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sjung-21-Visitor
1-Visitor
April 26, 2016
Solved

solving ODE that consists of erfc(x)

  • April 26, 2016
  • 5 replies
  • 2429 views

Dear all,

I'm trying to solve a PDE that consists of erfc(x) and exp(x^2) like the file attached below, which is simply a poisson's equation.

Since it has an unknown boundary condition, F electric field at position x=0, I tried 'minerr(F)' type resolution with F declared beforehand by initial guess.

Unfortunatlely, it keeps saying that F in the 'miners' syntax has not been defined.

Could anyone can help me?

Thank you in advance for your help.

Sung

Best answer by Werner_E

You have a unit problem/inconsistency which makes the odesolve solve block fail, when called. Furthermore you should change the label of F in V(F):=... to "variable".

The meter in constant A should be to the power of 2, not to the power of 5, as they are now. Otherwise you can't add F^2 (under the root).

I am not sure what the error is, you made, but if I boldly add the required units to A

your sheet works OK:

WE

5 replies

W
Werner_E25-Diamond IAnswer
25-Diamond I
April 26, 2016

You have a unit problem/inconsistency which makes the odesolve solve block fail, when called. Furthermore you should change the label of F in V(F):=... to "variable".

The meter in constant A should be to the power of 2, not to the power of 5, as they are now. Otherwise you can't add F^2 (under the root).

I am not sure what the error is, you made, but if I boldly add the required units to A

your sheet works OK:

WE

S
sjung-21-VisitorAuthor
1-Visitor
April 26, 2016

Dear Werner,

It is my pleasure to have you again for this problem. I tried your tip and it works well.

In fact, I forgot to multiply N_{V} to the coefficient A that has a unit of m^{-3}.

Thank you very much for your keen observation.

Sungyeop

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