# FindCUDAToolkit

This script locates the NVIDIA CUDA toolkit and the associated libraries, but does not require the `CUDA` language be enabled for a given project. This module does not search for the NVIDIA CUDA Samples.

## Search Behavior

Finding the CUDA Toolkit requires finding the `nvcc` executable, which is searched for in the following order:

1. If the `CUDA` language has been enabled we will use the directory containing the compiler as the first search location for `nvcc`.

2. If the `CUDAToolkit_ROOT` cmake configuration variable (e.g., `-DCUDAToolkit_ROOT=/some/path`) or environment variable is defined, it will be searched. If both an environment variable and a configuration variable are specified, the configuration variable takes precedence.

   The directory specified here must be such that the executable `nvcc` can be found underneath the directory specified by `CUDAToolkit_ROOT`. If `CUDAToolkit_ROOT` is specified, but no `nvcc` is found underneath, this package is marked as not found. No subsequent search attempts are performed.

3. If the CUDA_PATH environment variable is defined, it will be searched.

4. The user’s path is searched for `nvcc` using `find_program()`. If this is found, no subsequent search attempts are performed. Users are responsible for ensuring that the first `nvcc` to show up in the path is the desired path in the event that multiple CUDA Toolkits are installed.

5. On Unix systems, if the symbolic link `/usr/local/cuda` exists, this is used. No subsequent search attempts are performed. No default symbolic link location exists for the Windows platform.

6. The platform specific default install locations are searched. If exactly one candidate is found, this is used. The default CUDA Toolkit install locations searched are:

   Platform | Search Pattern
   --- | ---
   macOS | `/Developer/NVIDIA/CUDA-X.Y`
   Other Unix | `/usr/local/cuda-X.Y`
   Windows | `C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\vX.Y`

   Where `X.Y` would be a specific version of the CUDA Toolkit, such as `/usr/local/cuda-9.0` or `C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v9.0`

   Note

   When multiple CUDA Toolkits are installed in the default location of a system (e.g., both `/usr/local/cuda-9.0` and `/usr/local/cuda-10.0` exist but the `/usr/local/cuda` symbolic link does not exist), this package is marked as not found.

   There are too many factors involved in making an automatic decision in the presence of multiple CUDA Toolkits being installed. In this situation, users are encouraged to either (1) set `CUDAToolkit_ROOT` or (2) ensure that the correct `nvcc` executable shows up in `$PATH` for `find_program()` to find.

## Options

`VERSION`

  If specified, describes the version of the CUDA Toolkit to search for.

`REQUIRED`

  If specified, configuration will error if a suitable CUDA Toolkit is not found.

`QUIET`

  If specified, the search for a suitable CUDA Toolkit will not produce any messages.

`EXACT`

  If specified, the CUDA Toolkit is considered found only if the exact `VERSION` specified is recovered.

## Imported targets

An imported target named `CUDA::toolkit` is provided.

This module defines `IMPORTED` targets for each of the following libraries that are part of the CUDAToolkit:

- CUDA Runtime Library

- CUDA Driver Library

- cuBLAS

- cuFFT

- cuRAND

- cuSOLVER

- cuSPARSE

- cuPTI

- NPP

- nvBLAS

- nvGRAPH

- nvJPEG

- nvidia-ML

- nvRTC

- nvToolsExt

- OpenCL

- cuLIBOS

### CUDA Runtime Library

The CUDA Runtime library (cudart) are what most applications will typically need to link against to make any calls such as cudaMalloc, and cudaFree.

Targets Created:

- `CUDA::cudart`

- `CUDA::cudart_static`

### CUDA Driver Library

The CUDA Driver library (cuda) are used by applications that use calls such as cuMemAlloc, and cuMemFree. This is generally used by advanced

Targets Created:

- `CUDA::cuda_driver`

- `CUDA::cuda_driver`

### cuBLAS

The cuBLAS library.

Targets Created:

- `CUDA::cublas`

- `CUDA::cublas_static`

### cuFFT

The cuFFT library.

Targets Created:

- `CUDA::cufft`

- `CUDA::cufftw`

- `CUDA::cufft_static`

- `CUDA::cufftw_static`

### cuRAND

The cuRAND library.

Targets Created:

- `CUDA::curand`

- `CUDA::curand_static`

### cuSOLVER

The cuSOLVER library.

Targets Created:

- `CUDA::cusolver`

- `CUDA::cusolver_static`

### cuSPARSE

The cuSPARSE library.

Targets Created:

- `CUDA::cusparse`

- `CUDA::cusparse_static`

### cupti

The NVIDIA CUDA Profiling Tools Interface.

Targets Created:

- `CUDA::cupti`

- `CUDA::cupti_static`

### NPP

The NPP libraries.

Targets Created:

- nppc:

  - `CUDA::nppc`

  - `CUDA::nppc_static`

- nppial: Arithmetic and logical operation functions in nppi_arithmetic_and_logical_operations.h

  - `CUDA::nppial`

  - `CUDA::nppial_static`

- nppicc: Color conversion and sampling functions in nppi_color_conversion.h

  - `CUDA::nppicc`

  - `CUDA::nppicc_static`

- nppicom: JPEG compression and decompression functions in nppi_compression_functions.h

  - `CUDA::nppicom`

  - `CUDA::nppicom_static`

- nppidei: Data exchange and initialization functions in nppi_data_exchange_and_initialization.h

  - `CUDA::nppidei`

  - `CUDA::nppidei_static`

- nppif: Filtering and computer vision functions in nppi_filter_functions.h

  - `CUDA::nppif`

  - `CUDA::nppif_static`

- nppig: Geometry transformation functions found in nppi_geometry_transforms.h

  - `CUDA::nppig`

  - `CUDA::nppig_static`

- nppim: Morphological operation functions found in nppi_morphological_operations.h

  - `CUDA::nppim`

  - `CUDA::nppim_static`

- nppist: Statistics and linear transform in nppi_statistics_functions.h and nppi_linear_transforms.h

  - `CUDA::nppist`

  - `CUDA::nppist_static`

- nppisu: Memory support functions in nppi_support_functions.h

  - `CUDA::nppisu`

  - `CUDA::nppisu_static`

- nppitc: Threshold and compare operation functions in nppi_threshold_and_compare_operations.h

  - `CUDA::nppitc`

  - `CUDA::nppitc_static`

- npps:

  - `CUDA::npps`

  - `CUDA::npps_static`

### nvBLAS

The nvBLAS libraries. This is a shared library only.

Targets Created:

- `CUDA::nvblas`

### nvGRAPH

The nvGRAPH library.

Targets Created:

- `CUDA::nvgraph`

- `CUDA::nvgraph_static`

### nvJPEG

The nvJPEG library. Introduced in CUDA 10.

Targets Created:

- `CUDA::nvjpeg`

- `CUDA::nvjpeg_static`

### nvRTC

The nvRTC (Runtime Compilation) library. This is a shared library only.

Targets Created:

- `CUDA::nvrtc`

### nvidia-ML

The NVIDIA Management Library. This is a shared library only.

Targets Created:

- `CUDA::nvml`

### nvToolsExt

The NVIDIA Tools Extension. This is a shared library only.

Targets Created:

- `CUDA::nvToolsExt`

### OpenCL

The NVIDIA OpenCL Library. This is a shared library only.

Targets Created:

- `CUDA::OpenCL`

### cuLIBOS

The cuLIBOS library is a backend thread abstraction layer library which is static only. The `CUDA::cublas_static`, `CUDA::cusparse_static`, `CUDA::cufft_static`, `CUDA::curand_static`, and (when implemented) NPP libraries all automatically have this dependency linked.

Target Created:

- `CUDA::culibos`

Note: direct usage of this target by consumers should not be necessary.

## Result variables

`CUDAToolkit_FOUND`

  A boolean specifying whether or not the CUDA Toolkit was found.

`CUDAToolkit_VERSION`

  The exact version of the CUDA Toolkit found (as reported by `nvcc --version`).

`CUDAToolkit_VERSION_MAJOR`

  The major version of the CUDA Toolkit.

`CUDAToolkit_VERSION_MAJOR`

  The minor version of the CUDA Toolkit.

`CUDAToolkit_VERSION_PATCH`

  The patch version of the CUDA Toolkit.

`CUDAToolkit_BIN_DIR`

  The path to the CUDA Toolkit library directory that contains the CUDA executable `nvcc`.

`CUDAToolkit_INCLUDE_DIRS`

  The path to the CUDA Toolkit `include` folder containing the header files required to compile a project linking against CUDA.

`CUDAToolkit_LIBRARY_DIR`

  The path to the CUDA Toolkit library directory that contains the CUDA Runtime library `cudart`.

`CUDAToolkit_TARGET_DIR`

  The path to the CUDA Toolkit directory including the target architecture when cross-compiling. When not cross-compiling this will be equivalant to `CUDAToolkit_ROOT_DIR`.

`CUDAToolkit_NVCC_EXECUTABLE`

  The path to the NVIDIA CUDA compiler `nvcc`. Note that this path may not be the same as `CMAKE_CUDA_COMPILER`. `nvcc` must be found to determine the CUDA Toolkit version as well as determining other features of the Toolkit. This variable is set for the convenience of modules that depend on this one.