NumPy-QuadDType

A cross-platform Quad (128-bit) float Data-Type for NumPy.

Installation

pip install numpy
pip install numpy-quaddtype

Usage

import numpy as np
from numpy_quaddtype import QuadPrecDType, QuadPrecision

# using sleef backend (default)
np.array([1,2,3], dtype=QuadPrecDType())
np.array([1,2,3], dtype=QuadPrecDType("sleef"))

# using longdouble backend
np.array([1,2,3], dtype=QuadPrecDType("longdouble"))

Installation from source

Prerequisites

• gcc/clang

• CMake (≥3.15)

• Python 3.10+

• Git

• NumPy >= 2.4 (build from source)

Linux/Unix/macOS

Building the numpy-quaddtype package:

# setup the virtual env
python3 -m venv temp
source temp/bin/activate

# Install the package
pip install numpy pytest meson-python

# To build without QBLAS (default for MSVC)
# export CFLAGS="-DDISABLE_QUADBLAS"
# export CXXFLAGS="-DDISABLE_QUADBLAS"

python -m pip install . -v --no-build-isolation

# Run the tests
cd ..
python -m pytest/quaddtype/tests/

Windows

Prerequisites

• Visual Studio 2017 or later (with MSVC compiler)

• CMake (≥3.15)

• Python 3.10+

• Git

Step-by-Step Installation

1. Setup Development Environment

   Open a Developer Command Prompt for VS or Developer PowerShell for VS to ensure MSVC is properly configured.

2. Setup Python Environment

   # Create and activate virtual environment
   python -m venv numpy_quad_env
   .\numpy_quad_env\Scripts\Activate.ps1
   
   # Install build dependencies
   pip install -U pip
   pip install numpy pytest ninja meson
   

3. Set Environment Variables

   # Note: QBLAS is disabled on Windows due to MSVC compatibility issues
   $env:CFLAGS = "/DDISABLE_QUADBLAS"
   $env:CXXFLAGS = "/DDISABLE_QUADBLAS"
   

4. Build and Install numpy-quaddtype

   # Build and install the package
   python -m pip install . -v --no-build-isolation
   

5. Test Installation

   # Run tests
   pytest -s ..\quaddtype\tests\
   

6. QBLAS Disabled: QuadBLAS optimization is automatically disabled on Windows builds due to MSVC compatibility issues. This is handled by the -DDISABLE_QUADBLAS compiler flag.

7. Visual Studio Version: The instructions assume Visual Studio 2022. For other versions, adjust the generator string:

   • VS 2019: "Visual Studio 16 2019"

   • VS 2017: "Visual Studio 15 2017"

8. Architecture: The instructions are for x64. For x86 builds, change -A x64 to -A Win32.

Building with ThreadSanitizer (TSan)

This is a development feature to help detect threading issues. To build numpy-quaddtype with TSan enabled, follow these steps:

Use of clang is recommended with machine NOT supporting libquadmath (like ARM64). Set the compiler to clang/clang++ before proceeding.

export CC=clang
export CXX=clang++

1. Compile free-threaded CPython with TSan support. Follow the Python Free-Threading Guide for detailed instructions.

2. Create and activate a virtual environment using the TSan-enabled Python build.

3. Installing dependencies:

python -m pip install meson meson-python wheel ninja
# Need NumPy built with TSan as well
python -m pip install "numpy @ git+https://github.com/numpy/numpy" -C'setup-args=-Db_sanitize=thread'

4. Building SLEEF with TSan:

# clone the repository
git clone -b 3.8 https://github.com/shibatch/sleef.git
cd sleef

# Build SLEEF with TSan
cmake \
-DCMAKE_C_COMPILER=clang \
-DCMAKE_CXX_COMPILER=clang++ \
-DCMAKE_C_FLAGS="-fsanitize=thread -g -O1" \
-DCMAKE_CXX_FLAGS="-fsanitize=thread -g -O1" \
-DCMAKE_EXE_LINKER_FLAGS="-fsanitize=thread" \
-DCMAKE_SHARED_LINKER_FLAGS="-fsanitize=thread" \
-DSLEEF_BUILD_QUAD=ON \
-DSLEEF_BUILD_TESTS=OFF \
-S . -B build

cmake --build build -j

# Install the built library and headers into the system path (/usr/local)
sudo cmake --install build --prefix=/usr/local

5. Build and install numpy-quaddtype with TSan:

# SLEEF is already installed with TSan, we need to provide proper flags to numpy-quaddtype's meson file
# So that it does not build SLEEF again and use the installed one.

export CFLAGS="-fsanitize=thread -g -O0" 
export CXXFLAGS="-fsanitize=thread -g -O0"
export LDFLAGS="-fsanitize=thread"
python -m pip install . -vv --no-build-isolation -Csetup-args=-Db_sanitize=thread