# Get information about the solution

Hello,
In the Hyperelasticity example of the doc.

How can I get the final value of the potential energie Pi? (ie evaluate Pi on the mesh+vector u solution)
thanks

You can evaluate scalar-valued integrals using the `assemble` function. To get the final value of `Pi`, you would call `assemble(Pi)` after the `solve`, which will return the value of the integral as a Python `float`. To get just the elastic potential energy, you would use `assemble(psi*dx)`, and so on.

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