You could try populating your SparseGrid2D with either an AtomicDouble or a
MutableDouble from commons-lang.
That way you can modify them without pulling them out of the grid and
putting them back in.
I am quite surprised it doesn't throw a ConcurrentModification exception
since you are effectively looping through a list of objects that you are
also modifying (with remove() and setLocation()). I suppose MASON passes a
safe copy in that bag.
On Mon, Jun 15, 2015 at 5:23 PM Sadat Chowdhury <[log in to unmask]> wrote:
> Hi All,
>
> When I increased the 2D world size of my system, there was a significant
> slowdown of the simulation. After I investigated using a profiler, it
> turned out to be due to methods that scan through 2D grids that in my
> system are defined as DoubleGrid2D.
>
> I have started converting those DoubleGrid2D into SparseGrid2D — because
> it fits the description perfectly: the world can be potentially unbounded
> and most times there will be fewer actual objects in the world.
>
> While it was relatively easy to convert all the parts that was setting and
> accessing objects in the grid — I am at a point where I have a lot of
> DoubleGrid2D’s that used full-scanning functions like .lowerBound() and
> .multiply(). Supposing I have a SparseGrid2D that has only one Double
> object per coordinate, what would be the most efficient (fast) way to
> implement a function similar to multiply() ?
>
> This is what I have so far, but I am just wondering if it can be done more
> efficiently (faster)?
>
> final public void SparseGrid2DMultiply(SparseGrid2D theGrid,
> double multiplier) {
> /*
> * theGrid is assumed to contain one and only one Double
> in a given
> * coordinate
> */
> Bag objects = theGrid.getAllObjects();
> for (Object object : objects) {
> double val = (Double) object;
> if (val != 0.0) {
> val = val * multiplier;
> Int2D location =
> theGrid.getObjectLocation(object);
> theGrid.remove(object);
> theGrid.setObjectLocation(val, location);
> }
> }
>
> }
>
> Any thoughts/comments is greatly appreciated,
> Sadat.
>
