From 7f41edd5280ea14e0b00fe684e7ac94894453955 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Tue, 26 Sep 2023 21:21:10 -0600
Subject: [PATCH 01/11] First pass of sharding data types

---
 Makefile                         |  4 ++
 pytket/phir/main.py              | 33 ++++++++++++---
 pytket/phir/sharding/__init__.py |  0
 pytket/phir/sharding/shard.py    | 51 +++++++++++++++++++++++
 pytket/phir/sharding/sharder.py  | 70 ++++++++++++++++++++++++++++++++
 requirements.txt                 |  1 +
 tests/data/qasm/baby.qasm        | 11 +++++
 tests/data/qasm/bv_n10.qasm      | 47 +++++++++++++++++++++
 tests/data/qasm/cond_1.qasm      | 16 ++++++++
 tests/data/qasm/simple.qasm      | 11 +++++
 tests/sample_data.py             | 24 +++++++++++
 tests/test_requirements.txt      |  1 +
 tests/test_sharder.py            | 25 ++++++++++++
 13 files changed, 288 insertions(+), 6 deletions(-)
 create mode 100644 Makefile
 create mode 100644 pytket/phir/sharding/__init__.py
 create mode 100644 pytket/phir/sharding/shard.py
 create mode 100644 pytket/phir/sharding/sharder.py
 create mode 100644 tests/data/qasm/baby.qasm
 create mode 100644 tests/data/qasm/bv_n10.qasm
 create mode 100644 tests/data/qasm/cond_1.qasm
 create mode 100644 tests/data/qasm/simple.qasm
 create mode 100644 tests/sample_data.py
 create mode 100644 tests/test_requirements.txt
 create mode 100644 tests/test_sharder.py

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..14274d8
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,4 @@
+.PHONY: tests
+
+tests:
+	pytest -s -x -vv tests/test*.py
\ No newline at end of file
diff --git a/pytket/phir/main.py b/pytket/phir/main.py
index bca21dd..542798b 100644
--- a/pytket/phir/main.py
+++ b/pytket/phir/main.py
@@ -1,10 +1,31 @@
-"""This is the main module of the pytket-phir package."""
+##############################################################################
+#
+# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
+# This software and all information and expression are the property of
+# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
+# contain trade secrets and may not, in whole or in part, be licensed,
+# used, duplicated, disclosed, or reproduced for any purpose without prior
+# written permission of Quantinuum LLC.
+#
+##############################################################################
 
+"""
+NOTE: Just a placeholder to allow convenient testing of the flows
+"""
 
-def hello_world() -> str:
-    """Print 'Hello, world!' to the console."""
-    hw = "Hello, World!"
-    return hw
+from pytket.qasm import circuit_from_qasm
+from pytket import Circuit
 
+from sharding.sharder import Sharder
 
-print(hello_world())  # noqa: T201
+# Load a qasm circuit and parse
+circuit: Circuit = circuit_from_qasm("tests/data/qasm/simple.qasm")
+
+# https://cqcl.github.io/tket/pytket/api/circuit_class.html
+
+# Just a little debuggin fun
+print('Input circuit:')
+print(circuit)
+print()
+
+sharding_output = Sharder(circuit).shard()
\ No newline at end of file
diff --git a/pytket/phir/sharding/__init__.py b/pytket/phir/sharding/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/pytket/phir/sharding/shard.py b/pytket/phir/sharding/shard.py
new file mode 100644
index 0000000..963f999
--- /dev/null
+++ b/pytket/phir/sharding/shard.py
@@ -0,0 +1,51 @@
+##############################################################################
+#
+# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
+# This software and all information and expression are the property of
+# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
+# contain trade secrets and may not, in whole or in part, be licensed,
+# used, duplicated, disclosed, or reproduced for any purpose without prior
+# written permission of Quantinuum LLC.
+#
+##############################################################################
+
+from __future__ import annotations
+from dataclasses import dataclass
+
+from pytket.circuit import Command
+from pytket.unit_id import UnitID
+
+@dataclass
+class Shard:
+    """
+    A shard is a logical grouping of operations that represents the unit by which
+    we actually do placement of qubits 
+    """
+
+    # The schedulable command of the shard
+    primary_command: Command
+
+    # The other commands related to the primary schedulable command, stored
+    # as a map of bit-handle (unitID) -> list[Command]
+    sub_commands: dict[UnitID, list[Command]]
+                    
+    # A set of the other shards this particular shard depends upon, and thus
+    # must be scheduled after 
+    depends_upon: set[Shard]
+
+    # def __init__(self, 
+    #              primary_command: Command,
+    #              sub_commands: dict[UnitID, list[Command]],
+    #              depends_upon: set[Shard]) -> None:
+        
+    #     # The schedulable command of the shard
+    #     self.primary_command = primary_command
+        
+    #     # The other commands related to the primary schedulable command, stored
+    #     # as a map of bit handle (unitID) -> list[Command]
+    #     self.sub_commands = sub_commands
+        
+    #     # A set of the other shards this particular shard depends upon, and thus
+    #     # must be scheduled after
+    #     self.depends_upon = depends_upon
+    
diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
new file mode 100644
index 0000000..d193d48
--- /dev/null
+++ b/pytket/phir/sharding/sharder.py
@@ -0,0 +1,70 @@
+##############################################################################
+#
+# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
+# This software and all information and expression are the property of
+# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
+# contain trade secrets and may not, in whole or in part, be licensed,
+# used, duplicated, disclosed, or reproduced for any purpose without prior
+# written permission of Quantinuum LLC.
+#
+##############################################################################
+
+from pytket import Circuit
+from pytket.circuit import Command, Op, OpType
+from pytket._tket.unit_id import UnitID
+
+from .shard import Shard
+
+NOT_IMPLEMENTED_OP_TYPES = [OpType.CircBox, OpType.WASM]
+
+class Sharder:
+    """
+    The sharder class is responsible for taking in a circuit in TKET representation
+    and converting it into shards that can be subsequently handled in the 
+    compilation pipeline.
+    """
+
+    def __init__(self, circuit: Circuit) -> None:
+        self._circuit = circuit
+        print(f'Sharder created for circuit {self._circuit}')
+        self._pending_commands: dict[UnitID, list[Command]] = {}
+        self._shards: list[Shard] = []
+
+    def shard(self) -> list[Shard]:
+        print('Sharding begins....')
+        # https://cqcl.github.io/tket/pytket/api/circuit.html#pytket.circuit.Command
+        
+        for command in self._circuit.get_commands():
+            self._process_command(command)
+        return self._shards
+    
+    def _process_command(self, command: Command) -> None:
+        print('Processing command: ', command.op, command.op.type, command.args)
+        if command.op.type in NOT_IMPLEMENTED_OP_TYPES:
+            raise NotImplementedError(f'OpType {command.op.type} not supported!')
+        
+        if self._is_op_schedulable(command.op):
+            print(f'Scheduling command: {command}')
+            self._build_shard(command)
+        else:
+            self._add_pending_command(command)
+
+
+    def _build_shard(self, command: Command) -> None:
+        shard = Shard(command, 
+                      {}, 
+                      [])
+        # TODO: Add sub operations
+        self._shards.append(shard)
+        print('Appended shard: ', shard)
+
+    def _add_pending_command(self, command: Command) -> None:
+        #if command.
+        pass
+
+    def _is_op_schedulable(self, op: Op) -> bool:
+        return (
+            op.type == OpType.Measure
+            or op.type == OpType.Reset
+            or (op.is_gate() and op.n_qubits > 1)
+            )
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
index 214e0e8..76bf51a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,3 +7,4 @@ pytest==7.4.2
 ruff==0.0.291
 sphinx==7.2.6
 wheel==0.41.2
+pytket==1.20.1
\ No newline at end of file
diff --git a/tests/data/qasm/baby.qasm b/tests/data/qasm/baby.qasm
new file mode 100644
index 0000000..65ec93f
--- /dev/null
+++ b/tests/data/qasm/baby.qasm
@@ -0,0 +1,11 @@
+OPENQASM 2.0;
+include "hqslib1.inc";
+
+qreg q[2];
+creg c[2];
+
+h q[0];
+h q[1];
+CX q[0], q[1];
+
+measure q->c;
\ No newline at end of file
diff --git a/tests/data/qasm/bv_n10.qasm b/tests/data/qasm/bv_n10.qasm
new file mode 100644
index 0000000..63775cc
--- /dev/null
+++ b/tests/data/qasm/bv_n10.qasm
@@ -0,0 +1,47 @@
+//@author Raymond Harry Rudy rudyhar@jp.ibm.com
+//Bernstein-Vazirani with 10 qubits.
+//Hidden string is 111111111
+OPENQASM 2.0;
+include "qelib1.inc";
+qreg qr[10];
+creg cr[9];
+h qr[0];
+h qr[1];
+h qr[2];
+h qr[3];
+h qr[4];
+h qr[5];
+h qr[6];
+h qr[7];
+h qr[8];
+x qr[9];
+h qr[9];
+barrier qr[0],qr[1],qr[2],qr[3],qr[4],qr[5],qr[6],qr[7],qr[8],qr[9];
+cx qr[0],qr[9];
+cx qr[1],qr[9];
+cx qr[2],qr[9];
+cx qr[3],qr[9];
+cx qr[4],qr[9];
+cx qr[5],qr[9];
+cx qr[6],qr[9];
+cx qr[7],qr[9];
+cx qr[8],qr[9];
+barrier qr[0],qr[1],qr[2],qr[3],qr[4],qr[5],qr[6],qr[7],qr[8],qr[9];
+h qr[0];
+h qr[1];
+h qr[2];
+h qr[3];
+h qr[4];
+h qr[5];
+h qr[6];
+h qr[7];
+h qr[8];
+measure qr[0] -> cr[0];
+measure qr[1] -> cr[1];
+measure qr[2] -> cr[2];
+measure qr[3] -> cr[3];
+measure qr[4] -> cr[4];
+measure qr[5] -> cr[5];
+measure qr[6] -> cr[6];
+measure qr[7] -> cr[7];
+measure qr[8] -> cr[8];
diff --git a/tests/data/qasm/cond_1.qasm b/tests/data/qasm/cond_1.qasm
new file mode 100644
index 0000000..6dfe4a5
--- /dev/null
+++ b/tests/data/qasm/cond_1.qasm
@@ -0,0 +1,16 @@
+OPENQASM 2.0;
+include "hqslib1.inc";
+
+qreg q[1];
+creg c[2];
+
+h q;
+measure q[0]->c[0];
+reset q;
+if (c==1) h q;
+if (c<1) h q;
+if (c>1) h q;
+if (c<=1) h q;
+if (c>=1) h q;
+if (c!=1) h q;
+measure q[0]->c[0];
diff --git a/tests/data/qasm/simple.qasm b/tests/data/qasm/simple.qasm
new file mode 100644
index 0000000..9ff7b72
--- /dev/null
+++ b/tests/data/qasm/simple.qasm
@@ -0,0 +1,11 @@
+OPENQASM 2.0;
+include "qelib1.inc";
+qreg q[1];
+creg c[1];
+
+h q[0];
+h q[0];
+h q[0];
+h q[0];
+h q[0];
+measure q->c;
diff --git a/tests/sample_data.py b/tests/sample_data.py
new file mode 100644
index 0000000..8951121
--- /dev/null
+++ b/tests/sample_data.py
@@ -0,0 +1,24 @@
+##############################################################################
+#
+# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
+# This software and all information and expression are the property of
+# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
+# contain trade secrets and may not, in whole or in part, be licensed,
+# used, duplicated, disclosed, or reproduced for any purpose without prior
+# written permission of Quantinuum LLC.
+#
+##############################################################################
+
+from enum import Enum
+
+from pytket import Circuit
+from pytket.qasm import circuit_from_qasm
+
+class QasmFiles(Enum):
+    simple = 1
+    cond_1 = 2
+    bv_n10 = 3
+    baby = 4
+
+def get_qasm_as_circuit(qasm_file: QasmFiles) -> Circuit:
+    return circuit_from_qasm(f'tests/data/qasm/{qasm_file.name}.qasm')
\ No newline at end of file
diff --git a/tests/test_requirements.txt b/tests/test_requirements.txt
new file mode 100644
index 0000000..de1887b
--- /dev/null
+++ b/tests/test_requirements.txt
@@ -0,0 +1 @@
+pytest==7.4.2
\ No newline at end of file
diff --git a/tests/test_sharder.py b/tests/test_sharder.py
new file mode 100644
index 0000000..edda096
--- /dev/null
+++ b/tests/test_sharder.py
@@ -0,0 +1,25 @@
+##############################################################################
+#
+# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
+# This software and all information and expression are the property of
+# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
+# contain trade secrets and may not, in whole or in part, be licensed,
+# used, duplicated, disclosed, or reproduced for any purpose without prior
+# written permission of Quantinuum LLC.
+#
+##############################################################################
+
+from .sample_data import get_qasm_as_circuit, QasmFiles
+from pytket.phir import Sharder 
+
+class TestSharder:
+
+    def test_ctor(self) -> None:
+        sharder = Sharder(get_qasm_as_circuit(QasmFiles.baby))
+        assert sharder is not None
+
+        output = sharder.shard()
+
+        assert len(output) > 0
+
+        print(output)
\ No newline at end of file

From ea8db4f324c8533ef85a3d8a23b1a24ced2b1488 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 09:53:56 -0600
Subject: [PATCH 02/11] first pass

---
 pytket/phir/main.py             |  8 +++++++-
 pytket/phir/sharding/sharder.py | 30 ++++++++++++++++++++++++------
 2 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/pytket/phir/main.py b/pytket/phir/main.py
index 542798b..3112fd1 100644
--- a/pytket/phir/main.py
+++ b/pytket/phir/main.py
@@ -19,7 +19,13 @@
 from sharding.sharder import Sharder
 
 # Load a qasm circuit and parse
-circuit: Circuit = circuit_from_qasm("tests/data/qasm/simple.qasm")
+#    ,=""=,
+#   c , _,{
+#   /\  @ )                 __
+#  /  ^~~^\          <=.,__/ '}=
+# (_/ ,, ,,)          \_ _>_/~
+#  ~\_(/-\)'-,_,_,_,-'(_)-(_) 
+circuit: Circuit = circuit_from_qasm("tests/data/qasm/baby.qasm")
 
 # https://cqcl.github.io/tket/pytket/api/circuit_class.html
 
diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
index d193d48..a742417 100644
--- a/pytket/phir/sharding/sharder.py
+++ b/pytket/phir/sharding/sharder.py
@@ -31,14 +31,21 @@ def __init__(self, circuit: Circuit) -> None:
         self._shards: list[Shard] = []
 
     def shard(self) -> list[Shard]:
+        """
+        Performs the sharding algorithm on the circuit the Sharder was initialized
+        with, returning the list of Shards needed to schedule
+        """
         print('Sharding begins....')
         # https://cqcl.github.io/tket/pytket/api/circuit.html#pytket.circuit.Command
-        
         for command in self._circuit.get_commands():
             self._process_command(command)
         return self._shards
     
     def _process_command(self, command: Command) -> None:
+        """
+        Handles a given TKET command (operation, bits, etc) according to the type
+        and the extant context within the Sharder
+        """
         print('Processing command: ', command.op, command.op.type, command.args)
         if command.op.type in NOT_IMPLEMENTED_OP_TYPES:
             raise NotImplementedError(f'OpType {command.op.type} not supported!')
@@ -51,16 +58,27 @@ def _process_command(self, command: Command) -> None:
 
 
     def _build_shard(self, command: Command) -> None:
+        """
+        Creates a Shard object given the extant sharding context and the schedulable
+        Command object passed in, and appends it to the Shard list
+        """
         shard = Shard(command, 
-                      {}, 
+                      self._pending_commands, 
                       [])
-        # TODO: Add sub operations
+        # TODO: Dependencies!
+        self._pending_commands = {}
         self._shards.append(shard)
-        print('Appended shard: ', shard)
+        print('Appended shard:', shard)
 
     def _add_pending_command(self, command: Command) -> None:
-        #if command.
-        pass
+        """
+        Adds a pending sub command to the buffer to be flushed when a schedulable
+        operation creates a Shard.
+        """
+        # TODO NJE: Need to make sure 'args[0]' is the right key to use.
+        if command.args[0] not in self._pending_commands:
+            self._pending_commands[command.args[0]] = []
+        self._pending_commands[command.args[0]].append(command)
 
     def _is_op_schedulable(self, op: Op) -> bool:
         return (

From 60f21be881475e848822d5cd966059981091d3d3 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 12:21:58 -0600
Subject: [PATCH 03/11] cleanup

---
 .pre-commit-config.yaml         |  2 +-
 Makefile                        |  7 ++++--
 pytket/phir/main.py             | 17 ++++++++------
 pytket/phir/sharding/shard.py   | 17 +++++++-------
 pytket/phir/sharding/sharder.py | 41 ++++++++++++++++++---------------
 pytket/phir/utils.py            |  6 -----
 requirements.txt                |  2 +-
 ruff.toml                       |  7 +++++-
 tests/data/qasm/baby.qasm       |  2 +-
 tests/sample_data.py            |  8 ++++---
 tests/test_main.py              |  8 -------
 tests/test_requirements.txt     |  2 +-
 tests/test_sharder.py           | 11 ++++-----
 tests/test_utils.py             | 10 --------
 14 files changed, 67 insertions(+), 73 deletions(-)
 delete mode 100644 pytket/phir/utils.py
 delete mode 100644 tests/test_main.py
 delete mode 100644 tests/test_utils.py

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 99f7ad3..b343688 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -37,5 +37,5 @@ repos:
       additional_dependencies: [
         pytest,
         types-setuptools,
-        pytket,
+        pytket==1.20.1,
       ]
diff --git a/Makefile b/Makefile
index 14274d8..98b123e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,7 @@
-.PHONY: tests
+.PHONY: tests, lint
 
 tests:
-	pytest -s -x -vv tests/test*.py
\ No newline at end of file
+	pytest -s -x -vv tests/test*.py
+
+lint:
+	pre-commit run --all-files
diff --git a/pytket/phir/main.py b/pytket/phir/main.py
index 3112fd1..7e33568 100644
--- a/pytket/phir/main.py
+++ b/pytket/phir/main.py
@@ -13,10 +13,10 @@
 NOTE: Just a placeholder to allow convenient testing of the flows
 """
 
-from pytket.qasm import circuit_from_qasm
-from pytket import Circuit
+from pytket.circuit import Circuit
+from pytket.qasm.qasm import circuit_from_qasm
 
-from sharding.sharder import Sharder
+from .sharding.sharder import Sharder
 
 # Load a qasm circuit and parse
 #    ,=""=,
@@ -24,14 +24,17 @@
 #   /\  @ )                 __
 #  /  ^~~^\          <=.,__/ '}=
 # (_/ ,, ,,)          \_ _>_/~
-#  ~\_(/-\)'-,_,_,_,-'(_)-(_) 
+#  ~\_(/-\)'-,_,_,_,-'(_)-(_)
 circuit: Circuit = circuit_from_qasm("tests/data/qasm/baby.qasm")
 
 # https://cqcl.github.io/tket/pytket/api/circuit_class.html
 
-# Just a little debuggin fun
-print('Input circuit:')
+# Just a little debugging fun
+print("Input circuit:")
 print(circuit)
 print()
 
-sharding_output = Sharder(circuit).shard()
\ No newline at end of file
+sharding_output = Sharder(circuit).shard()
+
+print("Sharding output:")
+print(sharding_output)
diff --git a/pytket/phir/sharding/shard.py b/pytket/phir/sharding/shard.py
index 963f999..5fb6564 100644
--- a/pytket/phir/sharding/shard.py
+++ b/pytket/phir/sharding/shard.py
@@ -10,16 +10,18 @@
 ##############################################################################
 
 from __future__ import annotations
+
 from dataclasses import dataclass
 
 from pytket.circuit import Command
 from pytket.unit_id import UnitID
 
+
 @dataclass
 class Shard:
     """
     A shard is a logical grouping of operations that represents the unit by which
-    we actually do placement of qubits 
+    we actually do placement of qubits
     """
 
     # The schedulable command of the shard
@@ -28,24 +30,23 @@ class Shard:
     # The other commands related to the primary schedulable command, stored
     # as a map of bit-handle (unitID) -> list[Command]
     sub_commands: dict[UnitID, list[Command]]
-                    
+
     # A set of the other shards this particular shard depends upon, and thus
-    # must be scheduled after 
+    # must be scheduled after
     depends_upon: set[Shard]
 
-    # def __init__(self, 
+    # def __init__(self,
     #              primary_command: Command,
     #              sub_commands: dict[UnitID, list[Command]],
     #              depends_upon: set[Shard]) -> None:
-        
+
     #     # The schedulable command of the shard
     #     self.primary_command = primary_command
-        
+
     #     # The other commands related to the primary schedulable command, stored
     #     # as a map of bit handle (unitID) -> list[Command]
     #     self.sub_commands = sub_commands
-        
+
     #     # A set of the other shards this particular shard depends upon, and thus
     #     # must be scheduled after
     #     self.depends_upon = depends_upon
-    
diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
index a742417..ddc4abf 100644
--- a/pytket/phir/sharding/sharder.py
+++ b/pytket/phir/sharding/sharder.py
@@ -9,24 +9,24 @@
 #
 ##############################################################################
 
-from pytket import Circuit
-from pytket.circuit import Command, Op, OpType
 from pytket._tket.unit_id import UnitID
+from pytket.circuit import Circuit, Command, Op, OpType
 
 from .shard import Shard
 
 NOT_IMPLEMENTED_OP_TYPES = [OpType.CircBox, OpType.WASM]
 
+
 class Sharder:
     """
     The sharder class is responsible for taking in a circuit in TKET representation
-    and converting it into shards that can be subsequently handled in the 
+    and converting it into shards that can be subsequently handled in the
     compilation pipeline.
     """
 
     def __init__(self, circuit: Circuit) -> None:
         self._circuit = circuit
-        print(f'Sharder created for circuit {self._circuit}')
+        print(f"Sharder created for circuit {self._circuit}")
         self._pending_commands: dict[UnitID, list[Command]] = {}
         self._shards: list[Shard] = []
 
@@ -35,54 +35,59 @@ def shard(self) -> list[Shard]:
         Performs the sharding algorithm on the circuit the Sharder was initialized
         with, returning the list of Shards needed to schedule
         """
-        print('Sharding begins....')
+        print("Sharding begins....")
         # https://cqcl.github.io/tket/pytket/api/circuit.html#pytket.circuit.Command
         for command in self._circuit.get_commands():
             self._process_command(command)
         return self._shards
-    
+
     def _process_command(self, command: Command) -> None:
         """
         Handles a given TKET command (operation, bits, etc) according to the type
         and the extant context within the Sharder
         """
-        print('Processing command: ', command.op, command.op.type, command.args)
+        print("Processing command: ", command.op, command.op.type, command.args)
         if command.op.type in NOT_IMPLEMENTED_OP_TYPES:
-            raise NotImplementedError(f'OpType {command.op.type} not supported!')
-        
+            msg = f"OpType {command.op.type} not supported!"
+            raise NotImplementedError(msg)
+
         if self._is_op_schedulable(command.op):
-            print(f'Scheduling command: {command}')
+            print(f"Scheduling command: {command}")
             self._build_shard(command)
         else:
             self._add_pending_command(command)
 
-
     def _build_shard(self, command: Command) -> None:
         """
         Creates a Shard object given the extant sharding context and the schedulable
         Command object passed in, and appends it to the Shard list
         """
-        shard = Shard(command, 
-                      self._pending_commands, 
-                      [])
+        shard = Shard(command, self._pending_commands, set())
         # TODO: Dependencies!
         self._pending_commands = {}
         self._shards.append(shard)
-        print('Appended shard:', shard)
+        print("Appended shard:", shard)
 
     def _add_pending_command(self, command: Command) -> None:
         """
         Adds a pending sub command to the buffer to be flushed when a schedulable
         operation creates a Shard.
         """
-        # TODO NJE: Need to make sure 'args[0]' is the right key to use.
+        # TODO: Need to make sure 'args[0]' is the right key to use.
         if command.args[0] not in self._pending_commands:
             self._pending_commands[command.args[0]] = []
         self._pending_commands[command.args[0]].append(command)
 
-    def _is_op_schedulable(self, op: Op) -> bool:
+    @staticmethod
+    def _is_op_schedulable(op: Op) -> bool:
+        """
+        Returns `True` if the operation is one that should be scheduled, that is,
+        that will have a shard created for it. This includes non-gate operations
+        like measure/reset as well as 2-qubit gates.
+        """
+        # TODO: This is almost certainly inadequate right now
         return (
             op.type == OpType.Measure
             or op.type == OpType.Reset
             or (op.is_gate() and op.n_qubits > 1)
-            )
\ No newline at end of file
+        )
diff --git a/pytket/phir/utils.py b/pytket/phir/utils.py
deleted file mode 100644
index 4114ecb..0000000
--- a/pytket/phir/utils.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""Utility functions for the pytket-phir package."""
-
-
-def add_numbers(a: int, b: int) -> int:
-    """Add two numbers and returns the result."""
-    return a + b
diff --git a/requirements.txt b/requirements.txt
index 76bf51a..c602e38 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,4 +7,4 @@ pytest==7.4.2
 ruff==0.0.291
 sphinx==7.2.6
 wheel==0.41.2
-pytket==1.20.1
\ No newline at end of file
+pytket==1.20.1
diff --git a/ruff.toml b/ruff.toml
index 7dc820d..8e3ca5f 100644
--- a/ruff.toml
+++ b/ruff.toml
@@ -42,7 +42,12 @@ select = [
   "YTT",  # flake8-2020
 ]
 
-ignore = []
+ignore = [
+  "T201", # no prints flake-8
+  "FIX002", # Allow todos
+  "TD002", # Allow no author todos
+  "TD003", # allow todos with no issues
+]
 
 [per-file-ignores]
 "__init__.py" = ["F401"]  # module imported but unused
diff --git a/tests/data/qasm/baby.qasm b/tests/data/qasm/baby.qasm
index 65ec93f..72a521b 100644
--- a/tests/data/qasm/baby.qasm
+++ b/tests/data/qasm/baby.qasm
@@ -8,4 +8,4 @@ h q[0];
 h q[1];
 CX q[0], q[1];
 
-measure q->c;
\ No newline at end of file
+measure q->c;
diff --git a/tests/sample_data.py b/tests/sample_data.py
index 8951121..e64afb2 100644
--- a/tests/sample_data.py
+++ b/tests/sample_data.py
@@ -11,8 +11,9 @@
 
 from enum import Enum
 
-from pytket import Circuit
-from pytket.qasm import circuit_from_qasm
+from pytket.circuit import Circuit
+from pytket.qasm.qasm import circuit_from_qasm
+
 
 class QasmFiles(Enum):
     simple = 1
@@ -20,5 +21,6 @@ class QasmFiles(Enum):
     bv_n10 = 3
     baby = 4
 
+
 def get_qasm_as_circuit(qasm_file: QasmFiles) -> Circuit:
-    return circuit_from_qasm(f'tests/data/qasm/{qasm_file.name}.qasm')
\ No newline at end of file
+    return circuit_from_qasm(f"tests/data/qasm/{qasm_file.name}.qasm")
diff --git a/tests/test_main.py b/tests/test_main.py
deleted file mode 100644
index 9d673cb..0000000
--- a/tests/test_main.py
+++ /dev/null
@@ -1,8 +0,0 @@
-"""Tests for pytket-phir.main module."""
-
-from pytket.phir.main import hello_world
-
-
-def test_hello_world():
-    """Test the hello_world function."""
-    assert hello_world() == "Hello, World!"
diff --git a/tests/test_requirements.txt b/tests/test_requirements.txt
index de1887b..2a929ed 100644
--- a/tests/test_requirements.txt
+++ b/tests/test_requirements.txt
@@ -1 +1 @@
-pytest==7.4.2
\ No newline at end of file
+pytest==7.4.2
diff --git a/tests/test_sharder.py b/tests/test_sharder.py
index edda096..ee8815a 100644
--- a/tests/test_sharder.py
+++ b/tests/test_sharder.py
@@ -9,17 +9,16 @@
 #
 ##############################################################################
 
-from .sample_data import get_qasm_as_circuit, QasmFiles
-from pytket.phir import Sharder 
+from pytket.phir.sharding.sharder import Sharder
+
+from .sample_data import QasmFiles, get_qasm_as_circuit
 
-class TestSharder:
 
+class TestSharder:
     def test_ctor(self) -> None:
         sharder = Sharder(get_qasm_as_circuit(QasmFiles.baby))
         assert sharder is not None
 
         output = sharder.shard()
 
-        assert len(output) > 0
-
-        print(output)
\ No newline at end of file
+        assert len(output) == 2  # noqa: PLR2004
diff --git a/tests/test_utils.py b/tests/test_utils.py
deleted file mode 100644
index d181a80..0000000
--- a/tests/test_utils.py
+++ /dev/null
@@ -1,10 +0,0 @@
-"""Tests for pytket-phir.utils."""
-
-from pytket.phir.utils import add_numbers
-
-
-def test_add():
-    """Test the add function."""
-    assert add_numbers(2, 3) == 5  # noqa: PLR2004
-    assert add_numbers(0, 0) == 0
-    assert add_numbers(-1, 1) == 0

From c5bdcb00ef36e95e6d3c4674d95e4ad2fa25e72f Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 12:31:58 -0600
Subject: [PATCH 04/11] trying a fix

---
 pytket/phir/sharding/sharder.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
index ddc4abf..482df68 100644
--- a/pytket/phir/sharding/sharder.py
+++ b/pytket/phir/sharding/sharder.py
@@ -9,8 +9,8 @@
 #
 ##############################################################################
 
-from pytket._tket.unit_id import UnitID
 from pytket.circuit import Circuit, Command, Op, OpType
+from pytket.unit_id import UnitID
 
 from .shard import Shard
 

From b13d489d0604765d40a8284cc20ccaf21b9cfefb Mon Sep 17 00:00:00 2001
From: Kartik Singhal <kartik.singhal@quantinuum.com>
Date: Wed, 27 Sep 2023 15:00:03 -0500
Subject: [PATCH 05/11] Fix namespace collision introduced by unneeded
 __init__.py

---
 .pre-commit-config.yaml | 4 ++--
 pyproject.toml          | 1 +
 pytket/__init__.py      | 0
 3 files changed, 3 insertions(+), 2 deletions(-)
 delete mode 100644 pytket/__init__.py

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b343688..4210b23 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -33,9 +33,9 @@ repos:
     hooks:
     - id: mypy
       pass_filenames: false
-      args: [.]
+      args: [--package=pytket.phir, --package=tests]
       additional_dependencies: [
         pytest,
-        types-setuptools,
         pytket==1.20.1,
+        types-setuptools,
       ]
diff --git a/pyproject.toml b/pyproject.toml
index aafb143..c60e2c1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,3 +16,4 @@ where = ["."]
 pythonpath = [
   "."
 ]
+filterwarnings = ["ignore:::lark.s*"]
diff --git a/pytket/__init__.py b/pytket/__init__.py
deleted file mode 100644
index e69de29..0000000

From 3f529768a46f7c1b550b66c813757a61eded1aeb Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 14:33:12 -0600
Subject: [PATCH 06/11] small changes

---
 pytket/phir/sharding/sharder.py | 4 ++--
 tests/test_sharder.py           | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
index 482df68..7f5ab54 100644
--- a/pytket/phir/sharding/sharder.py
+++ b/pytket/phir/sharding/sharder.py
@@ -51,7 +51,7 @@ def _process_command(self, command: Command) -> None:
             msg = f"OpType {command.op.type} not supported!"
             raise NotImplementedError(msg)
 
-        if self._is_op_schedulable(command.op):
+        if self.is_op_schedulable(command.op):
             print(f"Scheduling command: {command}")
             self._build_shard(command)
         else:
@@ -79,7 +79,7 @@ def _add_pending_command(self, command: Command) -> None:
         self._pending_commands[command.args[0]].append(command)
 
     @staticmethod
-    def _is_op_schedulable(op: Op) -> bool:
+    def is_op_schedulable(op: Op) -> bool:
         """
         Returns `True` if the operation is one that should be scheduled, that is,
         that will have a shard created for it. This includes non-gate operations
diff --git a/tests/test_sharder.py b/tests/test_sharder.py
index ee8815a..dbfe57b 100644
--- a/tests/test_sharder.py
+++ b/tests/test_sharder.py
@@ -21,4 +21,4 @@ def test_ctor(self) -> None:
 
         output = sharder.shard()
 
-        assert len(output) == 2  # noqa: PLR2004
+        assert len(output) == 3  # noqa: PLR2004

From a7c1c68737d8259adfca260af2270332a9c0b3f0 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 14:42:50 -0600
Subject: [PATCH 07/11] removing

---
 tests/test_requirements.txt | 1 -
 1 file changed, 1 deletion(-)
 delete mode 100644 tests/test_requirements.txt

diff --git a/tests/test_requirements.txt b/tests/test_requirements.txt
deleted file mode 100644
index 2a929ed..0000000
--- a/tests/test_requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-pytest==7.4.2

From f759167d9f10a04a2b1e2b1429c67e0a918b0798 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 15:20:40 -0600
Subject: [PATCH 08/11] feedback 1

---
 pytket/phir/sharding/shard.py | 20 +-------------------
 ruff.toml                     |  5 ++++-
 tests/test_sharder.py         |  2 +-
 3 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/pytket/phir/sharding/shard.py b/pytket/phir/sharding/shard.py
index 5fb6564..7ae8beb 100644
--- a/pytket/phir/sharding/shard.py
+++ b/pytket/phir/sharding/shard.py
@@ -9,8 +9,6 @@
 #
 ##############################################################################
 
-from __future__ import annotations
-
 from dataclasses import dataclass
 
 from pytket.circuit import Command
@@ -33,20 +31,4 @@ class Shard:
 
     # A set of the other shards this particular shard depends upon, and thus
     # must be scheduled after
-    depends_upon: set[Shard]
-
-    # def __init__(self,
-    #              primary_command: Command,
-    #              sub_commands: dict[UnitID, list[Command]],
-    #              depends_upon: set[Shard]) -> None:
-
-    #     # The schedulable command of the shard
-    #     self.primary_command = primary_command
-
-    #     # The other commands related to the primary schedulable command, stored
-    #     # as a map of bit handle (unitID) -> list[Command]
-    #     self.sub_commands = sub_commands
-
-    #     # A set of the other shards this particular shard depends upon, and thus
-    #     # must be scheduled after
-    #     self.depends_upon = depends_upon
+    depends_upon: set["Shard"]
diff --git a/ruff.toml b/ruff.toml
index 8e3ca5f..c66ae97 100644
--- a/ruff.toml
+++ b/ruff.toml
@@ -51,7 +51,10 @@ ignore = [
 
 [per-file-ignores]
 "__init__.py" = ["F401"]  # module imported but unused
-"tests/*"     = ["S101"]  # Use of `assert` detected
+"tests/*"     = [
+    "S101", # Use of `assert` detected
+    "PLR2004" # Magic constants
+  ]
 
 [pydocstyle]
 convention = "google"
diff --git a/tests/test_sharder.py b/tests/test_sharder.py
index dbfe57b..1249284 100644
--- a/tests/test_sharder.py
+++ b/tests/test_sharder.py
@@ -21,4 +21,4 @@ def test_ctor(self) -> None:
 
         output = sharder.shard()
 
-        assert len(output) == 3  # noqa: PLR2004
+        assert len(output) == 3

From 34f045c9e8422e0ec72d4933e1640a976a722301 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Wed, 27 Sep 2023 17:14:39 -0600
Subject: [PATCH 09/11] rename of method in sharder

---
 pytket/phir/sharding/sharder.py | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
index 7f5ab54..4371093 100644
--- a/pytket/phir/sharding/sharder.py
+++ b/pytket/phir/sharding/sharder.py
@@ -51,8 +51,8 @@ def _process_command(self, command: Command) -> None:
             msg = f"OpType {command.op.type} not supported!"
             raise NotImplementedError(msg)
 
-        if self.is_op_schedulable(command.op):
-            print(f"Scheduling command: {command}")
+        if self.should_op_create_shard(command.op):
+            print(f"Building shard for command: {command}")
             self._build_shard(command)
         else:
             self._add_pending_command(command)
@@ -79,11 +79,10 @@ def _add_pending_command(self, command: Command) -> None:
         self._pending_commands[command.args[0]].append(command)
 
     @staticmethod
-    def is_op_schedulable(op: Op) -> bool:
+    def should_op_create_shard(op: Op) -> bool:
         """
-        Returns `True` if the operation is one that should be scheduled, that is,
-        that will have a shard created for it. This includes non-gate operations
-        like measure/reset as well as 2-qubit gates.
+        Returns `True` if the operation is one that should result in shard creation.
+        This includes non-gate operations like measure/reset as well as 2-qubit gates.
         """
         # TODO: This is almost certainly inadequate right now
         return (

From c2eb07831abbc9432d9d1da75e12205349bde3a7 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Thu, 28 Sep 2023 08:29:31 -0600
Subject: [PATCH 10/11] removing headers

---
 pytket/phir/main.py             | 11 -----------
 pytket/phir/sharding/shard.py   | 11 -----------
 pytket/phir/sharding/sharder.py | 11 -----------
 tests/sample_data.py            | 11 -----------
 tests/test_sharder.py           |  8 --------
 5 files changed, 52 deletions(-)

diff --git a/pytket/phir/main.py b/pytket/phir/main.py
index 7e33568..a8d37c1 100644
--- a/pytket/phir/main.py
+++ b/pytket/phir/main.py
@@ -1,14 +1,3 @@
-##############################################################################
-#
-# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
-# This software and all information and expression are the property of
-# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
-# contain trade secrets and may not, in whole or in part, be licensed,
-# used, duplicated, disclosed, or reproduced for any purpose without prior
-# written permission of Quantinuum LLC.
-#
-##############################################################################
-
 """
 NOTE: Just a placeholder to allow convenient testing of the flows
 """
diff --git a/pytket/phir/sharding/shard.py b/pytket/phir/sharding/shard.py
index 7ae8beb..0ff4cb8 100644
--- a/pytket/phir/sharding/shard.py
+++ b/pytket/phir/sharding/shard.py
@@ -1,14 +1,3 @@
-##############################################################################
-#
-# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
-# This software and all information and expression are the property of
-# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
-# contain trade secrets and may not, in whole or in part, be licensed,
-# used, duplicated, disclosed, or reproduced for any purpose without prior
-# written permission of Quantinuum LLC.
-#
-##############################################################################
-
 from dataclasses import dataclass
 
 from pytket.circuit import Command
diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
index 4371093..b3e9cf1 100644
--- a/pytket/phir/sharding/sharder.py
+++ b/pytket/phir/sharding/sharder.py
@@ -1,14 +1,3 @@
-##############################################################################
-#
-# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
-# This software and all information and expression are the property of
-# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
-# contain trade secrets and may not, in whole or in part, be licensed,
-# used, duplicated, disclosed, or reproduced for any purpose without prior
-# written permission of Quantinuum LLC.
-#
-##############################################################################
-
 from pytket.circuit import Circuit, Command, Op, OpType
 from pytket.unit_id import UnitID
 
diff --git a/tests/sample_data.py b/tests/sample_data.py
index e64afb2..73487d1 100644
--- a/tests/sample_data.py
+++ b/tests/sample_data.py
@@ -1,14 +1,3 @@
-##############################################################################
-#
-# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
-# This software and all information and expression are the property of
-# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
-# contain trade secrets and may not, in whole or in part, be licensed,
-# used, duplicated, disclosed, or reproduced for any purpose without prior
-# written permission of Quantinuum LLC.
-#
-##############################################################################
-
 from enum import Enum
 
 from pytket.circuit import Circuit
diff --git a/tests/test_sharder.py b/tests/test_sharder.py
index 1249284..68e3c37 100644
--- a/tests/test_sharder.py
+++ b/tests/test_sharder.py
@@ -1,14 +1,6 @@
 ##############################################################################
 #
 # (c) 2023 @ Quantinuum LLC. All Rights Reserved.
-# This software and all information and expression are the property of
-# Quantinuum LLC, are Quantinuum LLC Confidential & Proprietary,
-# contain trade secrets and may not, in whole or in part, be licensed,
-# used, duplicated, disclosed, or reproduced for any purpose without prior
-# written permission of Quantinuum LLC.
-#
-##############################################################################
-
 from pytket.phir.sharding.sharder import Sharder
 
 from .sample_data import QasmFiles, get_qasm_as_circuit

From 1232f14ee59b0847af4d9cec29aad1e7dfad31e1 Mon Sep 17 00:00:00 2001
From: Neal Erickson <neal.erickson@quantinuum.com>
Date: Thu, 28 Sep 2023 10:10:46 -0600
Subject: [PATCH 11/11] mistake in deletion

---
 tests/test_sharder.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/tests/test_sharder.py b/tests/test_sharder.py
index 68e3c37..7a6c533 100644
--- a/tests/test_sharder.py
+++ b/tests/test_sharder.py
@@ -1,6 +1,3 @@
-##############################################################################
-#
-# (c) 2023 @ Quantinuum LLC. All Rights Reserved.
 from pytket.phir.sharding.sharder import Sharder
 
 from .sample_data import QasmFiles, get_qasm_as_circuit