Implement and add example

cython/gtsam_unstable/examples/FixedLagSmootherExample.py

@@ -0,0 +1,86 @@
+"""
+Demonstration of the fixed-lag smoothers using a planar robot example
+and multiple odometry-like sensors
+Author: Frank Dellaert (C++), Jeremy Aguilon (Python)
+"""
+
+import numpy as np
+
+import gtsam
+import gtsam_unstable
+
+# Create noise models
+PRIOR_NOISE = gtsam.noiseModel_Diagonal.Sigmas(np.array([0.3, 0.3, 0.1]))
+MEASUREMENT_NOISE = gtsam.noiseModel_Diagonal.Sigmas(np.array([0.1, 0.2]))
+
+def _timestamp_key_value(key, value):
+    return gtsam_unstable.FixedLagSmootherKeyTimestampMapValue(
+        key, value
+    )
+
+
+def BatchFixedLagSmootherExample():
+    # Define a batch fixed lag smoother, which uses
+    # Levenberg-Marquardt to perform the nonlinear optimization
+    lag = 2.0
+    smoother_batch = gtsam_unstable.BatchFixedLagSmoother(lag)
+
+
+    # Create containers to store the factors and linearization points
+    # that will be sent to the smoothers
+    new_factors = gtsam.NonlinearFactorGraph()
+    new_values = gtsam.Values()
+    new_timestamps = gtsam_unstable.FixedLagSmootherKeyTimestampMap()
+
+
+    # Create  a prior on the first pose, placing it at the origin
+    prior_mean = gtsam.Pose2(0, 0, 0)
+    X1 = 0
+    new_factors.push_back(gtsam.PriorFactorPose2(X1, prior_mean, PRIOR_NOISE))
+    new_values.insert(X1, prior_mean)
+    new_timestamps.insert(_timestamp_key_value(X1, 0.0))
+
+    delta_time = 0.25
+    time = 0.25
+
+    while time <= 3.0:
+        previous_key = 1000 * (time - delta_time)
+        current_key = 1000 * time
+
+        # assign current key to the current timestamp
+        new_timestamps.insert(_timestamp_key_value(current_key, time))
+
+        # Add a guess for this pose to the new values
+        # Assume that the robot moves at 2 m/s. Position is time[s] * 2[m/s]
+        current_pose = gtsam.Pose2(time * 2, 0, 0)
+        new_values.insert(current_key, current_pose)
+
+        # Add odometry factors from two different sources with different error stats
+        odometry_measurement_1 = gtsam.Pose2(0.61, -0.08, 0.02)
+        odometry_noise_1 = gtsam.noiseModel_Diagonal.Sigmas(np.array([0.1, 0.1, 0.05]))
+        new_factors.push_back(gtsam.BetweenFactorPose2(
+            previous_key, current_key, odometry_measurement_1, odometry_noise_1
+        ))
+
+        odometry_measurement_2 = gtsam.Pose2(0.47, 0.03, 0.01)
+        odometry_noise_2 = gtsam.noiseModel_Diagonal.Sigmas(np.array([0.05, 0.05, 0.05]))
+        new_factors.push_back(gtsam.BetweenFactorPose2(
+            previous_key, current_key, odometry_measurement_2, odometry_noise_2
+        ))
+
+        # Update the smoothers with the new factors
+        smoother_batch.update(new_factors, new_values, new_timestamps)
+
+        print("Timestamp = " + str(time) + ", Key = " + str(current_key))
+        print(smoother_batch.calculateEstimatePose2(current_key))
+
+        new_timestamps.clear()
+        new_values.clear()
+        new_factors.resize(0)
+
+
+        time += delta_time
+
+if __name__ == '__main__':
+    BatchFixedLagSmootherExample()
+    print("Example complete")

gtsam_unstable/gtsam_unstable.h

@@ -505,15 +505,9 @@ virtual class DiscreteEulerPoincareHelicopter : gtsam::NoiseModelFactor {
 //*************************************************************************
 // nonlinear
 //*************************************************************************
-#include <gtsam_unstable/nonlinear/sequentialSummarization.h>
-gtsam::GaussianFactorGraph* summarizeGraphSequential(
-    const gtsam::GaussianFactorGraph& full_graph, const gtsam::KeyVector& indices);
-gtsam::GaussianFactorGraph* summarizeGraphSequential(
-    const gtsam::GaussianFactorGraph& full_graph, const gtsam::Ordering& ordering, const gtsam::KeySet& saved_keys);
-
 #include <gtsam_unstable/nonlinear/FixedLagSmoother.h>
 class FixedLagSmootherKeyTimestampMapValue {
-  FixedLagSmootherKeyTimestampMapValue(const gtsam::Key& key, double timestamp);
+  FixedLagSmootherKeyTimestampMapValue(size_t key, double timestamp);
   FixedLagSmootherKeyTimestampMapValue(const gtsam::FixedLagSmootherKeyTimestampMapValue& other);
 };
 
@@ -528,7 +522,7 @@ class FixedLagSmootherKeyTimestampMap {
   bool empty() const;
   void clear();
 
-  double at(const gtsam::Key& key) const;
+  double at(const size_t key) const;
   void insert(const gtsam::FixedLagSmootherKeyTimestampMapValue& value);
 };
 
@@ -558,6 +552,10 @@ virtual class BatchFixedLagSmoother : gtsam::FixedLagSmoother {
   BatchFixedLagSmoother(double smootherLag, const gtsam::LevenbergMarquardtParams& params);
 
   gtsam::LevenbergMarquardtParams params() const;
+  template <VALUE = {gtsam::Point2, gtsam::Rot2, gtsam::Pose2, gtsam::Point3,
+                     gtsam::Rot3, gtsam::Pose3, gtsam::Cal3_S2, gtsam::Cal3DS2,
+                     Vector, Matrix}>
+  VALUE calculateEstimate(size_t key) const;
 };
 
 #include <gtsam_unstable/nonlinear/IncrementalFixedLagSmoother.h>