Utilities¶

Module name: blackbird.utils

This module contains utility functions for Blackbird programs, including generating directed acyclic graphs, and pattern matching and Blackbird programs and templates.

Summary¶

`TemplateError`	Exception class for template related errors
`to_DiGraph`(program)	Convert a Blackbird program to a directed acyclic graph.
`match_template`(template, program)	Match a template against a Blackbird program, returning template parameter values.

Code details¶

class Command(name, args, kwargs, modes)¶

namedtuple: encapsulate a specific quantum operation

args¶: Alias for field number 1

kwargs¶: Alias for field number 2

modes¶: Alias for field number 3

name¶: Alias for field number 0

exception TemplateError[source]¶: Exception class for template related errors

to_DiGraph(program)[source]¶

Convert a Blackbird program to a directed acyclic graph.

The resulting graph has nodes representing quantum operations, and edges representing dependent/successor operations.

Each node is labelled by an integer; note attributes are used to store information about the node:

'name' (str): name of the quantum operation (e.g., 'S2gate')
'args' (list): positional arguments of the operation
'kwargs' (dict): keyword arguments of the operation
'modes' (tuple[int]): modes the operation acts on

Parameters: program (blackbird.Program) – a Blackbird program
Returns: the directed acyclic graph representing the quantum program
Return type: networkx.DiGraph

match_template(template, program)[source]¶

Match a template against a Blackbird program, returning template parameter values.

For example, consider the following template and program:

template = blackbird.loads("""\
name prog
version 1.0

Dgate(-{r}, 0.45) | 1
Vac | 2
Sgate({r}, 2*{phi}-1) | 0
""")

program = blackbird.loads("""\
name prog
version 1.0

Sgate(0.543, -1.432*pi) | 0
Dgate(-0.543, 0.45) | 1
Vac | 2
""")

By applying the match_template function, we can match the template parameters:

>>> res = match_template(template, program)
>>> print(res)
{'r': 0.543, 'phi': -1.74938033997029}

Verifying this is correct:

>>> print((-1.432*np.pi+1)/2)
-1.7493803399702919

Note

The template and the Blackbird program to match must have the same version number and target, otherwise an TemplateError will be raised.

Parameters

template (blackbird.Program) – the Blackbird template
program (blackbird.Program) – a Blackbird program to match against the template

Returns

mapping from the template parameter name to a numerical value.

Return type

dict[str, Number]