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SH_94160411-Visitor
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November 27, 2020
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Unknown error: "failed"_of_mode_Union

  • November 27, 2020
  • 1 reply
  • 2992 views

Hi!

 

While using Mathcad Prime 6, I encountered a rather strange error. When I try to find solutions to an equation using solve, Mathcad says "Unknown error: "failed"_of_mode_Union". I have done the same procedure a couple times before, and it worked every time. I don't think there's a problem in my code. All the units check out. If anyone could help me solve the problem or recommend a way to get around this method somehow, I would appreciate it very much. I tried solve block, but it only gives one solution and I know there are multiple. I attached the mathcad code.

 

Thank you in advance!

 

Sándor Herőczi

Best answer by Werner_E

Mathcads symbolic is far away from being state of the art and with the introduction of a new symbolic engine in Prime 6 it got even worse.

In Prime 6 you have still the option to switch back to the legacy symbolic engine (Calculation -> Calculation Options -> Legacy-Symbolic-Module).  If you do this and use "simplify", you get a result:

Werner_E_0-1606514135410.png

The error message is because the symbolic result is too large to display. The reason is that the symbolic does not know anything about units and treats N, J, kg, s, m, etc. as unrelated unknown variables. This sure blows up the symbolic result. In the subsequent numeric evaluation of omega, the units cancels and we get a simple result.

 

Primes development goes in glacier speed but if you feel better you may report the error to PTC and hope that it will be fixed. Because in future versions of Prime the old legacy symbolic will not be available anymore.

 

1 reply

W
Werner_E25-Diamond IAnswer
25-Diamond I
November 27, 2020

Mathcads symbolic is far away from being state of the art and with the introduction of a new symbolic engine in Prime 6 it got even worse.

In Prime 6 you have still the option to switch back to the legacy symbolic engine (Calculation -> Calculation Options -> Legacy-Symbolic-Module).  If you do this and use "simplify", you get a result:

Werner_E_0-1606514135410.png

The error message is because the symbolic result is too large to display. The reason is that the symbolic does not know anything about units and treats N, J, kg, s, m, etc. as unrelated unknown variables. This sure blows up the symbolic result. In the subsequent numeric evaluation of omega, the units cancels and we get a simple result.

 

Primes development goes in glacier speed but if you feel better you may report the error to PTC and hope that it will be fixed. Because in future versions of Prime the old legacy symbolic will not be available anymore.

 

    S
    SH_94160411-VisitorAuthor
    1-Visitor
    November 28, 2020

    Thank you so much, it really solved the issue.

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