Third order derivative for external functions

Stochastic simulations
1

Hi,

I want to use an external function in my model block, and I want to use third order perturbation. I declare the function using:
external_function(name = funcname, nargs = 3, first_deriv_provided, second_deriv_provided);

It works fine with order=2, but when I use order=3, I get the error:
ERROR: third order derivatives of external functions are not implemented

Is there a way that I can implement the third order derivative of the external function?

Thank you,
Ghazika1

2

Unfortunately, not yet: github.com/DynareTeam/dynare/issues/300

3

Thank you jpfeifer.

4

Does it mean that I can not use Ramsey policy with external function in constraint?

5

Yes, you can, but you will be restricted in the feasible order

6

But I receive the same error:
Ramsey Problem: added 16 Multipliers.
Found 16 equation(s).
Found 33 FOC equation(s) for Ramsey Problem.
Evaluating expressions…done
Computing static model derivatives:

  • order 1
    Computing dynamic model derivatives:
  • order 1
  • order 2
    ERROR: third order derivatives of external functions are not implemented

Error using dynare (line 229)
DYNARE: preprocessing failed

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How can I fix it? if I set policy, the model works. Or do you have any example for Ramsey policy with external functions, please?

8

Could you please provide me with the files?