how can i save 2D array of double to a file?

[Marco M]

i tried to use FileStream Class but it only supports writing byte[] not even byte[,].. anyone has a clue ? thanx shakooosh

[ian mariano]

Suppose wr is your BinaryWriter, your multidimensional (rectangular) array, theArray is 2D. Store and write the dimensions out thus (C#):

int mupper = theArray.GetUpperBound(0);
int nupper = theArray.GetUpperBound(1);
 
ws.Write(mupper);
ws.Write(nupper);

Then write out the bytes:

for (int i = 0; i < mupper; i++)
{
   for (int j = 0; j < nupper; i++)
      wr.Write(theArray[i, j]);
}

To read it back in, you do the reverse:

//  rdr is a BinaryReader
int mupper = rdr.ReadInt32();
int nupper = rdr.ReadInt32();
byte[,] theArray = new byte[mupper, nupper];
 
for (int i = 0; i < mupper; i++)
{
   for (int j = 0; j < nupper; i++)
      theArray[i, j] = rdr.ReadByte();
}

The problem is that this is not that efficient. If, however, you used a jagged array (actually, the secondary array never differs in length so for all purposes it's still rectangular not jagged,) you can define theArray 2d, m,n like this:

byte[][]  theArray = new byte[m][];
 
for (int i = 0; i < theArray.Length; i++)
   theArray[i] = new byte[n];

You access the byte at x, y thus: theArray[x][y] Saving is a lot more efficient using a jagged array:

//  wr is our BinaryWriter
wr.Write(theArray.Length);  //  m
wr.Write(theArray[0].Length);  //  n
  
for (int i = 0; i < theArray.Length; i++)
   wr.Write(theArray[i]);

Reading back in is also more efficient:

//  rdr is a BinaryReader
int m = rdr.ReadInt32();
int n = rdr.ReadInt32();
byte[][] theArray = new byte[m][];
 
for (int i = 0; i < theArray.Length; i++)
   theArray[i] = rdr.ReadBytes(n);

The jagged array code will also save non-rectangular arrays without modification.

Ian Mariano - http://www.ian-space.com/
"We are all wave equations in the information matrix of the universe" - me

[Marco M]

the problem is the array is not an array of bytes.. it's an array of type double, declared this way: " double arr[,] x; " and the method "Write()" takes array of bytes as an argument... thanx for replying shakoosh

[ian mariano]

Using a jagged array instead of a rectangular one as above will do the trick. You just use double[][] x instead of double[,] x. See above. The code that would change would be the array initializers and accessors. If this is too much retrofit for the code, use the rectangular dual for loop method above.

Ian Mariano - http://www.ian-space.com/
"We are all wave equations in the information matrix of the universe" - me

[Roman Rodov]

you need to devise your own save/load algorithm for example for ( int i = myArray.GetLowerBound(0); i <= myArray.GetUpperBound(0); i++ ) for ( int j = myArray.GetLowerBound(1); j <= myArray.GetUpperBound(1); j++ ) myFileStream.WriteByte(byte.Parse(myArray.GetValue( i, j ).ToString()) ); don't take my word on the syntax .... but you get the idea