Move most setup.py content into pyproject.toml

The modern approach is to put more things into `pyproject.toml`. This
moves most things out of `setup.py`, with the exception of the native
code extensions parts, and the version number. (Still to do: figure out
how to move the version number too.)

Author: mhucka

pyproject.toml

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 [build-system]
+build-backend = "setuptools.build_meta"
 requires = [
   "packaging",
   "setuptools>=78.1.1",
@@ -21,15 +22,20 @@ requires = [
   # "pip install" from sources needs to build Pybind, which needs CMake too.
   "cmake~=3.28.1",
 ]
-build-backend = "setuptools.build_meta"
 
 [project]
 name = "qsimcirq"
 version = "0.23.0.dev0"
-description = "Schrödinger and Schrödinger-Feynman simulators for quantum circuits."
+description = "High-performance quantum circuit simulator for C++ and Python."
+authors = [
+    { name = "The qsim/qsimh Developers", email = "[email protected]" }
+]
+maintainers = [
+    { name = "Google Quantum AI", email = "[email protected]" }
+]
+license = "Apache-2.0"
+requires-python = ">=3.10.0"
 readme = "README.md"
-authors = [{ name = "The qsim/qsimh Developers", email = "[email protected]" }]
-license = { text = "Apache-2.0" }
 classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Environment :: GPU :: NVIDIA CUDA",
@@ -71,16 +77,12 @@ keywords = [
     "state vector simulator",
     "software development kit",
 ]
-requires-python = ">=3.10.0"
 dependencies = [
     "absl-py",
     "cirq-core~=1.0",
     "numpy>=1.26.0",
 ]
 
-[project.urls]
-Homepage = "https://github.com/quantumlib/qsim"
-
 [project.optional-dependencies]
 dev = [
     "cmake~=3.28.1",
@@ -95,6 +97,13 @@ dev = [
     "setuptools>=78.1.1",
 ]
 
+[project.urls]
+homepage = "https://quantumai.google/qsim"
+documentation = "https://quantumai.google/qsim"
+source = "https://github.com/quantumlib/qsim"
+download = "https://pypi.org/project/qsimcirq/#files"
+tracker = "https://github.com/quantumlib/qsim/issues"
+
 [tool.setuptools]
 packages = ["qsimcirq"]
 package-data = {"qsimcirq" = ["py.typed"]}
@@ -120,3 +129,11 @@ skip = "*musllinux*"
 [tool.black]
 target-version = ['py310', 'py311', 'py312', 'py313']
 extend-exclude = 'third_party'
+
+[tool.isort]
+profile = 'black'
+order_by_type = false  # Sort alphabetically, irrespective of case.
+skip_gitignore = true
+combine_as_imports = true
+known_first_party = ["cirq*"]
+extend_skip = ["__init__.py"]

setup.py

@@ -23,9 +23,6 @@
 from setuptools import Extension, setup
 from setuptools.command.build_ext import build_ext
 
-# This file is largely based on the setup.py file at
-# https://github.com/pybind/cmake_example/blob/master/setup.py
-
 __version__ = "0.23.0.dev0"