VectorComponentFactor

Overview¶

VectorComponentFactor is a unary factor that constrains a single component of a vector-valued basis function at a given point. It is useful when only one component is observed.

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¶

VectorComponentFactor(key, z, model, P, N, i, x) constrains component i.
Optional interval parameters a, b scale the basis domain.

C++ Usage Example¶

auto model = gtsam::noiseModel::Isotropic::Sigma(1, 0.1);
size_t P = 3, N = 6, i = 1;
double x = 0.5;
double z = -0.2;
gtsam::VectorComponentFactor<gtsam::Chebyshev2> factor(key, z, model, P, N, i, x);

Python Example¶

import gtsam

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

cls = None
selected = None
for name in candidates:
    if hasattr(gtsam, name):
        cls = getattr(gtsam, name)
        selected = name

    if cls is None:
        print("No VectorComponentFactor wrapper found; skipping execution.")
    else:
        model = gtsam.noiseModel.Isotropic.Sigma(1, 0.1)
        key = gtsam.symbol('c', 0)
        factor = cls(key, -0.2, model, 3, 6, 1, 0.5)
        print(f"Created {selected} with dim {factor.dim()}")

VectorComponentFactor wrappers:
   VectorComponentFactorChebyshev1Basis
   VectorComponentFactorChebyshev2
   VectorComponentFactorChebyshev2Basis
   VectorComponentFactorFourierBasis
Created VectorComponentFactorChebyshev1Basis with dim 1
Created VectorComponentFactorChebyshev2 with dim 1
Created VectorComponentFactorChebyshev2Basis with dim 1
Created VectorComponentFactorFourierBasis with dim 1

Source¶

BasisFactors.h