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24-Ruby IV
ValeryOchkov24-Ruby IV
24-Ruby IV
May 19, 2018
Solved

Error by ode solution

  • May 19, 2018
  • 3 replies
  • 6460 views

Why I have an error by ode solution?

Same ode in Prime has no error!

See please Mathcad 15 sheet in attach!

Best answer by Werner_E

> Help please!

I can't as a I am not real sure If MC should solve this system - its not a normal system of ODEs anyway.

My question was what you changed in the converted file in Prime to make it work.

.) Prime should work with your dummy units, too.

.) Prime should work with the derivative operator, too (it should not be necessary to use the prime symbol '')

.) Prime should work without providing the number of steps.

The above three were the only changes I was able to spot. But you should know exactly what you changed in the converted sheet. Was there anything else  you changed?

3 replies

W
Werner_E25-Diamond I
25-Diamond I
May 20, 2018

When I convert your worksheet to Prime I get an error, too.

As usual in Prime its an "unknown error: ode%

V
24-Ruby IV
ValeryOchkov24-Ruby IVAuthor
24-Ruby IV
May 20, 2018

Thanks, Werner for the attention on the problem.

I have converted the file and a little edit it. See please the picture and the Prime 4 in attach.

tulip.png 

V
24-Ruby IV
ValeryOchkov24-Ruby IVAuthor
24-Ruby IV
May 20, 2018

One simple example:

e.png

W
Werner_E25-Diamond I
25-Diamond I
May 20, 2018

Ah! A simpler example always is better! Even though the pictures are far too large, again!

So you should not only edit the converted Prime sheet to get the correct syntax for Prime's "odesolve" but also edit the Mathcad 15 sheet to get the correct MC15 syntax (the function name y is not used as argument of odesolve in real Mathcad) 😉

B.png

Unfortunately this simple example does not relate to your original file where it seems that you used the correct syntax. What did you change in Prime there to make it work (I am sure too lazy to compare myself). Did you change something else other than using real units, writing the derivatives using the prime symbols and adding the number of steps?

W
Werner_E25-Diamond I
25-Diamond I
May 20, 2018

*** DELETE ***

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-MFra-21-Topaz II
21-Topaz II
May 20, 2018

Hi,

The system consists of four differential equations and six unknown functions. F1 and F2 are indefinite. Gravity acceleration was not dimensionless. Furthermore the conditions

adjoint.jpg

should be respected.

V
24-Ruby IV
ValeryOchkov24-Ruby IVAuthor
24-Ruby IV
May 20, 2018
@-MFra- wrote:

Hi,

The system consists of four differential equations and six unknown functions. F1 and F2 are indefinite. Gravity acceleration was not dimensionless. Furthermore the conditions

adjoint.jpg

should be respected.

Sorry, no problem in Prime. See please one fine solution

No-tulip.png

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAuthor
    24-Ruby IV
    May 21, 2018

    Mathcad Prime has new solver.

    I think Mathcad 15 solver has an error and cannot solve my problem. Prime can. And with units! Or some others?

    But Mathcad 15 can solve more powerful problem - see please the attach/ Strange!

     

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