Add casting from FlexFloat objects to float (#2)

* Add casting from `FlexFloat` objects to `float`

* Update `README.md`

* ci: Add build and tests

.github/workflows/ci.yaml

@@ -0,0 +1,25 @@
+# Copyright 2024 ETH Zurich and University of Bologna.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+name: Test PyFlexFloat library
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: Build and test package
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: "3.9"
+      - name: Build
+        run: pip install .
+      - name: Install requirements
+        run: pip install -r requirements.txt
+      - name: Test
+        run: ./test/test.py

README.md

@@ -1,25 +1,20 @@
 ## PyFlexFloat
 
-A Python wrapper around OPRECOMP's [FlexFloat](https://github.com/oprecomp/flexfloat) library.
+A Python wrapper around OPRECOMP's [FlexFloat](https://github.com/oprecomp/flexfloat) library, enabling arbitrary precision floating-point arithmetic emulation in Python.
 
 ## Installation
 
-Clone the repository:
-`
-git clone https://github.com/colluca/pyflexfloat.git
-`
+Simply install via pip:
+```
+pip install pyflexfloat
+```
 
-Enter the local repository folder:
-`
-cd pyflexfloat
-`
+For developers, you can create an editable installation, to test your changes to the source code:
+```
+pip install -e .
+```
 
-Install in your active Python environment:
-`
-pip install .
-`
-
-Test installation:
-`
+Test the installation:
+```
 ./test/test.py
-`
+```

pyflexfloat/FlexFloat.py

@@ -80,7 +80,7 @@ def __init__(self, desc, val=None):
             lib.ff_init(self.ptr, desc[0])
 
     def __str__(self):
-        return str(lib.ff_get_double(self.ptr))
+        return str(float(self))
 
     def _uniformize(self, other):
         """Ensures that `self` and `other` have compatible types.
@@ -193,6 +193,9 @@ def __neg__(self):
     def __abs__(self):
         return -self if self < 0 else self
 
+    def __float__(self):
+        return lib.ff_get_double(self.ptr)
+
     def sqrt(self):
         result = FlexFloat(self.desc)
         lib.ff_sqrt(result.ptr, self.ptr)

pyproject.toml

@@ -1,8 +1,7 @@
 [build-system]
 requires = [
-    "setuptools>=60",
+    "setuptools>=65.0",
     "setuptools-scm>=8.0",
-    "cmake_build_extension==0.5.2.dev15",
     "cffi"
 ]
 build-backend = "setuptools.build_meta"

requirements.txt

@@ -0,0 +1 @@
+numpy

setup.py

@@ -4,12 +4,11 @@
 #
 # Author: Luca Colagrande <[email protected]>
 import setuptools
-import cmake_build_extension
+from setuptools.command.build import build
 import subprocess
 from pathlib import Path
 
-
-class CMakeBuild(setuptools.command.build.build):
+class CMakeBuild(build):
 
 	def run(self):
 		# Required to generate "flexfloat_config.h"

test/test.py

@@ -69,6 +69,7 @@
 
     # Test FlexFloat initialization from bytes
     print('= FlexFloat(..., bytes) =')
+    a = FlexFloat('e5m2', 3.14)
     b = FlexFloat('e5m2', a.bits().to_bytes(1, 'big'))
     print(f'bits: {b.bitstring()}')
     print(f'hex: {hex(b.bits())}')
@@ -86,3 +87,13 @@
     print(f'a: {a}')
     print(f'-a: {-a}')
     print(f'abs(a): {abs(a)}')
+
+    # Casting
+    print('= Casting =')
+    A = np.random.rand(length).astype(np.float32)
+    B = ff.array(A, 'fp32')
+    C = B.astype(np.float32)
+    D = B.astype(np.float64)
+    E = B.astype(np.float16)
+    F = ff.array(A, 'fp16')
+    print(A, B, C, D, E, F)