VectorEvaluationFactor

Overview¶

VectorEvaluationFactor is a unary factor for vector-valued measurements evaluated from a basis parameter matrix. It enforces $\mathbf{f}(x)$ to match a measurement vector at a given point.

Authors: Frank Dellaert, et al. (see THANKS for the full author list)

See LICENSE for the license information

# Install GTSAM from pip if running in Google Colab
try:
    import google.colab
    %pip install --quiet gtsam-develop
except ImportError:
    pass  # Not in Colab

Key Functionality / API¶

VectorEvaluationFactor(key, z, model, M, N, x) constrains the full vector.
Optional interval parameters a, b scale the basis domain.

C++ Usage Example¶

gtsam::Vector z{{1.0, 0.0, -0.5}};
auto model = gtsam::noiseModel::Isotropic::Sigma(3, 0.1);
size_t M = 3, N = 6;
double x = 0.0;
gtsam::VectorEvaluationFactor<gtsam::Chebyshev2> factor(key, z, model, M, N, x);

Python Example¶

import numpy as np
import gtsam

candidates = [n for n in dir(gtsam) if n.startswith("VectorEvaluationFactor")]
print("VectorEvaluationFactor wrappers:")
for name in candidates:
    print("  ", name)

cls = None
selected = None
for name in [
    "VectorEvaluationFactorChebyshev2",
    "VectorEvaluationFactorChebyshev2Basis",
    "VectorEvaluationFactorChebyshev1Basis",
    "VectorEvaluationFactorFourierBasis",
]:
    if hasattr(gtsam, name):
        cls = getattr(gtsam, name)
        selected = name

    if cls is None:
        print("No VectorEvaluationFactor wrapper found; skipping execution.")
    else:
        z = np.array([1.0, 0.0, -0.5])
        model = gtsam.noiseModel.Isotropic.Sigma(3, 0.1)
        key = gtsam.symbol('c', 0)
        factor = cls(key, z, model, 3, 6, 0.0)
        print(f"Created {selected} with dim {factor.dim()}")

VectorEvaluationFactor wrappers:
   VectorEvaluationFactorChebyshev1Basis
   VectorEvaluationFactorChebyshev2
   VectorEvaluationFactorChebyshev2Basis
   VectorEvaluationFactorFourierBasis
Created VectorEvaluationFactorChebyshev2 with dim 3
Created VectorEvaluationFactorChebyshev2Basis with dim 3
Created VectorEvaluationFactorChebyshev1Basis with dim 3
Created VectorEvaluationFactorFourierBasis with dim 3

Source¶

BasisFactors.h