numer() and denom(). The new engine "helpfully" simplified the original transfer function before applying numer() or denom() (see attached P6 worksheet).

    Perhaps your problem has similar root cause?

      J
      JohnArcher10-MarbleAuthor
      10-Marble
      April 23, 2022

      Thanks to all for replying. Prime8 tries to make Keywords more useful: at first it was irritating!

      I am 86, born in London and I remember the V1 and V2 rockets. I started with Mathcad 4 on a 5.25inch floppy disc while at Purdue.

      My retirement fun job was EMC in the JSF Program Office.

      I am simply solving:  H(s) = P(s) / Q(s) followed by rationalization, partial fractions and InvLaplace.

      Old Mathcad defaults to a sensible 6th order solution for numerator and denominator which you can reduce if 

      the partial fractions generate right half plane poles and you know that this cannot be.

      Prime8 generates RHP poles if I use a Series greater than 3 and the numbers are wrong. Ohms law sets these limits.

      I have played with Labelling and kept things very simple as I try to produce a patent submission in Prime8 dealing with arc fault suppression.

      So far, I have generated four PTC Case files. Maybe I have messed up. 

      I will have a 7.30pm Email and phone meeting with my PTC contact on Monday, April25 to discuss and learn.

      W
      Werner_E25-Diamond I
      25-Diamond I
      April 23, 2022

      Still unclear. Why don't you post some examples? Screenshots and preferably the Prime sheet as attachment.

      J
      JohnArcher10-MarbleAuthor
      10-Marble
      April 25, 2022

      I have tried drag and browse but I get "wrong file type" message when .xmcd is used.

      W
      Werner_E25-Diamond I
      25-Diamond I
      April 25, 2022
      @JohnArcher wrote:

      I have tried drag and browse but I get "wrong file type" message when .xmcd is used.

      I just edited my reply above  moments before you posted this message 😉

      Unfortunately this forum only allows a handful of file types as attachments and "xps" is not amongst them (it sure should be!).
      If you really can't supply a small Prime sheet demonstrating the problems you will have to put the xps-file into an archive like "zip" and attach the archive.

       

      J
      JohnArcher10-MarbleAuthor
      10-Marble
      April 25, 2022

      Hi, Werner. My e mail address is John.R.Archer@hotmail.com

      I can attach a small Prime8 file in response. I have no idea how to attach a Worksheet to the Tips forum.

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