The default behavior for adding and solving with noisemodels has changed from Pastas 1.5. Find more information here


Model.solve(tmin=None, tmax=None, freq=None, warmup=None, noise=None, solver=None, report=True, initial=True, weights=None, fit_constant=True, freq_obs=None, **kwargs)[source]#

Method to solve the time series model.

  • tmin (str, optional) – String with a start date for the simulation period (E.g. ‘1980’). If none is provided, the tmin from the oseries is used.

  • tmax (str, optional) – String with an end date for the simulation period (E.g. ‘2010’). If none is provided, the tmax from the oseries is used.

  • freq (str, optional) – String with the frequency the stressmodels are simulated. Must be one of the following (D, h, m, s, ms, us, ns) or a multiple of that e.g. “7D”.

  • warmup (float, optional) – Warmup period (in Days) for which the simulation is calculated, but not used for the calibration period.

  • noise (bool, optional) – This argument is deprecated and will be removed in Pastas version 2.0.0. To solve using a noisemodel (i.e. noise=True), add a noisemodel to the model using ml.add_noisemodel(n), where n is an instance of a noisemodel (e.g., n = ps.ArNoiseModel()). To solve without a noisemodel (noise=False), remove the noisemodel first (if present) using ml.del_noisemodel().

  • solver (Class pastas.solver.Solver, optional) – Instance of a pastas Solver class used to solve the model. Options are: ps.LeastSquares() (default) or ps.LmfitSolve(). An instance is needed as of Pastas 0.23, not a class!

  • report (bool, optional) – Print a report to the screen after optimization finished. This can also be manually triggered after optimization by calling print(ml.fit_report( )) on the Pastas model instance.

  • initial (bool, optional) – Reset initial parameters from the individual stress models. Default is True. If False, the optimal values from an earlier optimization are used.

  • weights (pandas.Series, optional) – Pandas Series with values by which the residuals are multiplied, index-based. Must have the same indices as the oseries.

  • fit_constant (bool, optional) – Argument that determines if the constant is fitted as a parameter. If it is set to False, the constant is set equal to the mean of the residuals.

  • freq_obs (str, optional) – String with the frequency of the observations that the model will be calibrated on. Must be one of the following (D, h, m, s, ms, us, ns) or a multiple of that e.g. “7D”. Should generally be larger than the frequency of the original observations and the model frequency (freq). If freq_obs is not set, the frequency of the model (freq) will be used.

  • **kwargs (dict, optional) – All keyword arguments will be passed onto minimization method from the solver. It depends on the solver used which arguments can be used.

Return type



  • The solver instance including some results are stored as ml.solver. From here one can access the covariance (ml.solver.pcov) and correlation matrix ( ml.solver.pcor).

  • Each solver returns a number of results after optimization. These solver specific results are stored in ml.solver.result and can be accessed from there.

See also


Different solver objects are available to estimate parameters.