From 72a47a269f65a2c6a365e30d0cea356d5889ae8d Mon Sep 17 00:00:00 2001
From: Kartik Singhal <kartik.singhal@quantinuum.com>
Date: Mon, 23 Oct 2023 11:28:30 -0500
Subject: [PATCH] feat(model): Angle unit is appended after the angles list
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Based on feedback from Ciarán on the PR
---
 phir/model.py     |  6 +-----
 phir_spec_qasm.md | 11 +++++------
 schema.json       | 33 +++++++++++++++------------------
 3 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/phir/model.py b/phir/model.py
index c5cecf1..6a6f6c2 100644
--- a/phir/model.py
+++ b/phir/model.py
@@ -68,17 +68,13 @@ class Op(BaseModel, abc.ABC):
     metadata: dict[str, Any] | None = None
 
 
-Radian: TypeAlias = float
-PiRadian = NewType("PiRadian", tuple[float, Literal["pi"]])
-
-
 class QOp(Op):
     """Quantum operation."""
 
     qop: str
     returns: list[Bit] | None = None
     args: list[Bit | list[Bit]]
-    angles: list[Radian | PiRadian] | None = None
+    angles: tuple[list[float], Literal["rad", "pi"]] | None = None
 
 
 class COp(Op):
diff --git a/phir_spec_qasm.md b/phir_spec_qasm.md
index 2af2540..7e64435 100644
--- a/phir_spec_qasm.md
+++ b/phir_spec_qasm.md
@@ -312,15 +312,14 @@ The generic qop gate structure is:
 ```json5
 {
   "qop": str,
-  "angles": [float | [float, "pi"] ...],  // Include if gate has one or more angles.
+  "angles": [[float...], "rad" | "pi"],  // Include if gate has one or more angles.
   "args": [qubit_id, ... | [qubit_id, ... ], ...],  // Can be a list of qubit IDs or a list of lists for multi-qubit gates.
   "metadata": {}, // Optional metadata for potential auxiliary info or to be utilized by error models.
   "returns": [[str, int], ...]  // Include if gate produces output, e.g., a measurement.
 }
 ```
 
-`"angles"` list is expected to be in radians, ie, `float`. For convenience, multiples of ᴨ (pi radians) are also supported in the
-form of tuples `[float, "pi"]`.
+`"angles"` is a tuple of a list of `float`s and a unit. The units supported are radians (preferred) and multiples of ᴨ (pi radians).
 
 Table II details the available qops.
 
@@ -353,12 +352,12 @@ However, multi-qubit gates, such as `CX`, use a list of lists of qubit IDs. E.g.
 
 PECOS ensures all qubit IDs in `"args"` are unique, meaning gates don't overlap on the same qubits.
 
-For gates with one or multiple angles, angles are denoted as floats (or pi radians, not shown) in the `"angles"` list:
+For gates with one or multiple angles, angles are denoted as floats and a unit in the `"angles"` list:
 
 ```json5
 {
   "qop": "RZZ",
-  "angles": [0.173],
+  "angles": [[0.173], "rad"],
   "args": [
     [ ["q", 0], ["q", 1] ],
     [ ["q", 2], ["q", 3] ]
@@ -370,7 +369,7 @@ For gates with one or multiple angles, angles are denoted as floats (or pi radia
 ```json5
 {
   "qop": "U1q",
-  "angles": [0.524, 1.834],
+  "angles": [[0.524, 1.834], "rad"],
   "args": [
     [ ["q", 0], ["q", 1], ["q", 2], ["q", 3] ]
   ],
diff --git a/schema.json b/schema.json
index f3fcf70..44d9d57 100644
--- a/schema.json
+++ b/schema.json
@@ -528,26 +528,23 @@
         "angles": {
           "anyOf": [
             {
-              "items": {
-                "anyOf": [
-                  {
+              "maxItems": 2,
+              "minItems": 2,
+              "prefixItems": [
+                {
+                  "items": {
                     "type": "number"
                   },
-                  {
-                    "maxItems": 2,
-                    "minItems": 2,
-                    "prefixItems": [
-                      {
-                        "type": "number"
-                      },
-                      {
-                        "const": "pi"
-                      }
-                    ],
-                    "type": "array"
-                  }
-                ]
-              },
+                  "type": "array"
+                },
+                {
+                  "enum": [
+                    "rad",
+                    "pi"
+                  ],
+                  "type": "string"
+                }
+              ],
               "type": "array"
             },
             {