smape1¶
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HydroErr.HydroErr.
smape1
(simulated_array, observed_array, replace_nan=None, replace_inf=None, remove_neg=False, remove_zero=False)¶ Compute the the Symmetric Mean Absolute Percentage Error (1) (SMAPE1).
Range: 0 ≤ SMAPE1 < 100%, smaller is better, symmetrical.
Notes: This metric is an adjusted version of the MAPE.
Parameters: - simulated_array (one dimensional ndarray) – An array of simulated data from the time series.
- observed_array (one dimensional ndarray) – An array of observed data from the time series.
- replace_nan (float, optional) – If given, indicates which value to replace NaN values with in the two arrays. If None, when a NaN value is found at the i-th position in the observed OR simulated array, the i-th value of the observed and simulated array are removed before the computation.
- replace_inf (float, optional) – If given, indicates which value to replace Inf values with in the two arrays. If None, when an inf value is found at the i-th position in the observed OR simulated array, the i-th value of the observed and simulated array are removed before the computation.
- remove_neg (boolean, optional) – If True, when a negative value is found at the i-th position in the observed OR simulated array, the i-th value of the observed AND simulated array are removed before the computation.
- remove_zero (boolean, optional) – If true, when a zero value is found at the i-th position in the observed OR simulated array, the i-th value of the observed AND simulated array are removed before the computation.
Returns: The symmetric mean absolute percentage error (1).
Return type: Examples
Note that if we switch the simulated and observed arrays the result is the same
>>> import HydroErr as he >>> import numpy as np
>>> sim = np.array([5, 7, 9, 2, 4.5, 6.7]) >>> obs = np.array([4.7, 6, 10, 2.5, 4, 7]) >>> he.smape1(sim, obs) 5.871915694397428 >>> he.smape1(obs, sim) 5.871915694397428
References
- Flores, B.E., 1986. A pragmatic view of accuracy measurement in forecasting. Omega 14(2) 93-98.
- Goodwin, P., Lawton, R., 1999. On the asymmetry of the symmetric MAPE. International Journal of Forecasting 15(4) 405-408.