Prime 2.0 Odesolve issue

[Raiko]

Hello folks,

I tried the Prime 2 sheet labelled "free-fall.xmcd" in order to familiarize myself with the ODE.

I ran into a problem when changing the guess value's unit from imperial (ft) to metric (m). Prime doesn't compute telling me that the units are not compatible (see attached worksheet).

Until now I supposed this to be the raison d'etre of MathCad that it converts units automatically. Am I missing here something?

Raiko

P.S.

Changing all guess value's units to metric didn't help either.

[Werner_E · Accepted solution]

In the solve block change the label(Stil) of the "m" in "120000 m" from "none" to "Unit" and it works. If set to none its obviously interpreted as variable m which has the unit kg.

[Raiko]

Thanks Werner. I didn't expect it to be so easy.

Raiko

[AlanStevens]

Raiko Milanovic wrote:

Hello folks,

Am I missing here something?

Within the solve block, in the first line, select the 'm' and,using the Labels tab, change this to units. Currently Prime thinks this is the mass 'm' you defined earlier.

Alan

[AndyWesterman]

Hi Raiko,

I think that you are experiencing one of Prime's little issues: You can define the same name as unit , variable, constant etc.

Changing the label from 120000m to 120000m (unit) seems to allow the odesolve to run.

Whether there are any other instances where you need to change the "label" I don't know - Good luck.

Hope this helps

Andy

[tdevaraj]

Hi Raiko,

Seems its an issue with the labels on the guess value not being assigned.

Apply the label as unit for each guess value and it should all work fine.

Regards,

Thomas

[Werner_E]

Wow! Thats the nice thing about moderated discussions. You get a variety of homonymous answers among which you can choose 😉

I hope that this nightmare is over soon.