vector of vector to double pointers?

My Layer class is:

Layer::Layer(int _nOutput, vector<double> **_iVector, vector<double> **_oVector, int _actFuncType)
{
....
}

I tested a little and I think you need to show what you do with _oVector inside Layer::Layer. There doesn't seem to be anything wrong with the calls you do.

well.. hope this is not too long to paste here:

// Layer.h

#include <vector>
using namespace std;

#ifndef _LAYER_H_
#define _LAYER_H_

class Layer
{
public:
        int nInput, nOutput;
        double **weights;
        vector<double> **iVector, **oVector;
        double (*actFuncPtr)(double);

        Layer(int, vector<double> **, vector<double> **, int =0);
        ~Layer();
        static double sigmoidalActFunc(double);
        static double emptyActFunc(double);
        void run(int =1);
};

#endif /*_LAYER_H_*/


// Layer.cpp

#include <iostream>
#include <math.h>
#include "Layer.h"
using namespace std;

Layer::Layer(int _nOutput, vector<double> **_iVector, vector<double> **_oVector, int _actFuncType)
{
        if (*_oVector != NULL && _nOutput != (int)(*_oVector)->size()) {
                cerr << "The size of output vector mismatch\n";
                exit(EXIT_FAILURE);
        }

        nInput      = (*_iVector)->size();
        nOutput     = _nOutput;
        iVector     = _iVector;
        oVector     = _oVector;

        switch (_actFuncType) {
                case 0 :
                        actFuncPtr = &sigmoidalActFunc;
                        break;
                case 1 :
                        actFuncPtr = &emptyActFunc;
                        break;
                default:
                        actFuncPtr = &emptyActFunc;
                        break;
        }

        if (*oVector == NULL) {
                *oVector = new vector<double>(nOutput, 0);
                _oVector = oVector;
        }

        double *tWeights = (double *) malloc(nInput * nOutput * sizeof(double));
        int i;

        if (tWeights == NULL) {
                cerr << "Unable to allocate memory\n";
                exit(EXIT_FAILURE);
        }

        for (i = 0; i < nInput * nOutput; ++i) {
                *(tWeights + i) = (double)rand()/RAND_MAX;
        }

        weights = (double **) malloc(nInput * sizeof(double *));
        if (weights == NULL) {
                cerr << "Unable to allocate memory\n";
                exit(EXIT_FAILURE);
        }

        for (i = 0; i < nInput; ++i) {
                weights[i] = tWeights + (i * nOutput);
        }
}

Layer::~Layer()
{
        free(*weights);
}

double Layer::sigmoidalActFunc(double _input)
{
        return (double)1/(1+exp(-_input));
}

double Layer::emptyActFunc(double _input)
{
        return _input;
}

void Layer::run(int _step)
{
        int step, i, j;

        for (step = 0; step < _step; ++step) {
                for (i = 0; i < nOutput; ++i) {
                        for (j = 0; j < nInput; ++j) {
                                (*oVector)->at(i) += (*iVector)->at(j) * weights[j][i];
                        }
                        (*oVector)->at(i) = actFuncPtr((*oVector)->at(i));
                }
        }
}

if (*oVector == NULL) {
                *_oVector = new vector<double>(nOutput, 0);
                oVector = _oVector;
}

If you don't see the difference, let me know...

Hi khun,

nope, still getting the same output.

Hi guys,

I use C most of the time hence I am not really good in C++ code/practises.  I know that the class Layer does not practise good C++.  However, the problem that I am facing is that from the main(), i==0, i==1 and i==2 behaved differently.  khun explained that the h_output would be reallocated in memory once a new element is pushed into it, that explain why I am getting the different, since arrays and static variables are not move around memory.

The suggestion that using vector<vector<double> *> h_output(2); works but when I need to grow the h_output, I will face the same problem (I need the capability for doing some Back Prop Thru Time - keeping all the time layers).

Anyway, I understand the problem now and I think that Alex has some good suggestion that I should really try to recode my class.

Thanks for help..

Oopps... I mean to split the point khan for accepted answer and Alex for assited answer.  jkr.. little help?