private static TensorFieldValue createTensorFromCells(TokenBuffer buffer, Field field) {
        TensorDataType tensorDataType = (TensorDataType)field.getDataType();
        TensorType originalType = tensorDataType.getTensorType();
        TensorType convertedType = TensorModifyUpdate.convertDimensionsToMapped(originalType);

        Tensor.Builder tensorBuilder = Tensor.Builder.of(convertedType);
        readTensorCells(buffer, tensorBuilder);
        Tensor tensor = tensorBuilder.build();

        validateBounds(tensor, originalType);

        return new TensorFieldValue(tensor);
    }
Reader of a "modify" update of a tensor field.
document/src/main/java/com/yahoo/document/json/readers/TensorModifyUpdateReader.java