private List<Tensor> matrix(int vectorSize, TensorType.Dimension.Type dimensionType, int vectorCount) {
        TensorType.Builder typeBuilder = new TensorType.Builder();
        typeBuilder.dimension("i", dimensionType == Type.indexedBound ? Type.indexedUnbound : dimensionType);
        vectorType(typeBuilder, "x", dimensionType, vectorSize);
        Tensor.Builder builder = Tensor.Builder.of(typeBuilder.build());
        for (int i = 0; i < vectorCount; i++) {
            for (int j = 0; j < vectorSize; j++) {
                builder.cell()
                        .label("i", String.valueOf(i))
                        .label("x", String.valueOf(j))
                        .value((i+1)*(j+1));
            }
        }
        return List.of(builder.build());
    }
Create a matrix of vectors (in dimension i) where each vector has the dimension x.
This matrix contains the same vectors as returned by createVectors, in a single list element for convenience.
vespajlib/src/test/java/com/yahoo/tensor/TensorTestCase.java