Re: [Repast-developer] Comment about DoubleMatrix and copyTo method.

[Nick C. <nic...@ve...>]

Yes. I think this is good. Do you have CVS access? If so, go ahead and
commit this.

Nick

On Fri, 2003-05-23 at 12:08, Mark R. Diggory wrote:
> Is it really neccessary to reallocate memory everytime you use 
> DoubleArray.copyTo? This seems to be expensive to me, especially in the 
> case of Diffuse2D.
> 
> 
>   /**
>    * Copies the double[] in this DoubleMatrix to the specified DoubleMatrix.
>    */
>   public void copyMatrixTo(DoubleMatrix dm) {
>     double[] aMatrix = new double[sizeY * sizeX];
>     System.arraycopy(matrix, 0, aMatrix, 0, sizeY * sizeX);
>     dm.matrix = aMatrix;
>   }
> 
> I think the above method could easily be written as:
> 
>   public void copyMatrixTo(DoubleMatrix dm) {
>     System.arraycopy(matrix, 0, dm.matrix , 0, sizeY * sizeX);
>   }
> 
> without having to build a new double array. I understand that the matri 
> could be different sizes so:
> 
>   /**
>    * Copies the double[] in this DoubleMatrix to the specified DoubleMatrix.
>    */
>   public void copyMatrixTo(DoubleMatrix dm) {
>     if(matix.length != dm.matrix.length){
>        double[] aMatrix = new double[sizeY * sizeX];
>        System.arraycopy(matrix, 0, aMatrix, 0, sizeY * sizeX);
>        dm.matrix = aMatrix;
>    }else{
>       System.arraycopy(matrix, 0, dm.matrix , 0, sizeY * sizeX);
>   }
> }
> 
> captures that case while still providing efficient copying of 
> DoubleArrays of equal sizes by reusing allocated memory.
> 
> what do you think?
> Mark
> 
> 
> 
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Nick Collier <nic...@ve...>