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ptc-31073561-Visitor
1-Visitor
May 29, 2013
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Odesolver

  • May 29, 2013
  • 1 reply
  • 2779 views

Hello,

This is my first post. I have been trying to get the ODESOLVER to work in the PRIME 2.0. It took me awhile to get even the help examples to work. I think I figured out that you have to use the ctrl+= when you set the constraints like in MATHCAD 15, but the help files do not tell you that. I figured that out by watching some u-tube videos.

In any case, I am trying to solve a simple ODE to plot the displacement of a particle given a velocity function. The application is applying ocean wave theory.

Any help would be appreciated, I have spent too much time trying to figure out this simple problem so I can then add other velocity compents to get my final answer.

My file is attached.

Thanks.

John T.

Best answer by Werner_E

Basically you had too much initial condition - for a DE of first order you can have only one IC, not two!

Funny that Prime's error message is telling the exact opposite, it say that you have too few ICs.

See attached

1 reply

W
Werner_E25-Diamond IAnswer
25-Diamond I
May 29, 2013

Basically you had too much initial condition - for a DE of first order you can have only one IC, not two!

Funny that Prime's error message is telling the exact opposite, it say that you have too few ICs.

See attached

P
ptc-31073561-VisitorAuthor
1-Visitor
May 29, 2013

Werner,

Thanks so much. Thanks makes total sense and I could not figure out what other equations it wanted.

So to confirm you do have to use the CTR+= in the constraints, it works but just want to make sure....the documentation is poor.

John

W
Werner_E25-Diamond I
25-Diamond I
May 29, 2013
So to confirm you do have to use the CTR+= in the constraints, it works but just want to make sure....the documentation is poor.

I guess the doc in Mathcad 15 is better, as is the whole program. Unfortunately Prime is the future and as its still unfinished and a work in progress (never understood why they call it version 2.0 instead of 0.2) we can only hope it will get better.

And, yes, you have to use the boolean equal sign for initial conditions and constraints.

Mathcad has a lot of different equal signs, for assignments (:=), numeric evaluation (=), boolean conditions /the "fat" =), symbolic evaluation (-->), local assignments in programs (<--) and in MC15 another one for global assignments. But this makes sense.

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