Imposing conservation laws in ode systems using ode solvers

How can I impose conservation laws when using matlab ode solvers? I have an ode system with 12 variables, 8 differential equations (for 8 of the variables) and 4 conservation laws

Answer 1

[Torsten]

Usually, the conservation principles are already part of the differential equations.

Could you be more specific of what you exactly mean ?

Best wishes

Torsten.