Vector Usage in MPI(C++)

Question

I am new to MPI programming,stiil learning , i was successful till creating the Derived data-types by defining the structures . Now i want to include Vector in my structure and want to send the data across the Process. for ex:

struct Structure{

//Constructor 
Structure(): X(nodes),mass(nodes),ac(nodes) {

//code to calculate the mass and accelerations
}
//Destructor
Structure() {}

//Variables
double radius;
double volume;
vector<double> mass;
vector<double> area;

//and some other variables

//Methods to calculate some physical properties

Now using MPI i want to sent the data in the structure across the processes. Is it possible for me to create the MPI_type_struct vectors included and send the data?

I tried reading through forums, but i am not able to get the clear picture from the responses given there. Hope i would be able to get a clear idea or approach to send the data

PS: i can send the data individually , but its an overhead of sending the data using may MPI_Send/Recieve if we consider the domain very large(say 10000*10000)

Answer 1

Defining structures in MPI is a pain. I think an easier approach would be to use the fact that STL vectors are guaranteed to have contiguously allocated memory. That is, you can treat them like C arrays by getting a pointer to the first element.

std::vector<float> data;
// ... add elements to your vector ...
MPI_Send(&data.front(), data.size(), MPI_FLOAT, 0, 1, MPI_COMM_WORLD);