# Robust-first Computing Wiki

dev:data_output

## Getting Statistical Data Out of Your Simulation

You have a simulation up and running, but how do you get the statistical data you need ouput to a file? Below you will find some code provided by Professor Ackley that will allow you to do so.

There are two files that need to be modified:

 1. /src/drivers/mfmc/src/main.cpp
2. /src/sim/include/AbstractDriver.h

### main.cpp

To edit the main.cpp file, paste the following code into the Private section of the file:

const char* GetSimDirPathTemporary(const char* format, ...) const
{
static OverflowableCharBufferByteSink<500> buf;
buf.Reset();
buf.Printf("%s",this->GetSimulationBasePath());
va_list ap;
va_start(ap, format);
buf.Vprintf(format, ap);
if (buf.HasOverflowed())
{
FAIL(OUT_OF_ROOM);
}
return buf.GetZString();
}

and

typedef typename CC::PARAM_CONFIG P;
typedef typename CC::ATOM_TYPE T;

Then paste the following in the public section of main.cpp:

virtual void DoEpochEvents(Grid<GC>& grid, u32 epochs, u32 epochAEPS)
{
u32 H = Grid<GC>::GetHeight();
u32 W = Grid<GC>::GetWidth();

u32 emptyCount = 0;
for (u32 y = 0; y < H; ++y)
{
for (u32 x = 0; x < W; ++x)
{
Tile<CC> & tile = grid.GetTile(SPoint(x,y));
for (u32 x = 0; x < P::TILE_WIDTH; ++x)
{
for (u32 y = 0; y < P::TILE_WIDTH; ++y)
{
const SPoint pt(x, y);
if(Tile<CC>::IsInCache(pt))
{
continue;
}
const T * atom = tile.GetAtom(x,y);

//<<<TODO>>> This is where you grab the data from your element. Modify accordingly.
if (atom->GetType() == Element_Empty<CC>::THE_INSTANCE.GetType())
++emptyCount;
}
}
}
}

//<<<TODO>>> replace FILE_NAME with the file name of your choice
const char* path = GetSimDirPathTemporary("tbd/FILE_NAME.dat");
FILE* fp = fopen(path, "a");

//<<<TODO>>> This is where you output the specific data you need. Modify accordingly.
fprintf(fp, "%d %d %d\n",epochs, epochAEPS, emptyCount);
fclose(fp);
// Remember to let the parent run too!
Super::DoEpochEvents(grid, epochs, epochAEPS);
}

Please note: There are 3 TODO tags in the above snippet. These are where you'll need to modify the code to suit your needs.

### AbstractDriver.h

Now we need to do a small modifcation to the AbstractDriver.h file. Paste the following code into the public section:

const char * GetSimulationBasePath() const
{
return &m_simDirBasePath[0];
}

And that's it! Happy scienceing.