Each file read own portion

src/parallel.c

@@ -14,12 +14,6 @@
 
 void find_end(int, char *, char *, int **, int *);
 
-void initialize(char *);
-
-void distribute_text();
-
-void distribute_pattern();
-
 void search_for_splitted_pattern(int *residue, int *match_number, int **matches);
 
 void calculate_absolute_indices(int match_number, int *matches);
@@ -49,23 +43,16 @@ int main(int argc, char **argv) {
 #ifdef TIME
     long_long start_time = PAPI_get_real_usec();
 #endif
-    if (rank == MASTER) {
+
     char *text_file_path = get_text_file(argc, argv);
-        initialize(text_file_path);
+    private_text = read_file_portion(text_file_path, size, rank, &private_text_len, &remain);
-    }
+    pattern = read_file("data/pattern.txt", &pattern_len);
-
-    distribute_text();
-
-    if (rank == MASTER)
-        free(text);
 
 #ifdef LOG
     printf("%d -> input: %s\n", rank, private_text);
     printf("%d -> text len: %d\n", rank, private_text_len);
 #endif
 
-    distribute_pattern();
-
     // create and build lps array
     int lps[pattern_len];
     create_lps(pattern, pattern_len, lps);
@@ -80,7 +67,7 @@ int main(int argc, char **argv) {
 
     search_for_splitted_pattern(&residue, &match_number, &matches);
 
-    free(private_text);
+    //free(private_text);
 
     calculate_absolute_indices(match_number, matches);
 
@@ -116,7 +103,6 @@ void find_end(int residue, char *pattern, char *text, int **matches, int *match_
     int text_len = strlen(text);
     int pattern_len = strlen(pattern);
 
-    // TODO: match splitted on 3+ node
     if (pattern_len - residue > text_len) return;
 
     while (pattern_index < pattern_len && pattern[pattern_index] == text[text_index]) {
@@ -131,67 +117,6 @@ void find_end(int residue, char *pattern, char *text, int **matches, int *match_
     (*matches)[*match_number - 1] = -residue;
 }
 
-void initialize(char *text_file_path) {
-    text = read_file(text_file_path, &text_len);
-    pattern = read_file("data/pattern.txt", &pattern_len);
-
-    //printf("text: %s\n", text);
-    //printf("pattern: %s\n", pattern);
-
-    private_text_len = text_len / size;
-    remain = text_len % size;
-
-    if (pattern_len > private_text_len)
-        MPI_Abort(MPI_COMM_WORLD, 1);
-
-    text_piece = (int *) malloc(sizeof(int) * size);
-    displacements = (int *) malloc(sizeof(int) * size);
-
-    displacements[0] = 0;
-    for (int i = 0; i < size - 1; ++i) {
-        text_piece[i] = private_text_len;
-        displacements[i + 1] = displacements[i] + private_text_len;
-    }
-
-    text_piece[size - 1] = private_text_len + remain;
-}
-
-void distribute_text() {
-    // distribution of the length of the text portion to each process
-    MPI_Scatter(text_piece, 1, MPI_INT, &private_text_len, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
-
-    // allocation of space for text
-    private_text = (char *) malloc(sizeof(char) * (private_text_len + 1));
-
-    // distribution of the text portion to each process
-    // scatterv is necessary because the last process receives a larger portion of text in case it is not perfectly divisible.
-    MPI_Scatterv(
-            text,
-            text_piece,
-            displacements,
-            MPI_CHAR,
-            private_text,
-            private_text_len,
-            MPI_CHAR, MASTER,
-            MPI_COMM_WORLD
-    );
-    private_text[private_text_len] = '\0';
-}
-
-void distribute_pattern() {
-    // distribution of the length of the pattern to each process
-    MPI_Bcast(&pattern_len, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
-
-    // allocation of space for the pattern
-    // the master has already done so previously
-    if (rank != MASTER) {
-        pattern = (char *) malloc(sizeof(char) * (pattern_len + 1));
-    }
-
-    // distribution of the pattern to each process
-    MPI_Bcast(pattern, pattern_len + 1, MPI_CHAR, MASTER, MPI_COMM_WORLD);
-}
-
 void search_for_splitted_pattern(int *residue, int *match_number, int **matches) {
     // send the residue to the next process
     if (rank + 1 != size) {
@@ -209,13 +134,6 @@ void search_for_splitted_pattern(int *residue, int *match_number, int **matches)
 }
 
 void calculate_absolute_indices(int match_number, int *matches) {
-    // sending the remain to the last process
-    // this is necessary for the calculation of shift amount
-    if (rank == MASTER)
-        MPI_Send(&remain, 1, MPI_INT, size - 1, DEFAULT_TAG, MPI_COMM_WORLD);
-    else if (rank == size - 1)
-        MPI_Recv(&remain, 1, MPI_INT, MASTER, DEFAULT_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
-
     // transformation of match indices from relative to absolute position.
     int shift = rank * (private_text_len - remain); // the rest is zero for all but the last process
     apply_shift(shift, matches, match_number);
@@ -235,6 +153,7 @@ void collect_results(int *match_number, int *matches) {
         total_match_number = sum_array(match_numbers, size);
         total_matches = (int *) malloc(sizeof(int) * total_match_number);
 
+        displacements = (int *) malloc(sizeof(int) * size);
         displacements[0] = 0;
         for (int i = 0; i < size - 1; ++i) {
             displacements[i + 1] = displacements[i] + match_numbers[i];

src/util.c

@@ -54,7 +54,7 @@ char *read_file(char *filepath, int *len) {
     return content;
 }
 
-char *read_file_portion(char *filepath, int size, int rank, int *portion_len) {
+char *read_file_portion(char *filepath, int size, int rank, int *portion_len, int *remain) {
     FILE *f = fopen(filepath, "r");
     fseek(f, 0, SEEK_END);
     int total_len = ftell(f) - 1;
@@ -63,8 +63,10 @@ char *read_file_portion(char *filepath, int size, int rank, int *portion_len) {
 
     int start_point = rank * len;
     int end_point = start_point + len;
+
     if (rank + 1 == size)
-        end_point += total_len % size;
+        *remain = total_len % size;
+    end_point += *remain;
 
     *portion_len = end_point - start_point;
     char *content = (char *) malloc(sizeof(char) * (*portion_len));
@@ -75,5 +77,5 @@ char *read_file_portion(char *filepath, int size, int rank, int *portion_len) {
 
     content[*portion_len] = '\0';
 
-    return NULL;
+    return content;
 }

src/util.h

@@ -11,6 +11,6 @@ int sum_array(int *, int);
 
 char *get_text_file(int argc, char **argv);
 
-char *read_file_portion(char *filepath, int size, int rank, int *portion_len);
+char *read_file_portion(char *filepath, int size, int rank, int *portion_len, int *remain);
 
 #endif //KMP_UTIL_H