/********************************************************************
                   C-DAC Tech Workshop : hyPACK-2013 
                         October 15-18, 2013 

 Example 1.10          : omp-workshare-section.c

 Objective             : Write an OpenMP Program to illustrate Work-Sharing section.
		  	  In this , the OpenMP SECTION directive is used to assign
   		 	  different  operations to each thread that executes a SECTION.

 Input                 : a) Number of threads

                  	 b) Size of matrices (numofrows and noofcols )

 Output                : Time taken by the parallel and serial computation                                            

 Created               : August-2013

 E-mail                : hpcfte@cdac.in     

************************************************************************/

#include <stdio.h>
#include <sys/time.h>
#include <omp.h>
#include <math.h>
#include <stdlib.h>

/* Main Program */
main(int argc,char **argv)
{

	int            NoofCols,NoofRows,index,VectorSize,icol,vec_col,irow,MatrixFileStatus=1,VectorFileStatus=1;
	int             matrowsize,matcolsize,vectorsize;
	float         **Matrix, **Matrix_one,*Vector, *Result_Vector;
        FILE           *fp1; 
 	struct 		timeval  TimeValue_Start, TimeValue1_Start;
        struct 		timezone TimeZone_Start, TimeZone1_Start;


        struct 		timeval  TimeValue_Final, TimeValue1_Final;
        struct 		timezone TimeZone_Final, TimeZone1_Final;
        long            time_start, time_end;
        double          time_overhead1,time_overhead2;

	int icol1 ,irow1;


	printf("\n\t\t---------------------------------------------------------------------------");
        printf("\n\t\t Centre for Development of Advanced Computing (C-DAC)");
        printf("\n\t\t Email : hpcfte@cdac.in");
        printf("\n\t\t---------------------------------------------------------------------------");
        printf("\n\t\t Objective : OpenMP Work-Sharing Construct .");
        printf("\n\t\t The OpenMP SECTION directive is used to assign different  operations to each ");
        printf("\n\t\t thread that executes a SECTION."); 
        printf("\n\t\t OpenMP Work-Shareing Construct : SECTION Directive . ");
        printf("\n\t\t..........................................................................\n");

       if(argc != 4){

	 	printf("\t\t Very Few Arguments\n ");
           	printf("\t\t Syntax : exec <NoOfRows> <NoOfColums> <Vector-size>  \n");
           	exit(-1);

       }


       /* printf("\n\t\t Enter the No. of Rows and Columns of Matrix and Vector Size \n");

        scanf("%d%d%d",&matrowsize,&matcolsize,&vectorsize); */

         matrowsize = atoi(argv[1]);
         matcolsize = atoi(argv[2]);
         vectorsize = atoi(argv[3]);

          if( matcolsize != vectorsize) {

                printf("\n\n\t\t Matrix into vertor multiplication not possible ");
                printf("\n\t\t Vector Size != Matrix Col size \n");
                exit(-1);
          }  

       /* .......................................................................................

          The OpenMP SECTION directive is used to assign different  operations to each 
          thread that executes a SECTION. 

		- One thread will do the file operation
                - Second thread will do the matrix vector computation 

         ........................................................................................*/

  	gettimeofday(&TimeValue_Start, &TimeZone_Start);
	omp_set_num_threads(2);
      	#pragma omp parallel  
     	{
           #pragma omp sections 
           {
             #pragma omp section 
             {
                	printf("\n\n\t\t %d - Thread is doing section 1 ", omp_get_thread_num());  
  			if ((fp1 = fopen ("./data/mdata.inp", "r")) == NULL){
				printf("\n\t\t Failed to open the file\n "); 
       				MatrixFileStatus = 0;
  			}

				if(MatrixFileStatus != 0) 
				{
						/*
						fscanf(fp1,"%d%d\n",&NoofRows,&NoofCols);
	
						Matrix = (float **)malloc(NoofRows*sizeof(float *));
						
						for(irow=0 ;irow<NoofRows; irow++)
						{
							Matrix[irow] = (float *)malloc(NoofCols*sizeof(float));
							for(icol=0; icol<NoofCols; icol++) 
										fscanf(fp1,"%f",&Matrix[irow][icol]);
						}
	
						;
						free(Matrix);
						 */
						 
						fclose(fp1);
				}
          	}
			
               #pragma omp section 
               {  	
	
       	       		printf("\n\n\t\t %d - Thread is doing section 2 ", omp_get_thread_num());  
    		 	Matrix_one = (float **)malloc( matrowsize *sizeof(float *));
    		 	Vector = (float *)malloc( vectorsize *sizeof(float));
    		 	Result_Vector = (float *)malloc(matrowsize  *sizeof(float));
			
		 	for(irow1=0 ; irow1<matrowsize ; irow1++)
                 	{

 	 			Matrix_one[irow1] = (float *)malloc(matcolsize * sizeof(float));
 	 			for(icol1=0; icol1<matcolsize; icol1++) {
    	    				Matrix_one[irow1][icol1] = (irow1*1.0) ;
                        		Vector[irow1] = (icol1*1.0) ;
                        		Result_Vector[irow1] = 0.0;

       	 			}

                	}
			
               		for(icol1 = 0; icol1 < matrowsize ; icol1++)
                    		for(irow1 = 0 ; irow1 < matcolsize; irow1++)
                       		{
                      			Result_Vector[icol1] = Result_Vector[icol1] + Vector[irow1] * Matrix_one[irow1][icol1]; 
                       		} 
		
			free(Matrix_one);
              		free(Vector);
              		free(Result_Vector); 
			
             	}

        }  /* End of sections */

   } /* End of parallel section */

	gettimeofday(&TimeValue_Final, &TimeZone_Final);


        time_start = TimeValue_Start.tv_sec * 1000000 + TimeValue_Start.tv_usec;
        time_end = TimeValue_Final.tv_sec * 1000000 + TimeValue_Final.tv_usec;
        time_overhead1 = (time_end - time_start)/1000000.0;

	/*.................................................................................

          	This section implement the above section in serial way
           ...............................................................................*/

      	/* Serial computation */

  	gettimeofday(&TimeValue1_Start, &TimeZone1_Start);

	 /* .......Read the Input file ......*/

         if ((fp1 = fopen ("./data/mdata.inp", "r")) == NULL){
         	printf("\n\t\t Failed to open the file\n ");
                MatrixFileStatus = 0;
         }


         if(MatrixFileStatus != 0) {
                 fscanf(fp1,"%d%d\n",&NoofRows,&NoofCols);

                /* ...Allocate memory and read Matrix from file .......*/

                 Matrix = (float **)malloc(NoofRows*sizeof(float *));

                for(irow=0 ;irow<NoofRows; irow++){
                        Matrix[irow] = (float *)malloc(NoofCols*sizeof(float));
                                for(icol=0; icol<NoofCols; icol++) {
                                        fscanf(fp1,"%f",&Matrix[irow][icol]);

                                }

                }

                fclose(fp1);
                free(Matrix);
          }

			Matrix_one = (float **)malloc( matrowsize *sizeof(float *));
                        Vector = (float *)malloc( vectorsize *sizeof(float));
                        Result_Vector = (float *)malloc(matrowsize  *sizeof(float));

                        for(irow=0 ; irow<matrowsize ; irow++)
                        {
                                Matrix_one[irow] = (float *)malloc(matcolsize * sizeof(float));
                                for(icol=0; icol<matcolsize; icol++) {
                                        Matrix_one[irow][icol] = cos(irow*1.0) ;
                                        Vector[irow] = cos(icol*1.0) ;
                                        Result_Vector[irow] = 0.0;
                                }

                        }
                        for(icol = 0; icol < matrowsize ; icol++)
                                for(irow = 0 ; irow < matcolsize; irow++)
                                {
                                        Result_Vector[icol] = Result_Vector[icol] + Vector[irow] * Matrix_one[irow][icol];
                                }
                        free(Matrix_one);
                        free(Vector);
                        free(Result_Vector);

	gettimeofday(&TimeValue1_Final, &TimeZone1_Final);

        time_start = 0;
        time_end = 0;

        time_start = TimeValue1_Start.tv_sec * 1000000 + TimeValue1_Start.tv_usec;
        time_end = TimeValue1_Final.tv_sec * 1000000 + TimeValue1_Final.tv_usec;
        time_overhead2 = (time_end - time_start)/1000000.0;

	printf("\n\n\t\t Time Taken (By Parallel Computation )    :%lf  ", time_overhead1);
	printf("\n\t\t Time Taken (By Serial Computation )      :%lf \n ", time_overhead2);
        printf("\n\t\t..........................................................................\n");


}