ceres-solver/internal/ceres/expression_graph_test.cc

// Ceres Solver - A fast non-linear least squares minimizer
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// http://code.google.com/p/ceres-solver/
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// Author: darius.rueckert@fau.de (Darius Rueckert)
//
// Test expression creation and logic.

#include "ceres/internal/expression_graph.h"
#include "ceres/internal/expression_ref.h"

#include "gtest/gtest.h"

namespace ceres {
namespace internal {

TEST(ExpressionGraph, Creation) {
  using T = ExpressionRef;
  ExpressionGraph graph;

  StartRecordingExpressions();
  graph = StopRecordingExpressions();
  EXPECT_EQ(graph.Size(), 0);

  StartRecordingExpressions();
  T a(1);
  T b(2);
  T c = a + b;
  graph = StopRecordingExpressions();
  EXPECT_EQ(graph.Size(), 3);
}

TEST(ExpressionGraph, Dependencies) {
  using T = ExpressionRef;

  StartRecordingExpressions();

  T unused(6);
  T a(2), b(3);
  T c = a + b;
  T d = c + a;

  auto tree = StopRecordingExpressions();

  // Recursive dependency check
  ASSERT_TRUE(tree.DependsOn(d.id, c.id));
  ASSERT_TRUE(tree.DependsOn(d.id, a.id));
  ASSERT_TRUE(tree.DependsOn(d.id, b.id));
  ASSERT_FALSE(tree.DependsOn(d.id, unused.id));
}

}  // namespace internal
}  // namespace ceres