Parallelize for-loop by MPI?

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

Code:

     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. Elements are computed independently of each other.  
     }           
     // 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.

I am not sure, but you can look for OpenMP

OpenMP is for multi-processor systems support.