kill logNormalizationConstant in favor of negLogConstant

gtsam/discrete/discrete.i

@@ -113,7 +113,6 @@ virtual class DiscreteConditional : gtsam::DecisionTreeFactor {
 
   // Standard interface
   double negLogConstant() const;
-  double logNormalizationConstant() const;
   double logProbability(const gtsam::DiscreteValues& values) const;
   double evaluate(const gtsam::DiscreteValues& values) const;
   double error(const gtsam::DiscreteValues& values) const;

gtsam/hybrid/HybridGaussianConditional.cpp

@@ -155,7 +155,7 @@ void HybridGaussianConditional::print(const std::string &s,
     std::cout << "(" << formatter(dk.first) << ", " << dk.second << "), ";
   }
   std::cout << std::endl
-            << " logNormalizationConstant: " << logNormalizationConstant()
+            << " logNormalizationConstant: " << -negLogConstant()
             << std::endl
             << std::endl;
   conditionals_.print(

gtsam/hybrid/hybrid.i

@@ -62,7 +62,6 @@ virtual class HybridConditional {
 
   // Standard interface:
   double negLogConstant() const;
-  double logNormalizationConstant() const;
   double logProbability(const gtsam::HybridValues& values) const;
   double evaluate(const gtsam::HybridValues& values) const;
   double operator()(const gtsam::HybridValues& values) const;

gtsam/hybrid/tests/testHybridGaussianConditional.cpp

@@ -61,11 +61,11 @@ const HybridGaussianConditional hybrid_conditional({Z(0)}, {X(0)}, mode,
 TEST(HybridGaussianConditional, Invariants) {
   using namespace equal_constants;
 
-  // Check that the conditional normalization constant is the max of all
-  // constants which are all equal, in this case, hence:
-  const double K = hybrid_conditional.logNormalizationConstant();
-  EXPECT_DOUBLES_EQUAL(K, conditionals[0]->logNormalizationConstant(), 1e-8);
-  EXPECT_DOUBLES_EQUAL(K, conditionals[1]->logNormalizationConstant(), 1e-8);
+  // Check that the conditional (negative log) normalization constant is the min
+  // of all constants which are all equal, in this case, hence:
+  const double K = hybrid_conditional.negLogConstant();
+  EXPECT_DOUBLES_EQUAL(K, conditionals[0]->negLogConstant(), 1e-8);
+  EXPECT_DOUBLES_EQUAL(K, conditionals[1]->negLogConstant(), 1e-8);
 
   EXPECT(HybridGaussianConditional::CheckInvariants(hybrid_conditional, hv0));
   EXPECT(HybridGaussianConditional::CheckInvariants(hybrid_conditional, hv1));
@@ -231,8 +231,8 @@ TEST(HybridGaussianConditional, Likelihood2) {
     CHECK(jf1->rows() == 2);
 
     // Check that the constant C1 is properly encoded in the JacobianFactor.
-    const double C1 = hybrid_conditional.logNormalizationConstant() -
-                      conditionals[1]->logNormalizationConstant();
+    const double C1 =
+        conditionals[1]->negLogConstant() - hybrid_conditional.negLogConstant();
     const double c1 = std::sqrt(2.0 * C1);
     Vector expected_unwhitened(2);
     expected_unwhitened << 4.9 - 5.0, -c1;

gtsam/inference/Conditional-inst.h

@@ -59,23 +59,14 @@ double Conditional<FACTOR, DERIVEDCONDITIONAL>::evaluate(
 
 /* ************************************************************************* */
 template <class FACTOR, class DERIVEDCONDITIONAL>
-double Conditional<FACTOR, DERIVEDCONDITIONAL>::negLogConstant()
-    const {
-  throw std::runtime_error(
-      "Conditional::negLogConstant is not implemented");
-}
-
-/* ************************************************************************* */
-template <class FACTOR, class DERIVEDCONDITIONAL>
-double Conditional<FACTOR, DERIVEDCONDITIONAL>::logNormalizationConstant()
-    const {
-  return -negLogConstant();
+double Conditional<FACTOR, DERIVEDCONDITIONAL>::negLogConstant() const {
+  throw std::runtime_error("Conditional::negLogConstant is not implemented");
 }
 
 /* ************************************************************************* */
 template <class FACTOR, class DERIVEDCONDITIONAL>
 double Conditional<FACTOR, DERIVEDCONDITIONAL>::normalizationConstant() const {
-  return std::exp(logNormalizationConstant());
+  return std::exp(-negLogConstant());
 }
 
 /* ************************************************************************* */
@@ -90,8 +81,8 @@ bool Conditional<FACTOR, DERIVEDCONDITIONAL>::CheckInvariants(
   const double logProb = conditional.logProbability(values);
   if (std::abs(prob_or_density - std::exp(logProb)) > 1e-9)
     return false;  // logProb is not consistent with prob_or_density
-  if (std::abs(conditional.logNormalizationConstant() -
-               std::log(conditional.normalizationConstant())) > 1e-9)
+  if (std::abs(conditional.negLogConstant() -
+               (-std::log(conditional.normalizationConstant()))) > 1e-9)
     return false;  // log normalization constant is not consistent with
                    // normalization constant
   const double error = conditional.error(values);

gtsam/inference/Conditional.h

@@ -39,7 +39,8 @@ namespace gtsam {
    * logProbability(x) = -(K + error(x))
    * i.e., K = -log(k). The normalization constant k is assumed to *not* depend
    * on any argument, only (possibly) on the conditional parameters.
-   * This class provides a default logNormalizationConstant() == 0.0.
+   * This class provides a default negative log normalization constant
+   * negLogConstant() == 0.0.
    * 
    * There are four broad classes of conditionals that derive from Conditional:
    *
@@ -165,19 +166,13 @@ namespace gtsam {
 
     /**
      * @brief All conditional types need to implement this as the negative log
-     * of the normalization constant.
+     * of the normalization constant to make it such that error>=0.
      *
      * @return double
      */
     virtual double negLogConstant() const;
 
-    /**
-     * All conditional types need to implement a log normalization constant to
-     * make it such that error>=0.
-     */
-    virtual double logNormalizationConstant() const;
-
-    /** Non-virtual, exponentiate logNormalizationConstant. */
+    /** Non-virtual, negate and exponentiate negLogConstant. */
     double normalizationConstant() const;
 
     /// @}
@@ -217,9 +212,9 @@ namespace gtsam {
      *  - evaluate >= 0.0
      *  - evaluate(x) == conditional(x)
      *  - exp(logProbability(x)) == evaluate(x)
-     *  - logNormalizationConstant() = log(normalizationConstant())
+     *  - negLogConstant() = -log(normalizationConstant())
      *  - error >= 0.0
-     *  - logProbability(x) == logNormalizationConstant() - error(x)
+     *  - logProbability(x) == -(negLogConstant() + error(x))
      *
      * @param conditional The conditional to test, as a reference to the derived type.
      * @tparam VALUES HybridValues, or a more narrow type like DiscreteValues.

gtsam/linear/GaussianBayesNet.cpp

@@ -243,25 +243,24 @@ namespace gtsam {
   }
 
   /* ************************************************************************* */
-  double GaussianBayesNet::logNormalizationConstant() const {
+  double GaussianBayesNet::negLogConstant() const {
     /*
     normalization constant = 1.0 / sqrt((2*pi)^n*det(Sigma))
-    logConstant = -log(normalizationConstant)
-      = -0.5 * n*log(2*pi) - 0.5 * log(det(Sigma))
+    negLogConstant = -log(normalizationConstant)
+      = 0.5 * n*log(2*pi) + 0.5 * log(det(Sigma))
 
     log(det(Sigma)) = -2.0 * logDeterminant()
-    thus, logConstant = -0.5*n*log(2*pi) + logDeterminant()
+    thus, negLogConstant = 0.5*n*log(2*pi) - logDeterminant()
 
-    BayesNet logConstant = sum(-0.5*n_i*log(2*pi) + logDeterminant_i())
-    = sum(-0.5*n_i*log(2*pi)) + sum(logDeterminant_i())
-    = sum(-0.5*n_i*log(2*pi)) + bn->logDeterminant()
-    = sum(logNormalizationConstant_i)
+    BayesNet negLogConstant = sum(0.5*n_i*log(2*pi) - logDeterminant_i())
+    = sum(0.5*n_i*log(2*pi)) + sum(logDeterminant_i())
+    = sum(0.5*n_i*log(2*pi)) + bn->logDeterminant()
     */
-    double logNormConst = 0.0;
+    double negLogNormConst = 0.0;
     for (const sharedConditional& cg : *this) {
-      logNormConst += cg->logNormalizationConstant();
+      negLogNormConst += cg->negLogConstant();
     }
-    return logNormConst;
+    return negLogNormConst;
   }
 
   /* ************************************************************************* */

gtsam/linear/GaussianBayesNet.h

@@ -235,12 +235,12 @@ namespace gtsam {
     double logDeterminant() const;
 
     /**
-     * @brief Get the log of the normalization constant corresponding to the
-     * joint Gaussian density represented by this Bayes net.
+     * @brief Get the negative log of the normalization constant corresponding
+     * to the joint Gaussian density represented by this Bayes net.
      *
      * @return double
      */
-    double logNormalizationConstant() const;
+    double negLogConstant() const;
 
     /**
      * Backsubstitute with a different RHS vector than the one stored in this BayesNet.

gtsam/linear/GaussianConditional.cpp

@@ -121,7 +121,7 @@ namespace gtsam {
       const auto mean = solve({});  // solve for mean.
       mean.print("  mean", formatter);
     }
-    cout << "  logNormalizationConstant: " << logNormalizationConstant() << endl;
+    cout << "  logNormalizationConstant: " << -negLogConstant() << endl;
     if (model_)
       model_->print("  Noise model: ");
     else
@@ -198,7 +198,7 @@ namespace gtsam {
   //  density = k exp(-error(x))
   //  log = log(k) - error(x)
   double GaussianConditional::logProbability(const VectorValues& x) const {
-    return logNormalizationConstant() - error(x);
+    return -(negLogConstant() + error(x));
   }
 
   double GaussianConditional::logProbability(const HybridValues& x) const {

gtsam/linear/NoiseModel.cpp

@@ -266,11 +266,6 @@ double Gaussian::negLogConstant() const {
   return 0.5 * n * log2pi - logDetR();
 }
 
-/* *******************************************************************************/
-double Gaussian::logNormalizationConstant() const {
-  return -negLogConstant();
-}
-
 /* ************************************************************************* */
 // Diagonal
 /* ************************************************************************* */

gtsam/linear/NoiseModel.h

@@ -273,20 +273,12 @@ namespace gtsam {
 
       /**
        * @brief Compute the negative log of the normalization constant
-       * for a Gaussian noise model k = \sqrt(1/|2πΣ|).
+       * for a Gaussian noise model k = 1/\sqrt(|2πΣ|).
        * 
        * @return double 
        */
       double negLogConstant() const;
 
-      /**
-       * @brief Method to compute the normalization constant
-       * for a Gaussian noise model k = \sqrt(1/|2πΣ|).
-       *
-       * @return double
-       */
-      double logNormalizationConstant() const;
-
      private:
 #ifdef GTSAM_ENABLE_BOOST_SERIALIZATION
       /** Serialization function */

gtsam/linear/linear.i

@@ -549,7 +549,6 @@ virtual class GaussianConditional : gtsam::JacobianFactor {
   
   // Standard Interface
   double negLogConstant() const;
-  double logNormalizationConstant() const;
   double logProbability(const gtsam::VectorValues& x) const;
   double evaluate(const gtsam::VectorValues& x) const;
   double error(const gtsam::VectorValues& x) const;

gtsam/linear/tests/testGaussianBayesNet.cpp

@@ -76,12 +76,11 @@ TEST(GaussianBayesNet, Evaluate1) {
   // the normalization constant 1.0/sqrt((2*pi*Sigma).det()).
   // The covariance matrix inv(Sigma) = R'*R, so the determinant is
   const double constant = sqrt((invSigma / (2 * M_PI)).determinant());
-  EXPECT_DOUBLES_EQUAL(log(constant),
-                       smallBayesNet.at(0)->logNormalizationConstant() +
-                           smallBayesNet.at(1)->logNormalizationConstant(),
-                       1e-9);
-  EXPECT_DOUBLES_EQUAL(log(constant), smallBayesNet.logNormalizationConstant(),
+  EXPECT_DOUBLES_EQUAL(-log(constant),
+                       smallBayesNet.at(0)->negLogConstant() +
+                           smallBayesNet.at(1)->negLogConstant(),
                        1e-9);
+  EXPECT_DOUBLES_EQUAL(-log(constant), smallBayesNet.negLogConstant(), 1e-9);
   const double actual = smallBayesNet.evaluate(mean);
   EXPECT_DOUBLES_EQUAL(constant, actual, 1e-9);
 }

gtsam/linear/tests/testGaussianConditional.cpp

@@ -486,17 +486,17 @@ TEST(GaussianConditional, Error) {
 
 /* ************************************************************************* */
 // Similar test for multivariate gaussian but with sigma 2.0
-TEST(GaussianConditional, LogNormalizationConstant) {
+TEST(GaussianConditional, NegLogConstant) {
   double sigma = 2.0;
   auto conditional = GaussianConditional::FromMeanAndStddev(X(0), Vector3::Zero(), sigma);
   VectorValues x;
   x.insert(X(0), Vector3::Zero());
   Matrix3 Sigma = I_3x3 * sigma * sigma;
-  double expectedLogNormalizationConstant =
-      log(1 / sqrt((2 * M_PI * Sigma).determinant()));
+  double expectedNegLogConstant =
+      -log(1 / sqrt((2 * M_PI * Sigma).determinant()));
 
-  EXPECT_DOUBLES_EQUAL(expectedLogNormalizationConstant,
-                       conditional.logNormalizationConstant(), 1e-9);
+  EXPECT_DOUBLES_EQUAL(expectedNegLogConstant, conditional.negLogConstant(),
+                       1e-9);
 }
 
 /* ************************************************************************* */

gtsam/linear/tests/testNoiseModel.cpp

@@ -807,50 +807,50 @@ TEST(NoiseModel, NonDiagonalGaussian)
   }
 }
 
-TEST(NoiseModel, LogNormalizationConstant1D) {
+TEST(NoiseModel, NegLogNormalizationConstant1D) {
   // Very simple 1D noise model, which we can compute by hand.
   double sigma = 0.1;
-  // For expected values, we compute log(1/sqrt(|2πΣ|)) by hand.
-  // = -0.5*(log(2π) + log(Σ)) (since it is 1D)
-  double expected_value = -0.5 * log(2 * M_PI * sigma * sigma);
+  // For expected values, we compute -log(1/sqrt(|2πΣ|)) by hand.
+  // = 0.5*(log(2π) - log(Σ)) (since it is 1D)
+  double expected_value = 0.5 * log(2 * M_PI * sigma * sigma);
 
   // Gaussian
   {
     Matrix11 R;
     R << 1 / sigma;
     auto noise_model = Gaussian::SqrtInformation(R);
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
   // Diagonal
   {
     auto noise_model = Diagonal::Sigmas(Vector1(sigma));
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
   // Isotropic
   {
     auto noise_model = Isotropic::Sigma(1, sigma);
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
   // Unit
   {
     auto noise_model = Unit::Create(1);
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     double sigma = 1.0;
-    expected_value = -0.5 * log(2 * M_PI * sigma * sigma);
+    expected_value = 0.5 * log(2 * M_PI * sigma * sigma);
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
 }
 
-TEST(NoiseModel, LogNormalizationConstant3D) {
+TEST(NoiseModel, NegLogNormalizationConstant3D) {
   // Simple 3D noise model, which we can compute by hand.
   double sigma = 0.1;
   size_t n = 3;
-  // We compute the expected values just like in the LogNormalizationConstant1D
+  // We compute the expected values just like in the NegLogNormalizationConstant1D
   // test, but we multiply by 3 due to the determinant.
-  double expected_value = -0.5 * n * log(2 * M_PI * sigma * sigma);
+  double expected_value = 0.5 * n * log(2 * M_PI * sigma * sigma);
 
   // Gaussian
   {
@@ -859,27 +859,27 @@ TEST(NoiseModel, LogNormalizationConstant3D) {
         0, 1 / sigma, 4,   //
         0, 0, 1 / sigma;
     auto noise_model = Gaussian::SqrtInformation(R);
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
   // Diagonal
   {
     auto noise_model = Diagonal::Sigmas(Vector3(sigma, sigma, sigma));
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
   // Isotropic
   {
     auto noise_model = Isotropic::Sigma(n, sigma);
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
   // Unit
   {
     auto noise_model = Unit::Create(3);
-    double actual_value = noise_model->logNormalizationConstant();
+    double actual_value = noise_model->negLogConstant();
     double sigma = 1.0;
-    expected_value = -0.5 * n * log(2 * M_PI * sigma * sigma);
+    expected_value = 0.5 * n * log(2 * M_PI * sigma * sigma);
     EXPECT_DOUBLES_EQUAL(expected_value, actual_value, 1e-9);
   }
 }