Merge pull request #572 from borglab/feature/symbol-alternative-names

Add alternativeName() for symbols

gtsam/inference/Symbol.h

@@ -164,8 +164,16 @@ inline Key Y(std::uint64_t j) { return Symbol('y', j); }
 inline Key Z(std::uint64_t j) { return Symbol('z', j); }
 }
 
+/** Generates symbol shorthands with alternative names different than the
+ * one-letter predefined ones. */
+class SymbolGenerator {
+  const char c_;
+public:
+  SymbolGenerator(const char c) : c_(c) {}
+  Symbol operator()(const std::uint64_t j) const { return Symbol(c_, j); }
+};
+
 /// traits
 template<> struct traits<Symbol> : public Testable<Symbol> {};
 
 } // \ namespace gtsam
-

gtsam/inference/tests/testKey.cpp

@@ -40,6 +40,25 @@ TEST(Key, KeySymbolConversion) {
   EXPECT(assert_equal(original, actual))
 }
 
+/* ************************************************************************* */
+TEST(Key, SymbolGenerator) {
+  const auto x1 = gtsam::symbol_shorthand::X(1);
+  const auto v1 = gtsam::symbol_shorthand::V(1);
+  const auto a1 = gtsam::symbol_shorthand::A(1);
+
+  const auto Z = gtsam::SymbolGenerator('x');
+  const auto DZ = gtsam::SymbolGenerator('v');
+  const auto DDZ = gtsam::SymbolGenerator('a');
+
+  const auto z1 = Z(1);
+  const auto dz1 = DZ(1);
+  const auto ddz1 = DDZ(1);
+
+  EXPECT(assert_equal(x1, z1));
+  EXPECT(assert_equal(v1, dz1));
+  EXPECT(assert_equal(a1, ddz1));
+}
+
 /* ************************************************************************* */
 template<int KeySize>
 Key KeyTestValue();
@@ -106,4 +125,3 @@ int main() {
   return TestRegistry::runAllTests(tr);
 }
 /* ************************************************************************* */
-