Coverage for /home/runner/work/tket/tket/pytket/pytket/passes/resizeregpass.py: 100%

1# Copyright Quantinuum 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); 

4# you may not use this file except in compliance with the License. 

5# You may obtain a copy of the License at 

6# 

7# http://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, 

11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

12# See the License for the specific language governing permissions and 

13# limitations under the License. 

14 

15from pytket.circuit import Bit, Circuit 

16from pytket.unit_id import _TEMP_BIT_NAME 

17 

18from .._tket.passes import BasePass, CustomPass 

19 

20MAX_C_REG_WIDTH = 32 

21 

22 

23def _is_scratch(bit: Bit) -> bool: 

24 reg_name = bit.reg_name 

25 return bool(reg_name == _TEMP_BIT_NAME) or reg_name.startswith(f"{_TEMP_BIT_NAME}_") 

26 

27 

28def scratch_reg_resize_pass(max_size: int = MAX_C_REG_WIDTH) -> BasePass: 

29 """Create a pass that breaks up the internal scratch bit registers into smaller 

30 registers. 

31 

32 :param max_size: desired maximum size of scratch bit registers 

33 :return: a pass to break up the scratch registers 

34 """ 

35 

36 def trans(circ: Circuit, max_size: int = max_size) -> Circuit: 

37 # Find all scratch bits 

38 scratch_bits = list(filter(_is_scratch, circ.bits)) 

39 # If the total number of scratch bits exceeds the max width, rename them 

40 if len(scratch_bits) > max_size: 

41 bits_map = {} 

42 for i, bit in enumerate(scratch_bits): 

43 bits_map[bit] = Bit(f"{_TEMP_BIT_NAME}_{i//max_size}", i % max_size) 

44 circ.rename_units(bits_map) # type: ignore 

45 return circ 

46 

47 return CustomPass(trans, label="resize scratch bits")