# Source

A `Source` is the action of importing method declarations from other DML scripts. This function allows one to define a function in DML and use it in the python API.

Although it is possible to generate sources with the function calls or object construction specified below, the recommended way is to use the method defined on `SystemDSContext` called source to construct one using a path to the dml file to source.

class `systemds.operator.``Source`(sds_context: SystemDSContext, path: str, name: str, print_imported_methods: bool = False)
  `__init__`(sds_context: SystemDSContext, path: str, name: str, print_imported_methods: bool = False) → Import

    Create general OperationNode

    Parameters

      - sds_context – The SystemDS context for performing the operations

      - operation – The name of the DML function to execute

      - unnamed_input_nodes – inputs identified by their position, not name

      - named_input_nodes – inputs with their respective parameter name

      - output_type – type of the output in DML (double, matrix etc.)

      - is_python_local_data – if the data is local in python e.g. Numpy arrays

      - number_of_outputs – If set to other value than 1 then it is expected that this operation node returns multiple values. If set remember to set the output_types value as well.

      - output_types – The types of output in a multi output scenario. Default is None, and means every multi output is a matrix.

  `code_line`(var_name: str, unnamed_input_vars: Sequence[str], named_input_vars: Dict[str, str]) → str

    Generates the DML code line equal to the intended action of this node.

    Parameters

      - var_name – Name of DML-variable this nodes result should be saved in

      - unnamed_input_vars – all strings representing the unnamed parameters

      - named_input_vars – all strings representing the named parameters (name value pairs)

    Returns

      the DML code line that is equal to this operation

  `compute`(verbose: bool = False, lineage: bool = False)

    Get result of this operation. Builds the dml script and executes it in SystemDS, before this method is called all operations are only building the DAG without actually executing (lazy evaluation).

    Parameters

      - verbose – Can be activated to print additional information such as created DML-Script

      - lineage – Can be activated to print lineage trace till this node

    Returns

      the output as an python builtin data type or numpy array