Added support for writing gadget files

src/loadGadget.cpp

@@ -273,3 +273,73 @@ SimuData *CosmoTool::loadGadgetMulti(const char *fname, int id, int loadflags, i
 }
 
 
+
+void CosmoTool::writeGadget(const char *fname, SimuData *data, int GadgetFormat)
+{
+  UnformattedWrite *f;
+  int npart[6];
+  float mass[6];
+
+  if (data->Pos[0] == 0 || data->Vel[0] == 0 || data->Id == 0)
+    return;
+
+  f = new UnformattedWrite(fname);
+  if (f == 0)
+    return;
+
+  for (int i = 0; i < 6; i++)
+    {
+      npart[i] = 0;
+      mass[i] = 0;
+    }
+
+  npart[1] = data->NumPart;
+  
+  f->beginCheckpoint();
+  for (int i = 0; i < 6; i++)
+    f->writeInt32(npart[i]);
+  for (int i = 0; i < 6; i++)
+    f->writeReal64(mass[i]);
+
+  f->writeReal64(data->time);
+  f->writeReal64(1/data->time-1);
+  f->writeInt32(0);
+  f->writeInt32(0);
+
+  for (int i = 0; i < 6; i++)
+    f->writeInt32(npart[i]);
+  f->writeInt32(0);
+  f->writeInt32(1);
+  f->writeReal64(data->BoxSize);
+  f->writeReal64(data->Omega_M);
+  f->writeReal64(data->Omega_Lambda);
+  f->writeReal64(data->Hubble);
+  f->endCheckpoint();
+ 
+  f->beginCheckpoint();
+  for(int n = 0; n < data->NumPart; n++) {
+    for (int k = 0; k < 3; k++)
+      f->writeReal32(data->Pos[k][n]);
+  }
+  f->endCheckpoint();
+
+  float velmul = 1.0;
+  if (GadgetFormat == 1)
+    velmul = sqrt(data->time);
+
+  f->beginCheckpoint();
+  for(int n = 0; n < data->NumPart; n++) {
+    for (int k = 0; k < 3; k++)
+      f->writeReal32(data->Vel[k][n]/velmul);
+  }
+  f->endCheckpoint();
+
+  f->beginCheckpoint();
+  for(int n = 0; n < data->NumPart; n++)
+    {
+      f->writeReal32(data->Id[n]);
+    }
+  f->endCheckpoint();
+}
+
+  

src/loadGadget.hpp

@@ -10,6 +10,9 @@ namespace CosmoTool {
 
   SimuData *loadGadgetMulti(const char *fname, int id, int flags, int GadgetFormat = 1);
  
+  // Only single snapshot supported
+  void writeGadget(const char *fname, SimuData *data, int GadgetFormat = 1);
+ 
 };
 
 #endif