diff --git a/cs677/hw4/src/Makefile b/cs677/hw4/src/Makefile
new file mode 100644
index 0000000..06eb261
--- /dev/null
+++ b/cs677/hw4/src/Makefile
@@ -0,0 +1,11 @@
+
+FILE := transpose
+TARGET := $(FILE)
+
+all: $(TARGET)
+
+$(TARGET): $(FILE).cc
+	mpiCC -o $@ $<
+
+clean:
+	-rm -f *.o *~ $(TARGET)
diff --git a/cs677/hw4/src/transpose.cc b/cs677/hw4/src/transpose.cc
new file mode 100644
index 0000000..3e8e109
--- /dev/null
+++ b/cs677/hw4/src/transpose.cc
@@ -0,0 +1,109 @@
+
+#include <iostream>
+#include <sys/time.h>
+#include <unistd.h>     /* gethostname() */
+#include <stdlib.h>     /* rand() */
+#include <mpi.h>
+using namespace std;
+
+#define TRIALS 100
+
+double sendAndTime(int length);
+void receive(int length);
+
+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];
+
+    MPI_Init(&argc, &argv);
+    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
+
+    if (my_rank == 0)
+    {
+        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)
+        {
+            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;
+            }
+        }
+        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);
+    }
+}