From 13f6786a139e44db8bb2009b0160eea906b91ead Mon Sep 17 00:00:00 2001
From: norangebit <git@norangeb.it>
Date: Fri, 19 Mar 2021 18:50:59 +0100
Subject: [PATCH] general fixes

---
 main.c | 48 ++++++++++++++++++++++--------------------------
 1 file changed, 22 insertions(+), 26 deletions(-)

diff --git a/main.c b/main.c
index db3f2f6..fd791a5 100644
--- a/main.c
+++ b/main.c
@@ -18,8 +18,10 @@ int main() {
     int rank, size, private_text_len, text_len, pattern_len;
     int *text_piece;
     int *match_numbers;
+    int *total_matches;
+    int total_match_number;
     int *displacements;
-    int remain;
+    int remain = 0;
     char *pattern, *text;
 
     MPI_Init(NULL, NULL);
@@ -57,7 +59,13 @@ int main() {
                  MPI_COMM_WORLD);
     private_text[private_text_len] = '\0';
 
+    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);
+
     printf("%d -> input: %s\n", rank, private_text);
+    printf("%d -> text len:%d\n", rank, private_text_len);
 
     MPI_Bcast(&pattern_len, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
 
@@ -85,7 +93,9 @@ int main() {
             find_end(residue, pattern, private_text, &matches, &match_number);
     }
 
-    int shift = rank * private_text_len;
+    print_array(matches, match_number);
+
+    int shift = rank * (private_text_len - remain);
     apply_shift(shift, matches, match_number);
 
     printf("%d -> result number: %d\n", rank, match_number);
@@ -97,41 +107,27 @@ int main() {
     MPI_Gather(&match_number, 1, MPI_INT, match_numbers, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
 
     if (rank == MASTER) {
-        match_number = sum_array(match_numbers, size);
-        matches = (int *) realloc(matches, sizeof(int) * match_number);
+        total_match_number = sum_array(match_numbers, size);
 
-        int offset = 0;
-        for (int i = 0; i < size; ++i) {
-            if (i == MASTER) {
-                offset += match_numbers[i];
-                continue;
-            }
-
-            MPI_Recv(matches + offset, match_numbers[i], MPI_INT, i, DEFAULT_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
-            offset += match_numbers[i];
+        total_matches = (int *) malloc(sizeof(int) * total_match_number);
+        displacements[0] = 0;
+        for (int i = 0; i < size - 1; ++i) {
+            displacements[i + 1] = displacements[i] + match_numbers[i];
         }
-    } else {
-        MPI_Send(matches, match_number, MPI_INT, MASTER, DEFAULT_TAG, MPI_COMM_WORLD);
     }
 
+    MPI_Gatherv(matches, match_number, MPI_INT, total_matches, match_numbers, displacements, MPI_INT, MASTER,
+                MPI_COMM_WORLD);
+
     MPI_Finalize();
 
     if (rank == MASTER) {
-        printf("total matches: %d\n", match_number);
+        printf("total matches: %d\n", total_match_number);
         printf("matches index: ");
-        print_array(matches, match_number);
+        print_array(total_matches, total_match_number);
     }
 }
 
-char *read_text(int *len) {
-    return read_file("data/text.txt", len);
-}
-
-char *read_pattern() {
-    // TODO
-    return "mamma";
-}
-
 void find_end(int residue, char *pattern, char *text, int **matches, int *match_number) {
     int pattern_index = residue;
     int text_index = 0;