private double dotProduct(Tensor tensor, List<Tensor> tensors, int iterations) {
        double result = 0;
        for (int i = 0; i < iterations; i++)
            result = dotProduct(tensor, tensors);
        return result;
    }
Microbenchmark of tensor operations.

@author bratseth
vespajlib/src/test/java/com/yahoo/tensor/TensorFunctionBenchmark.java