Installation from Source¶

In most cases, you should not need to build CUDA-Q from source. For the best experience, we recommend using a container runtime to avoid conflicts with other software tools installed on the system. Note that Singularity or Docker rootless mode address common issue or concerns that are often the motivation for avoiding the use of containers. Singularity, for example, can be installed in a user folder and its installation does not require admin permissions; see this section for more detailed instructions on how to do that. Our installation guide also contains instructions for how to connect an IDE to a running container.

If you do not want use a container runtime, we also provide pre-built binaries for using CUDA-Q with C++. These binaries are built following the instructions in this guide and should work for you as long as your system meets the compatibility requirements listed under Prerequisites. To install them, please follow the instructions here.

If our pre-built packages are not a good option for you, e.g. because you would like to use CUDA-Q on an operating system that is not officially supported, please follow this guide carefully without skipping any steps to build and install CUDA-Q from source. The rest of this guide details system requirements during the build and after installation, and walks through the installation steps.

Note

CUDA-Q contains some components that are only included as pre-built binaries and not part of our open source repository. We are working on either open-sourcing these components or making them available as separate downloads in the future. Even without these components, almost all features of CUDA-Q will be enabled in a source build, though some pieces may be less performant. At this time, the multi-GPU state vector simulator backend will not be included if you build CUDA-Q from source.

Prerequisites¶

The following pre-requisites need to be satisfied both on the build system and on the host system, that is the system where the built CUDA-Q binaries will be installed and used.

Linux operating system. The instructions in this guide have been validated with the AlmaLinux 8 image that serves as the base image for the manylinux_2_28 image, and should work for the operating systems CentOS 8, Debian 11 and 12, Fedora 38, OpenSUSE/SLED/SLES 15.5, RHEL 8 and 9, Rocky 8 and 9, and Ubuntu 22.04. Other operating systems may work, but have not been tested.
Bash shell. The CUDA-Q build, install and run scripts expect to use /bin/bash.
GNU C library. Make sure that the version on the host system is the same one or newer than the version on the build system. Our own builds use version 2.28.
CPU with either x86-64 (x86-64-v3 architecture and newer) or ARM64 (ARM v8-A architecture and newer). Other architectures may work but are not tested and may require adjustments to the build instructions.
Needed only on the host system: NVIDIA GPU with Volta, Turing, Ampere, Ada, or Hopper architecture and Compute Capability 7+. Make sure you have the latest drivers installed for your GPU, and double check that the driver version listed by the nvidia-smi command is 470.57.02 or newer. You do not need to have a GPU available on the build system; the CUDA compiler needed for the build can be installed and used without a GPU.

We strongly recommend using a virtual environment for the build that includes only the tools and dependencies listed in this guide. If you have additional software installed, you will need to make sure that the build is linking against the correct libraries and versions.

Build Dependencies¶

In addition to the prerequisites listed above, you will need to install the following prerequisites in your build environment prior to proceeding with the build as described in the subsequent sections:

Python version 3.8 or newer: If you intend to build CUDA-Q with Python support, make sure the Python version on the build system matches the version on the host system. If you intend to only build the C++ support for CUDA-Q, the Python interpreter is required only for some of the LLVM build scripts and the Python version used for the build does not have to match the version on the host system.
Common tools: wget, git, unzip. The commands in the rest of this guide assume that these tools are present on the build system, but they can be replaced by other alternatives (such as, for example, manually going to a web page and downloading a file/folder).

The above prerequisites are no longer needed once CUDA-Q is built and do not need to be present on the host system.

Note

The CUDA-Q build scripts and the commands listed in the rest of this document assume you are using bash as the shell for your build.

In addition to installing the needed build dependencies listed above, make sure to set the following environment variables prior to proceeding:

export CUDAQ_INSTALL_PREFIX=/usr/local/cudaq
export CUQUANTUM_INSTALL_PREFIX=/usr/local/cuquantum
export CUTENSOR_INSTALL_PREFIX=/usr/local/cutensor
export LLVM_INSTALL_PREFIX=/usr/local/llvm
export BLAS_INSTALL_PREFIX=/usr/local/blas
export ZLIB_INSTALL_PREFIX=/usr/local/zlib
export OPENSSL_INSTALL_PREFIX=/usr/local/openssl
export CURL_INSTALL_PREFIX=/usr/local/curl

These environment variables must be set during the build. We strongly recommend that their value is set to a path that does not already exist; this will ensure that these components are built/installed as needed when building CUDA-Q. The configured paths can be chosen freely, but the paths specified during the build are also where the corresponding libraries will be installed on the host system. We are working on making this more flexible in the future.

Note

Please do not set LLVM_INSTALL_PREFIX to an existing directory; To avoid compatibility issues, it is important to use the same compiler to build the LLVM/MLIR dependencies from source as is later used to build CUDA-Q itself.

Note

If you are setting the CURL_INSTALL_PREFIX variable to an existing CURL installation (not recommended), please make sure the command curl --version lists HTTP and HTTPS as supported protocols. If these protocols are not listed, please instead set the CURL_INSTALL_PREFIX variable to a path that does not exist. In that case, a suitable library will be automatically built from source as part of building CUDA-Q.

If you deviate from the instructions below for installing one of the dependencies and instead install it, for example, via package manager, you will need to make sure that the installation path matches the path you set for the corresponding environment variable(s).

CUDA¶

Building CUDA-Q requires a full installation of the CUDA toolkit. The instructions are tested using version 11.8, but any CUDA 11 or 12 version should work, as long as the installed driver on the host system supports that CUDA version. We recommend using the latest CUDA version that is supported by your driver.

Download a suitable CUDA version following the installation guide for your platform in the online documentation linked on that page.

Within the tested AlmaLinux 8 environment, for example, the following commands install CUDA 11.8:

CUDA_VERSION=11.8
CUDA_DOWNLOAD_URL=https://developer.download.nvidia.com/compute/cuda/repos
# Go to the url above, set the variables below to a suitable distribution
# and subfolder for your platform, and uncomment the line below.
# DISTRIBUTION=rhel8 CUDA_ARCH_FOLDER=x86_64

dnf config-manager --add-repo "${CUDA_DOWNLOAD_URL}/${DISTRIBUTION}/${CUDA_ARCH_FOLDER}/cuda-${DISTRIBUTION}.repo"
dnf install -y --nobest --setopt=install_weak_deps=False \
    cuda-toolkit-$(echo ${CUDA_VERSION} | tr . -)

Toolchain¶

The compiler toolchain used for the build needs to support C++20 and must be a supported CUDA host compiler for the installed CUDA version. The following instructions have been tested with GCC-11 as your toolchain for building CUDA-Q. If you use a different compiler, we recommend using an OpenMP-enabled compiler. At this time, we actively test building with GCC 11 and 12, as well as with Clang 16. Other toolchains may be supported but have not been tested.

Within the tested AlmaLinux 8 environment, for example, the following commands install GCC 11:

GCC_VERSION=11
dnf install -y --nobest --setopt=install_weak_deps=False \
    gcc-toolset-${GCC_VERSION}

Independent on which compiler toolchain you installed, set the following environment variables to point to the respective compilers on your build system:

GCC_INSTALL_PREFIX=/opt/rh/gcc-toolset-11
export CXX="${GCC_INSTALL_PREFIX}/root/usr/bin/g++"
export CC="${GCC_INSTALL_PREFIX}/root/usr/bin/gcc"
export FC="${GCC_INSTALL_PREFIX}/root/usr/bin/gfortran"
export CUDACXX=/usr/local/cuda/bin/nvcc

The variables CC and CXX must be set for the CUDA-Q build.
A Fortran compiler is needed (only) to build the OpenSSL dependency; if you have an existing OpenSSL installation that you set the OPENSSL_INSTALL_PREFIX variable to, you can omit setting the FC environment variable.
To use GPU-acceleration in CUDA-Q, make sure to set CUDACXX to your CUDA compiler. If the CUDA compiler is not found when building CUDA-Q, some components and backends will be omitted automatically during the build.

Building CUDA-Q¶

This installation guide has been written for a specific version/commit of CUDA-Q. Make sure to obtain the source code for that version. Clone the CUDA-Q GitHub repository and checkout the appropriate branch, tag, or commit. Note that the build scripts assume that they are run from within a git repository, and merely downloading the source code as ZIP archive hence will not work.

Please follow the instructions in the respective subsection(s) to build the necessary components for using CUDA-Q from C++ and/or Python. After the build, check the build log printed to the console to confirm that all desired components have been built. In particular, look for a line “Looking for CUDA compiler” in the build output, and confirm that it found the installed CUDA compiler, and the correct host compiler is used.

Note

The CUDA-Q build will compile or omit optional components automatically depending on whether the necessary pre-requisites are found in the build environment. If you see a message that a component has been skipped, and/or the CUDA compiler is not properly detected, make sure you followed the instructions for installing the necessary prerequisites and build dependencies, and have set the necessary environment variables as described in this document.

C++ Support¶

From within the folder where you cloned the CUDA-Q repository, run the following command to build CUDA-Q:

CUDAQ_WERROR=false \
CUDAQ_PYTHON_SUPPORT=OFF \
CUDAHOSTCXX="$CXX" \
LDFLAGS='-static-libgcc -static-libstdc++' \
LLVM_PROJECTS='clang;lld;mlir' \
bash scripts/build_cudaq.sh -uv

Note that lld is primarily needed when the build or host system does not already have an existing default linker on its path; CUDA-Q supports the same linkers as clang does.

To easily migrate the built binaries to the host system, we recommend creating a self-extracting archive. To do so, download the makeself script(s) and move the necessary files to install into a separate folder using the command

mkdir -p cuda_quantum_assets/llvm/bin && mkdir -p cuda_quantum_assets/llvm/lib && \
mv "${LLVM_INSTALL_PREFIX}/bin/"clang* cuda_quantum_assets/llvm/bin/ && \
mv "${LLVM_INSTALL_PREFIX}/lib/"clang* cuda_quantum_assets/llvm/lib/ && \
mv "${LLVM_INSTALL_PREFIX}/bin/llc" cuda_quantum_assets/llvm/bin/llc && \
mv "${LLVM_INSTALL_PREFIX}/bin/lld" cuda_quantum_assets/llvm/bin/lld && \
mv "${LLVM_INSTALL_PREFIX}/bin/ld.lld" cuda_quantum_assets/llvm/bin/ld.lld && \
mv "${CUTENSOR_INSTALL_PREFIX}" cuda_quantum_assets && \
mv "${CUQUANTUM_INSTALL_PREFIX}" cuda_quantum_assets && \
mv "${CUDAQ_INSTALL_PREFIX}/build_config.xml" cuda_quantum_assets/build_config.xml && \
mv "${CUDAQ_INSTALL_PREFIX}" cuda_quantum_assets

You can then create a self-extracting archive with the command

./makeself.sh --gzip --sha256 --license cuda_quantum_assets/cudaq/LICENSE \
    cuda_quantum_assets install_cuda_quantum.$(uname -m) \
    "CUDA-Q toolkit for heterogeneous quantum-classical workflows" \
    bash cudaq/migrate_assets.sh -t /opt/nvidia/cudaq

Python Support¶

The most convenient way to enable Python support within CUDA-Q is to build a wheel that can then easily be installed using pip. To ensure the wheel can be installed on the host system, make sure to use the same Python version for the build as the one that is installed on the host system. To build the CUDA-Q Python wheel, you will need to install the following additional Python-specific tools:

Python development headers: The development headers for your Python version are installed in the way as you installed Python itself. If you installed Python via the package manager for your system, you may need to install an additional package to get the development headers. The package name is usually your python version followed by either a -dev or -devel suffix. If you are using a Conda environment, the necessary headers should already be installed.
Pip package manager: Make sure the pip module is enable for your Python version. We refer to the Python documentation for more information about installing/enabling pip.
Python modules: Install the additional modules numpy, build, auditwheel, and patchelf for your Python version, e.g. python3 -m pip install numpy build auditwheel patchelf.

From within the folder where you cloned the CUDA-Q repository, run the following command to build the CUDA-Q Python wheel:

bash scripts/install_prerequisites.sh && \
CUDAHOSTCXX="$CXX" \
python3 -m build --wheel

Note

A version identifier will be automatically assigned to the wheel based on the commit history. You can manually override this detection to give a more descriptive identifier by setting the environment variable SETUPTOOLS_SCM_PRETEND_VERSION to the desired value before building the wheel.

After the initial build, auditwheel is used to include dependencies in the wheel, if necessary, and correctly label the wheel. We recommend not including the CUDA runtime libraries and instead install them separately on the host system following the instructions in the next section. The following command builds the final wheel, not including CUDA dependencies:

CUDAQ_WHEEL="$(find . -name 'cuda_quantum*.whl')" && \
MANYLINUX_PLATFORM="$(echo ${CUDAQ_WHEEL} | grep -o '[a-z]*linux_[^\.]*' | sed -re 's/^linux_/manylinux_2_28_/')" && \
LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:$(pwd)/_skbuild/lib" \ 
python3 -m auditwheel -v repair ${CUDAQ_WHEEL} \
    --plat ${MANYLINUX_PLATFORM} \
    --exclude libcublas.so.11 \
    --exclude libcublasLt.so.11 \
    --exclude libcusolver.so.11 \
    --exclude libcutensor.so.2 \
    --exclude libcutensornet.so.2 \
    --exclude libcustatevec.so.1 \
    --exclude libcudart.so.11.0 

The command above will create a new wheel in the wheelhouse folder. This wheel can be installed on any compatible platform.

Note

You can confirm that the wheel is indeed compatible with your host platform by checking that the wheel tag (i.e. the file name ending of the .whl file) is listed under “Compatible Tags” when running the command python3 -m pip debug --verbose on the host.

Installation on the Host¶

Make sure your host system satisfies the Prerequisites listed above.

To use CUDA-Q with C++, you should also make sure that the C++ standard library is installed and discoverable on your host system. CUDA-Q supports the GNU C++ standard library (libstdc++), version 11 or newer. Other libraries may work but can cause issues in certain cases.
To use CUDA-Q with Python, you should have a working Python installation on the host system, including the pip package manager.

If you followed the instructions for building the CUDA-Q Python wheel, copy the built .whl file to the host system, and install it using pip; e.g.

pip install cuda_quantum*.whl

To install the necessary CUDA and MPI dependencies for some of the components, you can either follow the instructions on PyPI.org, replacing pip install cuda-quantum with the command above, or you can follow the instructions in the remaining sections of this document to customize and better optimize them for your host system.

If you followed the instructions for building the CUDA-Q C++ tools, copy the install_cuda_quantum file that you created to the host system, and install it by running the commands

sudo bash install_cuda_quantum.$(uname -m) --accept
. /opt/nvidia/cudaq/set_env.sh

This will extract the built assets and move them to the correct locations. The set_env.sh script in /opt/nvidia/cudaq defines the necessary environment variables to use CUDA-Q. To avoid having to set them manually every time a new shell is opened, we highly recommend adding the following lines to the /etc/profile file:

if [ -f /opt/nvidia/cudaq/set_env.sh ];
  . /opt/nvidia/cudaq/set_env.sh
fi

Note

CUDA-Q includes its own linker, specifically the LLD linker. You can customize which linker the nvq++ compiler uses by setting the NVQPP_LD_PATH environment variable; for example export NVQPP_LD_PATH=ld.

The remaining sections in this document list additional runtime dependencies that are not included in the migrated assets and are needed to use some of the CUDA-Q features and components.

CUDA Runtime Libraries¶

To use GPU-acceleration in CUDA-Q you will need to install the necessary CUDA runtime libraries. While not necessary, we recommend installing the complete CUDA toolkit like you did for the CUDA-Q build. If you prefer to only install the minimal set of runtime libraries, the following commands, for example, install the necessary packages for the AlmaLinux 8 environment:

CUDA_VERSION=11.8
CUDA_DOWNLOAD_URL=https://developer.download.nvidia.com/compute/cuda/repos
# Go to the url above, set the variables below to a suitable distribution
# and subfolder for your platform, and uncomment the line below.
# DISTRIBUTION=rhel8 CUDA_ARCH_FOLDER=x86_64

version_suffix=$(echo ${CUDA_VERSION} | tr . -)
dnf config-manager --add-repo "${CUDA_DOWNLOAD_URL}/${DISTRIBUTION}/${CUDA_ARCH_FOLDER}/cuda-${DISTRIBUTION}.repo"
dnf install -y --nobest --setopt=install_weak_deps=False \
    cuda-nvtx-${version_suffix} cuda-cudart-${version_suffix} \
    libcusolver-${version_suffix} libcublas-${version_suffix}

MPI¶

To work with all CUDA-Q backends, a CUDA-aware MPI installation is required. If you do not have an existing CUDA-aware MPI installation, you can build one from source. To do so, in addition to the CUDA runtime libraries listed above you will need to install the CUDA runtime development package (cuda-cudart-devel-${version_suffix} or cuda-cudart-dev-${version_suffix}, depending on your distribution).

The following commands build a sufficient CUDA-aware OpenMPI installation. To make best use of MPI, we recommend a more fully featured installation including additional configurations that fit your host system. The commands below assume you have the necessary prerequisites for the OpenMPI build installed on the build system. Within the tested AlmaLinux 8 environment, for example, the packages autoconf, libtool, flex, and make need to be installed.

OPENMPI_VERSION=4.1.4
OPENMPI_DOWNLOAD_URL=https://github.com/open-mpi/ompi

wget "${OPENMPI_DOWNLOAD_URL}/archive/v${OPENMPI_VERSION}.tar.gz" -O /tmp/openmpi.tar.gz
mkdir -p ~/.openmpi-src && tar xf /tmp/openmpi.tar.gz --strip-components 1 -C ~/.openmpi-src
rm -rf /tmp/openmpi.tar.gz && cd ~/.openmpi-src
./autogen.pl 
LDFLAGS=-Wl,--as-needed ./configure \
    --prefix=/usr/local/openmpi \
    --disable-getpwuid --disable-static \
    --disable-debug --disable-mem-debug --disable-event-debug \
    --disable-mem-profile --disable-memchecker \
    --without-verbs \
    --with-cuda=/usr/local/cuda
make -j$(nproc) 
make -j$(nproc) install
cd - && rm -rf ~/.openmpi-src

Confirm that you have a suitable MPI implementation installed. For OpenMPI and MPICH, for example, this can be done by compiling and running the following program:

// Compile and run with:
// ```
// mpic++ mpi_cuda_check.cpp -o check.x && mpiexec -np 1 ./check.x
// ```

#include "mpi.h"
#if __has_include("mpi-ext.h")
#include "mpi-ext.h"
#endif
#include <stdio.h>

int main(int argc, char *argv[]) {
  MPI_Init(&argc, &argv);
  int exit_code;
  if (MPIX_Query_cuda_support()) {
    printf("CUDA-aware MPI installation.\n");
    exit_code = 0;
  } else {
    printf("Missing CUDA support.\n");
    exit_code = 1;
  }
  MPI_Finalize();
  return exit_code;
}

Note

If you are encountering an error similar to “The value of the MCA parameter plm_rsh_agent was set to a path that could not be found”, please make sure you have an SSH Client installed or update the MCA parameter to another suitable agent. MPI uses SSH or RSH to communicate with each node unless another resource manager, such as SLURM, is used.

Different MPI implementations are supported via a plugin infrastructure in CUDA-Q. Once you have a CUDA-aware MPI installation on your host system, you can configure CUDA-Q to use it by activating the necessary plugin. Plugins for OpenMPI and MPICH are included in CUDA-Q and can be activated by setting the environment variable MPI_PATH to the MPI installation folder and then running the command

bash "${CUDA_QUANTUM_PATH}/distributed_interfaces/activate_custom_mpi.sh"

Note

To activate the MPI plugin for the Python support, replace ${CUDA_QUANTUM_PATH} with the path that is listed under “Location” when you run the command pip show cuda-quantum.

If you use a different MPI implementation than OpenMPI or MPICH, you will need to implement the necessary plugin interface yourself prior to activating the plugin with the command above.