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electrostatic - electric field gradient
Posted Sep 29, 2010, 10:39 p.m. EDT 3 Replies
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Hi, I'm widya
I would like to ask about the electric field gradient, I'm using version 3.3, does anyone know how to write ?|E|^2 into expression?
I would like to ask about the electric field gradient, I'm using version 3.3, does anyone know how to write ?|E|^2 into expression?
3 Replies Last Post Sep 30, 2010, 8:26 a.m. EDT
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Posted:
1 decade ago
Hi
I do not have 3.3, but if I apply "similarity", and make the hypothesis that:
_E_ = (Ex,Ey,Ez)
then the norm should be something like
norm(_E_) = (_E_*_E_) = Ex^2+Ey^2+Ez^2
provided _E_ is real this is certainly true.
If _E_ is imaginary, I'm no longer sure now if you can use directly the same formula or you should use the complex conjugated version, I would have to check again ;)
It's mentionned somewhere in the doc
if you want the norm of the gradient of _E_, at least in V3.5 and V4, you have the components of the gradient defined as (Exx,Eyy,Ezz) or Exx = d(Ex,x)
so this should then be trivial to extrapolate, with the little warning to check for complex values.
If Exx is not defined in 3.3, you still have the diff(Ex,x), or is it already the new current notation d(Ex,x) that applies in 3.3 ?
--
Good luck
Ivar
I do not have 3.3, but if I apply "similarity", and make the hypothesis that:
_E_ = (Ex,Ey,Ez)
then the norm should be something like
norm(_E_) = (_E_*_E_) = Ex^2+Ey^2+Ez^2
provided _E_ is real this is certainly true.
If _E_ is imaginary, I'm no longer sure now if you can use directly the same formula or you should use the complex conjugated version, I would have to check again ;)
It's mentionned somewhere in the doc
if you want the norm of the gradient of _E_, at least in V3.5 and V4, you have the components of the gradient defined as (Exx,Eyy,Ezz) or Exx = d(Ex,x)
so this should then be trivial to extrapolate, with the little warning to check for complex values.
If Exx is not defined in 3.3, you still have the diff(Ex,x), or is it already the new current notation d(Ex,x) that applies in 3.3 ?
--
Good luck
Ivar
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Posted:
1 decade ago
I've tried diff(Ex,x) and that work. thank you Ivar.
but then I encontered another error messege which was,
error : 7043
Initial guess leads to undefined function value.
how can I solve this kind off error messege?
but then I encontered another error messege which was,
error : 7043
Initial guess leads to undefined function value.
how can I solve this kind off error messege?
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Posted:
1 decade ago
Hi
check what are the initial conditions (often = 0), and sometimes you divide by this value => error. It could also come from an imaginary part when only real is expected, then a "real() would help. Normally you should have a way to test your mdoel only on the initial conditions (even in 3.3)
--
Good luck
Ivar
check what are the initial conditions (often = 0), and sometimes you divide by this value => error. It could also come from an imaginary part when only real is expected, then a "real() would help. Normally you should have a way to test your mdoel only on the initial conditions (even in 3.3)
--
Good luck
Ivar