# [MBDyn-users] About the definition of the Jacobian matrix during the initial assembly phase

masarati at aero.polimi.it masarati at aero.polimi.it
Tue Apr 3 22:54:31 CEST 2012

> Dear Mr. Masarati,
>
> Let us assume the contribution of an element to the residual in
> InitialAssRes would be:
>
> Res = f(x)
>
> Is it correct, that the contribution to the Jacobian matrix in
> InitialAssJac is:
>
> Jac = -\frac{\partial f(x)}{\partial x}

Correct.  Cheers, p.