added default value: p in second line of METAARH format

AMDiS/src/io/Arh2Reader.cc

@@ -311,6 +311,8 @@ namespace AMDiS { namespace io {
       file >> arhPrefix;
       int nProc;
       file >> nProc;
+      
+      MSG("found nProc %d in file %s \n",nProc,filename.c_str());
 
       // Maps to each macro element index the arh file index it is stored in.
       for (int i = 0; i < nProc; i++) {

AMDiS/src/io/Arh2Writer.cc

@@ -94,7 +94,7 @@ namespace AMDiS { namespace io {
 	ofstream file;
 	file.open(metaFilename.c_str());
 	file << "METAARH\n";
-	file << "" << "\n";
+	file << "p" << "\n";	//edit 150420: just write something
 	file << mpiSize << "\n";
 	for (int i = 0; i < mpiSize; i++) {
 	  file << i << " " << overallData[i].size() << "\n";