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Arrays -HELP!!!!!!!

Naf Rash
Ranch Hand

Joined: Feb 19, 2004
Posts: 85
Is there any way of returning an array?
I have created an array that holds a series of numbers. However, i need to use this in another method which basically gets the matrix and returns it so that it can be retrieved by another class. Can this be done? I know that to an array can be passed to another method but my issue is with resepct to actually returning it so that it can be manipulated later on.
I am enclosing some code so that you may understand where my problems lay. The errors that I have so far are:
The method getMatrix() in the type distances is not applicable for the arguments (double[][])
Syntax error on keyword "double"; "interface", "class" expected - this is with respect to the actual method getMatrix.

public double[][] manhattan() {
theSum =new int[theCount];
sum = new int [theRowCount][theCount];
/* Comparing each record attribute with the next record. The sum stores the value of the
* differences between records (based on single attributes). The first for stmt looks at
* one row at a time- the second for stmt the compares this row to all the other rows.
* For every row comparison all the attributes are considered. NOTE: the second for stmt
* starts at 2 so that the second row is considered (the first row is dealt with in the
* first for stmt).*/
for (int i=1; i<theRowCount; ++i){
for (int all = 2; all<theRowCount; ++all){
for (int k=1; k<theCount; ++k)//attributes
/* Carry out the calculations to work out the manhattan distance. If the attribute value being
* considered of type int then an exception occurrs and is caught in the catch clause- if the 2
* values differ then the distace is equal to 1 else it is equal to 0.*/
try{
for (int c=1; c<theCount; ++c){
theSum[c]=(sum[k] - sum[all][k]);
}
/*Add all the attribute differences together and then square them. Stores the resulting values
* in an array. */
for (int ts=0; ts<theSum.length-1; ++ts){
distance = distance + theSum [ts];
}
//check to see if the result of the calculation is negative. If so, make it positive.
if (distance<0){
distance = distance*distance;
}
}
catch (NumberFormatException nfe){
if (sum[k] == sum[all][k]){
distance = 0;
}
else if (sum[k] == sum[all][k]){
distance =1;
}
}//end catch

/*Devise the matrix. For the tuples being considered ther manhattan distance is entered in the
* corresponding element of the array.This produces a matrix with the same number of column as rows.
* The size of the matrix changes since it stores some calculations that
* have been carried out on database rows. As a result the number of rows
* that the database has is called for and this determines the size of the
* matrix.*/
int row1= theRowCount, row2= theCount;
double [][] distanceMatrix;
distanceMatrix= new double [row1][row2];
for (i=1;i<row1; ++i){
for (all = 1; all<row2; ++row2)
distanceMatrix[all] =distance;
getMatrix(distanceMatrix);/*The distance matrix is passed call-by-refernce*/
//return distanceMatrix;//[all];
}
}
}

}
public double getMatrix(theDistanceMatrix[][]) {
return theDistanceMatrix[j];
}
Ben Wood
Ranch Hand

Joined: Aug 14, 2001
Posts: 342
Hi.
One potential problem I can see here...

there seems to be some difference between what you are supposed to be returning from this method, and what is actually being returned. I think all of the following modified versions should work, but you will have to chose which is the one you actually need!


SCJP 1.4, www.gsi3d.org.uk
Joseph Kampf
Greenhorn

Joined: Mar 04, 2004
Posts: 26
Here is a version that should compile. (I don't have one of the classes you are using.) But you will get some errors about loss of precision.
There were many errors in this. I suggest you use an IDE for syntax checking such as Eclipse. You were missing matching parens, brackets, semicolons, you mis capilized and misspelled some of your variable names.
------------------------------
public class Clusteringclass {
distances dist = new distances();
double theRow = 1;
double theCoulmn =0;
double newRow = 1;

public Clusteringclass(){
dist.getMatrix();
}
private void obtainClusters(double distanceMatrix[][])
{
for (int i=0;i<distanceMatrix.length; ++i){
for (int all = 1; all<distanceMatrix.length; ++all){
for (double checkDistanceVal = 100; (checkDistanceVal > distanceMatrix[i][all]) && (distanceMatrix[i][all] !=0)
{
checkDistanceVal = distanceMatrix[i][all];/*This will hold the final value ie, the value with the smallest distance.*/
double row = i;
double column = all;/*These assignments ensure that the corresponding row and column numbers are stored for the
shortest value.*/
}
}
}
}

public double[][] addElement(double[][] distanceMatrix, double row, double column ){
double[][] newArray = new double [distanceMatrix.length - 1][distanceMatrix.length - 1];/*Creates a brand new array of greater
length*/
for ( int i = 0; i < distanceMatrix.length; i++){
System.out.println (i+"\n");
if (i != row && i != column){/*As long as the element of distance matrix being covered is not*/
newArray[i - 1] = distanceMatrix[i];/*Assigns elements of the distance matrix to the new Array. use -1 because obviously
the array size will decrease since the rows that are of the shortest distance will be amalgamated into 1. */
}
}
for (int i = 0; i < distanceMatrix.length; ++i){
newArray[row][column] = Math.min(distanceMatrix [row][i], distanceMatrix [column][i]);
/*Puts the minimum value into the new array at the beginning.*/
++newRow;
/*Only increment the row value because going to input the new values downwards. */
}
distanceMatrix = newArray;
return distanceMatrix;
}
}
Andrew Hocker
Greenhorn

Joined: Feb 05, 2004
Posts: 13


[ March 04, 2004: Message edited by: Andrew Hocker ]

I don't really know anything, google does though.
 
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