qat.pbo.PatternGroup

class qat.pbo.PatternGroup

A PatternGroup is a set of equivalent patterns. You can create a pattern group:

• by calling the method new_group() of PatternManager

• by instantiating this class manually (without passing any argument to the constructor) and then by linking this group to a PatternManager (use of groups or collections arguments in the constructor of PatternManager)

For instance, the following code block links a PatternGroup to a PatternManager:

from qat.pbo import PatternManager
from qat.pbo.collections import INVOLUTIONS

# The INVOLUTIONS object is a list of PatternGroup
# This collection is used to remove patterns H-H, CNOT-CNOT, ...
print("The collection 'INVOLUTIONS' is", INVOLUTIONS)

# Defines a plugin removing H-H, CNOT-CNOT, ...
plugin = PatternManager(collections=[INVOLUTIONS])

The collection 'INVOLUTIONS' is [<libcpp_pbo.PatternGroup object at 0x7fbdcb9ecf70>]

add_pattern(pattern: list)

Add a pattern to this group

from qat.pbo import PatternGroup

# Define a group of equivalent patterns
group_swap = PatternGroup()

# Add items to this group
group_swap.add_pattern([("SWAP", {0, 1})])
group_swap.add_pattern([("CNOT", [0, 1]), ("CNOT", [1, 0]), ("CNOT", [0, 1])])

If the gate is undirected, use a set to describe qubits instead of a list: all the directed patterns will be iterated

Warning

Each undirected gate will increase the number of pattern by \(q!\) where \(q\) is the number of qubits of the gate

Parameters:

pattern (pattern like) – Please refer to Writing patterns

pattern_to_remove(pattern: list)

Define a pattern to this group which have to be removed

from qat.pbo import PatternGroup

# Define a group of equivalent patterns
group_swap = PatternGroup()

# Add items to this group
group_swap.pattern_to_remove([("SWAP", {0, 1})])  # Pattern that should disappear in the final circuit
group_swap.add_pattern([("CNOT", [0, 1]), ("CNOT", [1, 0]), ("CNOT", [0, 1])])

If the gate is undirected, use a set to describe qubits instead of a list: all the directed patterns will be iterated

Warning

Each undirected gate will increase the number of pattern by \(q!\) where \(q\) is the number of qubits of the gate

Parameters:

pattern (pattern like) – Please refer to Writing patterns