rodent (the Rapid ODE iNTegrator) is a C++ library for integrating ordinary differential equations (ODEs). The function to be integrated is passed as a template parameter, rather than a function pointer, to allow the compiler to aggressively inline.
rodent was written and is maintained by Jean-Luc Thiffeault.
The header files in the rodent folder are standalone with no associated .cpp files, so no special linking is required. Examples of usage are in the testsuite folder. When compiling, the root folder of the rodent project must be in the include path. For example, you can compile the program simpharmonic.cpp in the testsuite folder with
g++ -O -I.. -o simpharmonic simpharmonic.cpp
To compile all the examples, run make from the testsuite folder.
To see if inlining is working properly, type make inline_test from the testsuite folder:
> make inline_test
Compile without inlining:
g++ -Wall -c -I.. -I../extern/jlt inline_test.cpp
Disassembly shows the right-hand side function is called:
objdump -Cd inline_test.o \
| grep --color SimpleHarmonic\<double\>::operator\(\)
0000000000000000 <SimpleHarmonic<double>::operator()(double, std::vector<double, std::allocator<double> > const&, std::vector<double, std::allocator<double> >&)>:
26: e8 00 00 00 00 callq 2b <SimpleHarmonic<double>::operator()(double, std::vector<double, std::allocator<double> > const&, std::vector<double, std::allocator<double> >&)+0x2b>
3a: e8 00 00 00 00 callq 3f <SimpleHarmonic<double>::operator()(double, std::vector<double, std::allocator<double> > const&, std::vector<double, std::allocator<double> >&)+0x3f>
51: e8 00 00 00 00 callq 56 <SimpleHarmonic<double>::operator()(double, std::vector<double, std::allocator<double> > const&, std::vector<double, std::allocator<double> >&)+0x56>
62: f2 0f 10 05 00 00 00 movsd 0x0(%rip),%xmm0 # 6a <SimpleHarmonic<double>::operator()(double, std::vector<double, std::allocator<double> > const&, std::vector<double, std::allocator<double> >&)+0x6a>
7f: e8 00 00 00 00 callq 84 <SimpleHarmonic<double>::operator()(double, std::vector<double, std::allocator<double> > const&, std::vector<double, std::allocator<double> >&)+0x84>
Compile with inlining (-O):
g++ -Wall -c -O -I.. -I../extern/jlt inline_test.cpp
Function not found in objdump (good)!
The right-hand side function does not appear in the disassembly.The first compilation, without inlining, shows that the function call to the right-hand side function SimpleHarmonic<double>::operator() does indeed show up in the object dump. In the second, with inlining turned on, the grep command finds no call to the function. This is possible because the right-hand side function is passed to the integrator as a template argument rather than a function pointer, so is available at compile time. This also means that a new integrator is created for each function to be integrated.
rodent is released under the MIT License.