Pipeline

class lsst.pipe.base.Pipeline(iterable=None)

Bases: list

Pipeline is a sequence of TaskDef objects.

Pipeline is given as one of the inputs to a supervising framework which builds execution graph out of it. Pipeline contains a sequence of TaskDef instances.

Main purpose of this class is to provide a mechanism to pass pipeline definition from users to supervising framework. That mechanism is implemented using simple serialization and de-serialization via pickle. Note that pipeline serialization is not guaranteed to be compatible between different versions or releases.

In current implementation Pipeline is a list (it inherits from list) and one can use all list methods on pipeline. Content of the pipeline can be modified, it is up to the client to verify that modifications leave pipeline in a consistent state. One could modify container directly by adding or removing its elements.

Parameters:

pipeline : iterable of TaskDef instances, optional

Initial sequence of tasks.

Methods Summary

append(object)
clear()
copy()
count(value)
extend(iterable)
index(value, [start, [stop]])	Raises ValueError if the value is not present.
insert	L.insert(index, object) – insert object before index
labelIndex(label)	Return task index given its label.
pop([index])	Raises IndexError if list is empty or index is out of range.
remove(value)	Raises ValueError if the value is not present.
reverse	L.reverse() – reverse IN PLACE
sort([key, reverse])

Methods Documentation

append(object) → None -- append object to end

clear() → None -- remove all items from L

copy() → list -- a shallow copy of L

count(value) → integer -- return number of occurrences of value

extend(iterable) → None -- extend list by appending elements from the iterable

index(value[, start[, stop]]) → integer -- return first index of value.

Raises ValueError if the value is not present.

insert()

L.insert(index, object) – insert object before index

labelIndex(label)

Return task index given its label.

Parameters:

label : str

Task label.

Returns:

index : int

Task index, or -1 if label is not found.

pop([index]) → item -- remove and return item at index (default last).

Raises IndexError if list is empty or index is out of range.

remove(value) → None -- remove first occurrence of value.

Raises ValueError if the value is not present.

reverse()

L.reverse() – reverse IN PLACE

sort(key=None, reverse=False) → None -- stable sort *IN PLACE*