fun learn(examples: Array<DoubleArray>) {
        var example: RealMatrix
        var result: RealMatrix = Array2DRowRealMatrix(size, size)

        for (e in examples) {
            example = Array2DRowRealMatrix(e)
            result = result.add(example.multiply(example.transpose()))
        }
        println("Learning done")

        for ( (i,row) in result.data.withIndex()) {
            neurons[i].weights = row
        }
    }