gEconpy.model.perturbation.check_bk_condition_pt#
- gEconpy.model.perturbation.check_bk_condition_pt(A, B, C, D, tol=1e-08)#
Check the Blanchard-Kahn condition for a model.
Compute the generalized eigenvalues of system in the form presented in [1]. Per [2], the number of unstable eigenvalues (\(|v| > 1\)) should not be greater than the number of forward-looking variables. Failing this test suggests timing problems in the definition of the model.
- Parameters:
- A: TensorVariable
Jacobian matrix of the DSGE system, evaluated at the steady state, taken with respect to past variables values that are known when decision-making: those with t-1 subscripts.
- B: TensorVariable
Jacobian matrix of the DSGE system, evaluated at the steady state, taken with respect to variables that are observed when decision-making: those with t subscripts.
- C: TensorVariable
Jacobian matrix of the DSGE system, evaluated at the steady state, taken with respect to variables that enter in expectation when decision-making: those with t+1 subscripts.
- D: TensorVariable
Jacobian matrix of the DSGE system, evaluated at the steady state, taken with respect to exogenous shocks.
- tol: float, optional
Tolerance below which numerical values are considered zero. Default is 1e-8.
- Returns: