Unable to avoid copy while creating an array as requested #326

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1. Meikul commented on Jun 28, 2026

   

   Meikul

   on Jun 28, 2026

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   I'm also running into this issue in chapter 5 unfortunately. I installed the project dependencies via the conda environment.yml file. and I've tried changing the versions of some packages, but I've had no luck.
2. jclsn commented on Jun 29, 2026

   

   jclsn

   on Jun 29, 2026

   Last edited by jclsn

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   @Meikul: I patched the mahalanobis and likelihood functions by replacing them with this

    def _safe_mahalanobis(self):
        if self._mahalanobis is None:
            y = np.atleast_2d(self.y)
            if y.shape[0] == 1:
                y = y.T
            SI = np.atleast_2d(self.SI)
            self._mahalanobis = np.sqrt((y.T @ SI @ y).item())
        return self._mahalanobis
    
    def _safe_likelihood(self):
        if self._likelihood is None:
            self._likelihood = exp(self.log_likelihood)
            if self._likelihood == 0:
                self._likelihood = sys.float_info.min
        return self._likelihood

   Haven't had any issues since. Since I built myself a JupyterLab Docker container with the book baked in, I used a sitecustomize.py

   # sitecustomize.py
   import numpy as np
   import sys
   import warnings
   
   from math import exp
   from filterpy.kalman import KalmanFilter
   
   warnings.filterwarnings(
       "ignore",
       category=SyntaxWarning,
       message=r".*invalid escape sequence.*"
   )
   
   def _safe_mahalanobis(self):
       if self._mahalanobis is None:
           y = np.atleast_2d(self.y)
           if y.shape[0] == 1:
               y = y.T
           SI = np.atleast_2d(self.SI)
           self._mahalanobis = np.sqrt((y.T @ SI @ y).it
       return self._mahalanobis
   
   def _safe_likelihood(self):
       if self._likelihood is None:
           self._likelihood = exp(self.log_likelihood)
           if self._likelihood == 0:
               self._likelihood = sys.float_info.min
       return self._likelihood
   
   KalmanFilter.mahalanobis = property(_safe_mahalanobis
   KalmanFilter.likelihood = property(_safe_likelihood) 

   Which I put into /opt/conda/lib/python3.1/site-packages/. This is probably the easiest approach for you as well. You should probably put it into ~/.local/lib/python3.x depending on your setup though.

   Unfortunately @rlabbe is not really responding anymore, so I didn't bother to send a PR.