MPI

documents/Programmierparadigmen/MPI.tex

@@ -15,7 +15,7 @@ \section{Erste Schritte}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Funktionen}
-\inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/comm-size.c}
+\inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/comm-size.c}\xindex{MPI\_Comm\_size}
 Liefert die Größe des angegebenen Kommunikators; dh. die Anzahl der Prozesse in der Gruppe.
 
 \textbf{Parameter}
@@ -27,7 +27,7 @@ \section{Funktionen}
 \textbf{Beispiel}
 \inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/comm-size-example.c}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\rule{\textwidth}{0.4pt}
+\rule{\textwidth}{0.4pt}\xindex{MPI\_Comm\_rank}
 \inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/comm-rank.c}
 Bestimmt den Rang des rufenden Prozesses innerhalb des Kommunikators.
 
@@ -42,7 +42,44 @@ \section{Funktionen}
 \textbf{Beispiel}
 \inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/comm-rank-example.c}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\rule{\textwidth}{0.4pt}
+\rule{\textwidth}{0.4pt}\xindex{MPI\_Send}
+\inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-send.c}
+Senden einer Nachricht an einen anderen Prozeß innerhalb eines Kommunikators. (Standard-Send)
+
+\textbf{Parameter}
+\begin{itemize}
+    \item \textbf{buf}: Anfangsadresse des Sendepuffers 
+    \item \textbf{count}: Anzahl der Elemente des Sendepuffers (nichtnegativ) 
+    \item \textbf{datatype}: Typ der Elemente des Sendepuffers (handle)
+    \item \textbf{dest}: Rang des Empfängerprozesses in comm (integer)
+    \item \textbf{tag}: message tag zur Unterscheidung verschiedener Nachrichten; 
+Ein Kommunikationsvorgang wird durch ein Tripel (Sender, Empfänger, tag) eindeutig beschrieben. 
+    \item \textbf{comm}: Kommunikator (handle)
+\end{itemize}
+
+\textbf{Beispiel}
+\inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-send-example.c}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\rule{\textwidth}{0.4pt}\xindex{MPI\_Recv}
+\inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-receive.c}
+Empfangen einer Nachricht (blockierend) 
+
+\textbf{Parameter}
+\begin{itemize}
+    \item \textbf{buf}: Anfangsadresse des Empfangspuffers
+    \item \textbf{status}: Status, welcher source und tag angibt (\texttt{MPI\_Status}) 
+    \item \textbf{count}: Anzahl der Elemente im Empfangspuffer (nichtnegativ)
+    \item \textbf{datatype}: Typ der zu empfangenden Elemente (handle)
+    \item \textbf{source}: Rang des Senderprozesses in comm oder \texttt{MPI\_ANY\_SOURCE}
+    \item \textbf{tag}: message tag zur Unterscheidung verschiedener Nachrichten
+                  Ein Kommunikationsvorgang wird durch ein Tripel (Sender, Empfänger, tag) eindeutig beschrieben. Um Nachrichten mit beliebigen tags zu empfangen, benutzt man die Konstante \texttt{MPI\_ANY\_TAG}.
+    \item \textbf{comm}: Kommunikator (handle) 
+\end{itemize}
+
+\textbf{Beispiel}
+\inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-receive-example.c}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\rule{\textwidth}{0.4pt}\xindex{MPI\_Reduce}
 \inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-reduce.c}
 Führt eine globale Operation \textbf{op} aus; der Prozeß \enquote{root} erhält das Resultat.
 
@@ -56,7 +93,7 @@ \section{Funktionen}
     \item \textbf{comm}: Kommunikator (handle)
 \end{itemize}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\rule{\textwidth}{0.4pt}
+\rule{\textwidth}{0.4pt}\xindex{MPI\_Bcast}
 \inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-bcast.c}
 Sendet eine Nachricht vom Prozess \texttt{root} an alle anderen Prozesse des 
 angegebenen Kommunikators.
@@ -70,7 +107,7 @@ \section{Funktionen}
     \item \textbf{comm}: Kommunikator (handle)
 \end{itemize}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\rule{\textwidth}{0.4pt}
+\rule{\textwidth}{0.4pt}\xindex{MPI\_Scatter}
 \inputminted[numbersep=5pt, tabsize=4]{c}{scripts/mpi/mpi-scatter.c}
 Verteilt Daten vom Prozess \texttt{root} unter alle anderen Prozesse in der Gruppe, so daß, soweit möglich, alle Prozesse gleich große Anteile erhalten.
 

documents/Programmierparadigmen/scripts/mpi/for-example.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <mpi.h>
+int main (int argc, char** args) {
+    int size, i;
+    int myrank;
+    MPI_Init(&argc, &args);
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+    MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
+
+    for (i=0; i<size; i++) {
+        MPI_Barrier(MPI_COMM_WORLD);
+        if (i == myrank) {
+            printf("Hello World, I have rank %d out of %d.\n",
+                myrank, size);
+        }
+    }
+
+    MPI_Finalize();
+    return 0;
+}

documents/Programmierparadigmen/scripts/mpi/mpi-receive-example.c

@@ -0,0 +1,18 @@
+#include "mpi.h"
+
+int           msglen, again=1;
+void          *buf;
+MPI_Datatype  datatype
+MPI_Comm      comm;
+MPI_Status    status;
+
+...  
+while (again) {
+MPI_Probe(ROOT, MPI_ANY_TAG, comm, &status);
+    MPI_Get_count(&status, datatype, &msglen);
+buf=malloc(msglen*sizeof(int));
+MPI_Recv(buf, msglen, datatype, status.MPI_SOURCE, 
+         status.MPI_TAG, comm, &status);
+    ...
+}
+...

documents/Programmierparadigmen/scripts/mpi/mpi-receive.c

@@ -0,0 +1,3 @@
+int MPI_Recv(void *buf, int count, 
+             MPI_Datatype datatype, int source, int tag,
+             MPI_Comm comm, MPI_Status *status)

documents/Programmierparadigmen/scripts/mpi/mpi-send-example.c

@@ -0,0 +1,18 @@
+#include "mpi.h"
+...
+int signal, i, numprogs, me;
+MPI_Status stat;
+MPI_Comm_rank(MPI_COMM_WORLD, &me);
+MPI_Comm_size(MPI_COMM_WORLD, 
+             &numprocs);
+if (me==ROOT) {
+    ... 
+for (i=1; i<numprocs; i++) {
+    MPI_Send(&signal, 1, MPI_INT, i, 0, MPI_COMM_WORLD);
+}
+... 
+else {
+    MPI_Recv(&sig, 1, MPI_INT, ROOT, MPI_ANY_TAG,
+             MPI_COMM_WORLD, &stat);
+    ... 
+}

documents/Programmierparadigmen/scripts/mpi/mpi-send.c

@@ -0,0 +1,3 @@
+int MPI_Send(void *buf, int count, 
+             MPI_Datatype datatype, int dest, 
+             int tag, MPI_Comm comm)