Merge pull request #77 from nasa/feature/particle_filter_fix

fixing bug: array and keys did not match in particle_filter

Author: teubert

src/progpy/state_estimators/particle_filter.py

@@ -67,9 +67,8 @@ def __init__(self, model, x0, **kwargs):
                 # Added to avoid float/int issues
                 self.parameters['num_particles'] = int(self.parameters['num_particles'])
             sample_gen = x0.sample(self.parameters['num_particles'])
-        samples = [array(sample_gen.key(k), dtype=float64) for k in x0.keys()]
-        
-        self.particles = model.StateContainer(array(samples, dtype=float64))
+        samples = {k: array(sample_gen.key(k), dtype=float64) for k in x0.keys()}
+        self.particles = model.StateContainer(samples)
 
         if 'R' in self.parameters:
             # For backwards compatibility

tests/test_state_estimators.py

@@ -7,7 +7,7 @@
 sys.path.append(join(dirname(__file__), ".."))
 
 from progpy import PrognosticsModel, LinearModel
-from progpy.models import ThrownObject, BatteryElectroChem, PneumaticValveBase
+from progpy.models import ThrownObject, BatteryElectroChem, PneumaticValveBase, BatteryElectroChemEOD
 from progpy.state_estimators import ParticleFilter, KalmanFilter, UnscentedKalmanFilter
 from progpy.uncertain_data import ScalarData, MultivariateNormalDist, UnweightedSamples
 
@@ -561,6 +561,20 @@ def future_loading(t, x=None):
         for t, u, z in zip(times, inputs.data, outputs.data):
             kf.estimate(t, u, z)
 
+    def test_PF_particle_ordering(self):
+        """
+        This is testing for a bug found by @mstraut where particle filter was mixing up the keys if users:
+          1. Do not call m.initialize(), and instead
+          2. provide a state as a dictionary instead of a state container, and
+          3. order the states in a different order than m.states
+        """
+        m = BatteryElectroChemEOD()
+        x0 = m.parameters['x0']  # state as a dictionary with the wrong order
+        filt = ParticleFilter(m, x0, num_particles=2)
+        for key in m.states:
+            self.assertEqual(filt.particles[key][0], x0[key])
+            self.assertEqual(filt.particles[key][1], x0[key])
+
 # This allows the module to be executed directly    
 def main():
      # This ensures that the directory containing StateEstimatorTemplate is in the python search directory