passed parameters to boost odeint in C++ - c++

Question

This answer is helpful, but I would like to know how to pass multiple parameters of different types to the ODE model, perhaps in a struct. For my immediate use case, I need to be able to pass one std::array<double, 6>, two std::vector<std::vector<double>> and two two double scalars for a total of four parameters to be passed. In the linked example, as well as in harmonic_oscillator.cpp, there is only a single double passed parameter. Thanks.
Here's an example of the struct I would need passed to the ODE force model and used within the rate equations.
struct T
{
std::array<double, 6> IC;
double S;
double M;
std::vector<std::vector<double>> C;
std::vector<std::vector<double>> WT;
};

Answer 1

I believe I've come up with a struct solution that works, but am not sure if it has any variable/memory scope no-no's. Here's an example:
#include <vector>
#include <boost/numeric/odeint.hpp>
// define structure
struct T
{
std::array<double, 6> IC;
double S;
};
// force model
class harm_osc
{
struct T T1;
public:
harm_osc(struct T G) : T1(G) {}
void operator() ( const std::vector< double > &x , std::vector< double > &dxdt , const double /* t */ )
{
dxdt[0] = x[1];
dxdt[1] = -x[0] - T1.IC[0]*x[1] + T1.S;
}
};
// print integrated state solution
void write_solution( const std::vector< double > &x , const double t )
{
printf("%-6.2f %-6.2f %-6.2f\n", t, x[0], x[1]);
}
// problem setup
int main()
{
std::vector< double > x(2);
x[0] = 1.0;
x[1] = 0.0;
struct T T2;
T2.IC = {0.15, 0.15, 0.15, 0.15, 0.15, 0.15};
T2.S = 0.0;
harm_osc ho(T2);
boost::numeric::odeint::integrate(ho, x, 0.0, 10.0, 0.1, write_solution);
}