[OMPI users] speed up this problem by MPI

[Tim]

Hi,

(1). I am wondering how I can speed up the time-consuming computation in the 
loop of my code below using MPI?

     int main(int argc, char ** argv)   
     {   
     // some operations           
     f(size);           
     // some operations         
     return 0;   
     }   

     void f(int size)   
     {   
     // some operations          
     int i;           
     double * array =  new double [size];           
     for (i = 0; i < size; i++) // how can I use MPI to speed up this loop to 
compute all elements in the array?   
     {   
     array[i] = complicated_computation(); // time comsuming computation   
     }           
     // some operations using all elements in array           
     delete [] array;  
     }

As shown in the code, I want to do some operations before and after the part to 
be paralleled with MPI, but I don't know how to specify where the parallel part 
begins and ends.

(2) My current code is using OpenMP to speed up the comutation. 

     void f(int size)   
     {   
     // some operations           
     int i;           
     double * array =  new double [size];   
     omp_set_num_threads(_nb_threads);  
     #pragma omp parallel shared(array) private(i)  
     {
     #pragma omp for schedule(dynamic) nowait          
     for (i = 0; i < size; i++) // how can I use MPI to speed up this loop to 
compute all elements in the array?   
     {   
     array[i] = complicated_computation(); // time comsuming computation   
     }          
     } 
     // some operations using all elements in array           
     }

I wonder if I change to use MPI, is it possible to have the code written both 
for OpenMP and MPI? If it is possible, how to write the code and how to compile 
and run the code?

Thanks and regards!