private Tensor unitVector(String dimension) {
        return Tensor.Builder.of(new TensorType.Builder().indexed(dimension, 1).build())
                .cell().label(dimension, 0).value(1).build();
    }
Microbenchmark of tensor operations.

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