public GradientWorker(AbstractBatchOptimizer.TrainingWorker <T> mainWorker, int threadIdx, int numThreads, IList <T> queue, AbstractDifferentiableFunction <T> fn, ConcatVector weights)
{
// This is to help the dynamic re-balancing of work queues
this.mainWorker = mainWorker;
this.threadIdx = threadIdx;
this.numThreads = numThreads;
this.queue = queue;
this.fn = fn;
this.weights = weights;
localDerivative = weights.NewEmptyClone();
}