# yade-users team mailing list archive

## Re: The convergence criterion in YADE

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I must correct my previous definition of CC.

It is better to define :

sum(|SFi|)  (sum of the norms of resutant forces on bodies)
CC =    ___________
**sum(|Fi|)**    (sum of the norms of contact forces)

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In my previous definition, CC was proportional to the number of bodies because the denominator was mean(|Fi|).
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Sorry...

Bruno

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Simply compute the sum of all forces on a body. At equilibrium, sum of all Fi on body Bk is 0. If you sum now on all bodies, you still have sum of F over all i and k equal to 0 (SFik = 0).
```If SFik != 0, you are not at equilibrium.
If you normalize SFik dividing it by the mean value of F, you have the classical definition of CC.

Bruno

_______________
Chareyre Bruno
Maître de conférence
Institut National Polytechnique de Grenoble
Tél : 04.56.52.86.21
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________________________________________ bureau I 08 Laboratoire 3S (Soils Solids Structures) BP 53 - 38041, Grenoble cedex 9 - France _______________
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_______________
Chareyre Bruno
Maître de conférence
Institut National Polytechnique de Grenoble
Tél : 04.56.52.86.21
```
________________________________________ bureau I 08 Laboratoire 3S (Soils Solids Structures) BP 53 - 38041, Grenoble cedex 9 - France _______________
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