From de4d4a996878776665b955bc17229a539ee20cf2 Mon Sep 17 00:00:00 2001
From: josh <josh@45c1a28c-8058-47b2-ae61-ca45b979098e>
Date: Sat, 22 Nov 2008 23:35:51 +0000
Subject: [PATCH] added taskAllocate()

git-svn-id: svn://anubis/gvsu@242 45c1a28c-8058-47b2-ae61-ca45b979098e
---
 cs677/hw4/src/transpose.cc | 119 +++++++++++--------------------------
 1 file changed, 35 insertions(+), 84 deletions(-)

diff --git a/cs677/hw4/src/transpose.cc b/cs677/hw4/src/transpose.cc
index 3e8e109..a0d0093 100644
--- a/cs677/hw4/src/transpose.cc
+++ b/cs677/hw4/src/transpose.cc
@@ -6,104 +6,55 @@
 #include <mpi.h>
 using namespace std;
 
-#define TRIALS 100
-
-double sendAndTime(int length);
-void receive(int length);
+/*
+ * taskAllocate() will divide a set of total_tasks tasks into
+ * total_workers groups, as evenly as possible
+ * Parameters:
+ *   total_tasks   : IN  : the total number of tasks to divide up
+ *   total_workers : IN  : the total number of workers to allocate tasks to (>0)
+ *   this_id       : IN  : the id (0-based) of the task calling us for work
+ *   first_task_id : OUT : the id (0-based) of the first task for this worker
+ *   num           : OUT : the number of tasks assigned to this worker
+ */
+inline void taskAllocate(int total_tasks, int total_workers, int this_id,
+                         int * first_task_id, int * num)
+{
+    int l_num;
+    int leftovers = total_tasks % total_workers; /* num of "leftover" tasks */
+    if (this_id < leftovers)
+    {
+        l_num = total_tasks / total_workers + 1; /* do one of the leftovers */
+        *first_task_id = l_num * this_id;
+    }
+    else
+    {
+        l_num = total_tasks / total_workers;
+        *first_task_id = l_num * this_id + leftovers;
+    }
+    *num = l_num;
+}
 
 int main(int argc, char * argv[])
 {
     int my_rank;
-    double max_bytes_per_sec = 0.0;
-    int max_bps_pkt_size = 0;
-    char hostname[256];
+    int comm_size;
+    int matrix_size = 100;
 
     MPI_Init(&argc, &argv);
     MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &comm_size);
 
-    if (my_rank == 0)
+    for (int i = 0; i < argc; i++)
     {
-        MPI_Recv(&hostname[0], 256, MPI_CHAR, MPI_ANY_SOURCE,
-            MPI_ANY_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
-        cout << "Remote host name: " << hostname << endl;
-    }
-    else
-    {
-        gethostname(&hostname[0], 255);
-        MPI_Send(&hostname[0], 256, MPI_CHAR, 0, 42, MPI_COMM_WORLD);
-    }
-
-    for (int length = 100; length < 100000; length += 100)
-    {
-        if (my_rank == 0)
+        if (!strncmp(argv[i], "-s", 2))
         {
-            cout << "Testing packet length " << length << endl;
-            double rtt = sendAndTime(length);
-            double bytes_per_sec = (length * TRIALS) / rtt;
-            if (bytes_per_sec > max_bytes_per_sec)
-            {
-                max_bps_pkt_size = length;
-                max_bytes_per_sec = bytes_per_sec;
-            }
+            matrix_size = atoi(strlen(argv[i]) > 2
+                               ? argv[i] + 2
+                               : argv[++i]);
         }
-        else
-        {
-            receive(length);
-        }
-    }
-
-    if (my_rank == 0)
-    {
-        cout << "Maximum bytes per second (round trip) was " << max_bytes_per_sec << endl;
-        cout << "This occurred with a packet size of " << max_bps_pkt_size << endl;
-    }
-    else
-    {
-        cout << "Slave exiting." << endl;
     }
 
     MPI_Finalize();
 
     return 0;
 }
-
-double sendAndTime(int length)
-{
-    char buff[length];
-    for (int i = 0; i < length; i++)
-    {
-        buff[i] = rand() & 0xFF;
-    }
-
-    struct timeval before, after;
-    gettimeofday(&before, NULL);        /* Start timing */
-
-    for (int i = 0; i < TRIALS; i++)
-    {
-        int ret = MPI_Send(&buff, length, MPI_CHAR, 0, 42, MPI_COMM_WORLD);
-//        cout << "MPI_Send() returned " << ret << endl;
-
-        MPI_Recv(&buff, length, MPI_CHAR,
-            MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
-    }
-
-    gettimeofday(&after, NULL);         /* Stop timing */
-
-    double time_before = before.tv_sec + before.tv_usec / 1000000.0;
-    double time_after = after.tv_sec + after.tv_usec / 1000000.0;
-    double diff = time_after - time_before;
-    return diff;
-}
-
-void receive(int length)
-{
-    char buff[length];
-
-    for (int i = 0; i < TRIALS; i++)
-    {
-        MPI_Recv(&buff, length, MPI_CHAR,
-            MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
-
-        MPI_Send(&buff, length, MPI_CHAR, 0, 42, MPI_COMM_WORLD);
-    }
-}