Hi:

I need to write a program that essentially needs to mane a list of a list of a list (that's right 3 times) of a certain class I created. I was having some efficiency problems so I decided to change all of the accesses to the structure form structure[i][j][k] to using the .at() function. I wrote a little code just to test this:

This is the Class named Tile.h
Qt Code: 
  1. class Tile
  2. {
  3. public:
  4.     Tile(qreal p, QList<quint16>);
  5.     Tile();
  6.  
  7.     //Definition of basic operations
  8.     bool operator == (Tile t);
  9.  
  10.     //Definition of sets and getters.
  11.     QList<quint16> Indexes(){return indexes;}
  12.     qreal param(){return parameter;}
  13.     void setParam(qreal p){parameter = p;}
  14.     void setIndexes(QList<quint16> ind){indexes = ind;}
  15.  
  16.     //Function use Mainly for Debugging
  17.     QString toString();
  18.  
  19.     virtual ~Tile();
  20.  
  21. private:
  22.     qreal parameter;
  23.     QList<quint16> indexes;
  24. };
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And the Tile.cpp
Qt Code: 
  1. Tile::Tile(qreal p, QList<quint16> ind){
  2.     indexes = ind;
  3.     parameter = p;
  4.     elegibility = 0;
  5. }
  6.  
  7. Tile::Tile(){
  8.     parameter = 0;
  9. }
  10.  
  11. /****************Operators**************************/
  12. bool Tile::operator == (Tile t){
  13.     QList<quint16> comp = t.Indexes();
  14.     bool res = true;
  15.     for (int i = 0; i < comp.size(); i++){
  16.         if (comp.at(i) != indexes.at(i)){
  17.             res = false;
  18.             break;
  19.         }
  20.     }
  21.     return res;
  22. }
  23.  
  24. /***********toString******************/
  25. QString Tile::toString(){
  26.     QString ws = "";
  27.     for (int i = 0; i < indexes.size(); i++){
  28.         ws = ws + " " + QString::number(indexes.at(i));
  29.     }
  30.  
  31.     if(indexes.size() == 0){
  32.         ws = "Nothing to show: Value is: " + QString::number(parameter);
  33.     }
  34.  
  35.     return ws;
  36. }
  37.  
  38. Tile::~Tile(){
  39. }
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Then I wrote this code in a constructor just to test using this
Qt Code: 
  1. int Im = 5;
  2.     int Jm = 10;
  3.     int Km = 6000;
  4.     for (int i = 0; i < Im; i++){
  5.         QVector < QVector<Tile> > temp2;
  6.         for(int j = 0; j < Jm; j++){
  7.             QVector<Tile> temp;
  8.             for (int k = 0; k < Km; k++){
  9.                 QList<quint16> ind;
  10.                 ind << k;
  11.                 Tile t(0,ind);
  12.                 temp << t;
  13.             }
  14.             temp2 << temp;
  15.         }
  16.         test << temp2;
  17.     }
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Where test is defined by:
Qt Code: 
  1. QVector < QVector< QVector<Tile> > > test;
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So then I write this line in a button action just to see if it would compile
Qt Code: 
  1. test.at(2).at(5).at(3940).setParam(test.at(2).at(5).at(3940).param() + 15.0);
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And it doesn't and I get these two errors
passing ‘const Tile’ as ‘this’ argument of ‘qreal Tile:aram()’ discards qualifiers
passing ‘const Tile’ as ‘this’ argument of ‘void Tile::setParam(qreal)’ discards qualifiers

So I change it to this in order for it to work
Qt Code: 
  1. test[2][5][3940].setParam(test[2][5][3940].param() + 15.0);
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And this works but according to the Qt documentation [] is a lot more inefficient that at(). So I want it to change it to see if my algorithm would go a bit faster.

So my question is are there any suggestion on how to make this a bit more efficient to see if I can shave off some minutes to the my algortihms runs or am I just stuck with the slow program. Or maybe on how could I manage a list of a list of a list of classes in a more efficient way.

Thanks for any help