inputs.add(dataInput);
// set up block reader for options input
BlockReader options = getInput(INPUT_OPTIONS);
TypedOptionalActivityInput optionsInput =
new TypedOptionalActivityInput(INPUT_OPTIONS, Object.class, DEFAULT_OPTIONS);
optionsInput.setBlockReader(options);
inputs.add(optionsInput);
// set up block reader for options input
BlockReader algorithm = getInput(INPUT_ALGORITHM_CLASS);
TypedOptionalActivityInput algorithmInput =
new TypedOptionalActivityInput(INPUT_ALGORITHM_CLASS, Object.class, DEFAULT_ALGORITHM);
algorithmInput.setBlockReader(algorithm);
inputs.add(algorithmInput);
// set up block reader for indexes of nominal values columns
BlockReader indexes = getInput(INPUT_COLUMN_INDICES);
if (indexes == null)