Threads\Process

This is a discussion on Threads\Process within the C Programming forums, part of the General Programming Boards category; Can somebody help me out? -------------------------------------- Input: Square matrix A of nxn integers, where n is even. Rotate the elements ...

  1. #1
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    Threads\Process

    Can somebody help me out?
    --------------------------------------
    Input: Square matrix A of nxn integers, where n is even.

    Rotate the elements of both diagonals in the clock direction.

    Input matrix 4x4

    1 2 3 4
    5 6 7 8
    9 10 11 12
    13 14 15 16

    Matrix 4x4 after rotation:

    13 2 3 1
    5 10 6 8
    9 11 7 12
    16 14 15 4

    Rotation is executed by 2n threads/processes.
    One quarter n/2 of threads/processes can
    read data from the upper half of the
    main diagonal (e.g. 4,7) and write them
    to the lower half of the secondary diagonal (e.g. 11,16).
    The second quarter of threads/processes can read data from
    the lower half of the secondary diagonal (e.g. 11,16) and
    write them to the lower half of the main diagonal (e.g. 10,13).
    The third quarter of threads/processes can read data from the
    lower half of the main diagonal (e.g. 10,13) and write them to
    the upper half of the secondary diagonal (e.g. 1,6). The last
    quarter of threads/processes can read data from the upper half of
    the secondary diagonal (e.g. 1,6) and write them to the upper
    half of the main diagonal (e.g. 4,7).

    Output: Input and output matrix.

    -------------------------------
    I've tried to begin the code so just pick out some mistakes and correct so that it can work..Thanks
    ----------------------------------
    Code:
    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <errno.h>
    #include <unistd.h>
    #include <pthread.h>
    #include <math.h>
    #define MAX_THREADS  100
    
    int Elmnt[10000];
    int **tmp;
    int m, n, Elmntsize, t, k, kAbs;
    pthread_mutex_t mutex;
    pthread_cond_t cond[MAX_THREADS];
    
    /////////////////////////////////////
    void Print () {
      int i;
      for(i=0; i<Elmntsize; i++){
        if((i+1)%n == 0 && i != 0) {
           printf("%d\n",Elmnt[i]); 
        }
        else
         printf("%d ",Elmnt[i]);  
      }
      printf("\n");  
    }
    
    
     ////////////////////////////////
    //       read file     //
    int  Readfile(char *fname){
      FILE *f;
      int i;
      f = fopen(fname, "r");
      if (f == NULL) {
        fprintf(stderr, "file \"%s\" cannot open.\n", fname);
        return -1;
      }
      fscanf(f,"%d %d",&m, &n);
      Elmntsize = m*n;
      for (i=0; i < Elmntsize; i++){
        fscanf(f,"%d",&Elmnt[i]);
      }   
      fclose(f);
      return 0;  
    }
    
    
     ////////////////////////////////////////////////////////
    //       Find the average number of threads  //
    int avgCntRwTh(){
      if(m == t) return 1;
      if(t == 1) return m;
      return floor((float)m/t+0.5);
    }
    
    
     /////////////////////////////////////////////////////////////////////////
    //   SHift of auxiliary tmp to new position(for right rotation)      //
    void tmpShiftRR(int id, int iL){
      int i, preID;  
      if(id == 0) preID = t-1;
        else preID = id-1;
      for (i=0; i<kAbs; i++){
        Elmnt[iL+i]= tmp[preID][kAbs-1-i];
      } 
    }
     ----------------------------------------
    //       right rotation function      //
    ----------------------------------------
    void RotationR(int id, int iL, int iR){
      int i;  
      for (i=0; i<kAbs; i++){
        tmp[id][i] = Elmnt[iR-i];
      }  
      for (i=iR-kAbs; i>=iL; i--){
    Elmnt[i+kAbs] = Elmnt[i];
      }  
      if(id == t-1) {
        tmpShift(id, iL);
        pthread_cond_signal(&cond[0]);    
      } 
      else { 
        pthread_cond_wait(&cond[id], &mutex); 
        tmpShiftRR(id, iL);
        pthread_cond_signal(&cond[id+1]);
      }  
    }
    ---------------------------------------
    //       Left rotation function      //
    ---------------------------------------
    void RotationL(int id, int iL, int iR){
      int i;  
      for (i=0; i<kAbs; i++){ tmp[id][i] = Elmnt[iL+i]; }  
      for (i=iL; i<=iR; i++){ Elmnt[i] = Elmnt[i+kAbs];  }  
      if(id == t-1) {
        tmpShiftRL(id, iR);  
      } 
      else { 
        pthread_cond_wait(&cond[id], &mutex); 
        tmpShiftRL(id, iR);
      }  
      if(id != 0) pthread_cond_signal(&cond[id-1]);
    }
    
    
     --------------------
    //  rotate      //  
    --------------------
    void *rotate(void *threadid){
      int id, cntR, pocR, konR, iL, iR;
      id = (int)threadid;
      printf("The working Thread is number: %d\n", id+1);
      cntR = avgCntRwTh();                         // To find out how many rows to be worked on average amount
      pocR = (id)*cntR+1;                          // To provide rows where to begin rotation
      if(id == t-1) {
        cntR = m - (t-1)*cntR;
        sleep(1);
      }     // For the Last thread of the remaining rows.
      konR = pocR+cntR -1;
      printf("     - This Threa is working with rows: %d-%d\n", pocR, konR);
      //
      iL = (pocR-1)*n;           //First element of respective Thread
      iR = konR*n -1;            // Last element 
      //
      pthread_mutex_lock(&mutex);  
      //
      if(k < 0) rotationL(id, iL, iR);              // left
        else    rotationR(id, iL, iR);              // right
      // 
      pthread_mutex_unlock(&mutex); 
      //
      pthread_exit(NULL);  
      return NULL;  
    }  
    
    
    
        
    ----------------------------------
    //             main            //
    -----------------------------------
    int main(int argc, char *argv[])
    {
      char File;
      int i, j, kN;
      pthread_t ths[MAX_THREADS];
     
      do {     
           // The reading of data from the file
        do {
          printf("\nType the name of the file (pro ukonceni programu: -1): ");
          scanf("%s", &File);
          if(atoi(&File) == -1) exit(0);
        } 
        while(ReadFile(&File) != 0 );
        printf("\nThe file was read:\n");
        Print();
            // The given number of Thread  
        do {
          printf("Type total number of Threads(1-%d): ", m);
          scanf("%d", &t);
          if(t == -1) exit(0);
        } 
        while(t < 1 || t > m); 
        if(t>MAX_THREADS) t = MAX_THREADS;
       
           // The number of positions to be rotated  
        printf("Enter number of positions to be rotated: ");
        scanf("%d", &k);
        kAbs = abs(k);
        if(kAbs > ElmntSize-1 && k >= 0) kAbs = kAbs %ElmntSize;      // oriznuti kroku na velikost pole
        if(kAbs > ElmntSize && k < 0) kAbs = kAbs %ElmntSize;   
        kN = kAbs /n;                                                 // pocet presahu na dalsi radek
        kAbs = kAbs %n;                                               // total number of positions during the first pass                                          
          // alokovani pomocneho 2d pole pro pomocne presuny   
        tmp = (int **)malloc(t*sizeof(int*));  
        for(i=0; i<t; i++)               
          tmp[i]=(int *)malloc(n*sizeof(int));
    
          //  Created Thread
        pthread_mutex_init(&mutex, NULL);
        for (j=0; j<=kN; j++){
          if (kAbs == 0) { kAbs = n; continue; }
          for(i=0; i<t; i++) {
            if(pthread_cond_init (&cond[i], NULL)) {
              printf("ERROR:During pthread_cond_init() - number %d\n)", i); exit(-1); 
            }
            if(pthread_create(&ths[i], NULL, rotate, (void *) i)){
              printf("ERROR: During thread_create() - number %d\n)", i); exit(-1); 
            }        
            usleep(500000);
          }    
          for(i=0; i<t; i++){ 
            pthread_join(ths[i], NULL); 
            pthread_cond_destroy(&cond[i]);
          }
          kAbs = n;
        }  
        pthread_mutex_destroy(&mutex);
        free(tmp);
            // Rotated array to be printed
        printf("\n\nRotated Array:\n");
        Print();
        printf("--- --- ---\n\n");
        sleep(2);
      } while (1);
      return 0;
    }

  2. #2
    and the hat of int overfl Salem's Avatar
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    Does this differ at all from dwks' last post here?
    Threads\Process
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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