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digitalmars.D.learn - 3 dimension arrays

reply "Andrey" <avraliov gmail.com> writes:
HI guys!!!

Have a problem with 3d array memory allocation in next code:

//////////////////////////////////////////////////////////
class NeuronNet(T, const uint layersNum)
{
	T[]					_inputs;
	T[][layersNum - 2]	_hidden;
	T[]					_outputs;
	T[]					_target;

	//waights [col][row][dimension]
	T[][][layersNum - 1] _waightsArray;

	this(in uint[] nodesArr)
	{
		//values init
		_inputs = new T[nodesArr[0]];
		_outputs = new T[nodesArr[$-1]];

		for(uint j = 0; j < layersNum - 2; j++)
		{
			_hidden[][j] = new T[nodesArr[j + 1]];
		}
		//waights init
		for(uint i = 0; i < layersNum - 1; i++)
		{
			_waightsArray[][][i] = new T[][nodesArr[1+i]];
			for(uint ii = 0; ii < nodesArr[1+i]; ii++)
			{
				_waightsArray[][ii][i] = new T[nodesArr[i]];
			}
		}
	}
}
//////////////////////////////////////////////////////////

debuger shows array range boundary error in line
				_waightsArray[][ii][i] = new T[nodesArr[i]];

Help me please if any one knows
Feb 26 2015
parent reply =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 02/26/2015 12:01 PM, Andrey wrote:> HI guys!!!

 Have a problem with 3d array memory allocation in next code:

 //////////////////////////////////////////////////////////
 class NeuronNet(T, const uint layersNum)
 {
      T[]                    _inputs;
      T[][layersNum - 2]    _hidden;
      T[]                    _outputs;
      T[]                    _target;

      //waights [col][row][dimension]
      T[][][layersNum - 1] _waightsArray;


(Unrelated: That may be a typo if its actually "weights".)


      this(in uint[] nodesArr)
      {
          //values init
          _inputs = new T[nodesArr[0]];
          _outputs = new T[nodesArr[$-1]];

          for(uint j = 0; j < layersNum - 2; j++)


Better:

     foreach (j; 0 .. layersNum - 2)


          {
              _hidden[][j] = new T[nodesArr[j + 1]];


You have extra [] up there. This is equivalent:

              _hidden[j] = new T[nodesArr[j + 1]];

The reason is, _hidden[] means "the entire _hidden slice" anyway. So, 
the empty [] has no meaning at all.


          }
          //waights init
          for(uint i = 0; i < layersNum - 1; i++)
          {
              _waightsArray[][][i] = new T[][nodesArr[1+i]];


Same there:

              _waightsArray[i] = new T[][nodesArr[1+i]];


              for(uint ii = 0; ii < nodesArr[1+i]; ii++)
              {
                  _waightsArray[][ii][i] = new T[nodesArr[i]];


You want to set ii'th element of the i'th element, right? This is the 
right way to do it in D:

     _waightsArray[i][ii] = ...

Unlike C and C++, the array syntax is natural in D. In other words, it 
is not "inside out".

      T[] --> A slice of Ts
      T[][] --> A slice of T slices
      T[][][layersNum - 1] --> A number of those

So, _waightsArray[i] is one of the slices that you've just set in the 
previous for loop.

Ali
Feb 26 2015
parent "Andrey" <avraliov gmail.com> writes:
On Thursday, 26 February 2015 at 23:25:22 UTC, Ali Çehreli wrote:

 On 02/26/2015 12:01 PM, Andrey wrote:> HI guys!!!

 Have a problem with 3d array memory allocation in next code:

 //////////////////////////////////////////////////////////
 class NeuronNet(T, const uint layersNum)
 {
      T[]                    _inputs;
      T[][layersNum - 2]    _hidden;
      T[]                    _outputs;
      T[]                    _target;

      //waights [col][row][dimension]
      T[][][layersNum - 1] _waightsArray;


 (Unrelated: That may be a typo if its actually "weights".)


      this(in uint[] nodesArr)
      {
          //values init
          _inputs = new T[nodesArr[0]];
          _outputs = new T[nodesArr[$-1]];

          for(uint j = 0; j < layersNum - 2; j++)


 Better:

     foreach (j; 0 .. layersNum - 2)


          {
              _hidden[][j] = new T[nodesArr[j + 1]];


 You have extra [] up there. This is equivalent:

              _hidden[j] = new T[nodesArr[j + 1]];

 The reason is, _hidden[] means "the entire _hidden slice" 
 anyway. So, the empty [] has no meaning at all.


          }
          //waights init
          for(uint i = 0; i < layersNum - 1; i++)
          {
              _waightsArray[][][i] = new T[][nodesArr[1+i]];


 Same there:

              _waightsArray[i] = new T[][nodesArr[1+i]];


              for(uint ii = 0; ii < nodesArr[1+i]; ii++)
              {
                  _waightsArray[][ii][i] = new T[nodesArr[i]];


 You want to set ii'th element of the i'th element, right? This 
 is the right way to do it in D:

     _waightsArray[i][ii] = ...

 Unlike C and C++, the array syntax is natural in D. In other 
 words, it is not "inside out".

      T[] --> A slice of Ts
      T[][] --> A slice of T slices
      T[][][layersNum - 1] --> A number of those

 So, _waightsArray[i] is one of the slices that you've just set 
 in the previous for loop.

 Ali


I very much appreciate. The author of D-book respond to me. 
THANKS VERY MUCH!!!!!
Feb 27 2015