COMPASS

h1. CArMA

CArMA is the C++ API for Massively parallel Applications. It provides a set of C++ classes for an easy integration of GPU accelerated numerical tools into complex applications.

CArMA is built on top of the CUDA toolkit from NVIDIA. CUDA provides a large collection of tools to perform scientific computing (CuFFT, CuBLAS, CuRAND). Moreover, several libraries like MAGMA have been developed using CUDA and provide additional features very useful for scientific computing. 

!{width:70%}https://projets-lesia.obspm.fr/attachments/download/696/carma.png!

The goal of CArMA is to provide an easy access to rather low level GPU features through the use of C++ classes. 3 classes are used to control the CUDA context: 

* the CArMA device providing information on a specific device

* the CArMA context itself, regrouping the information about the overall system configuration

* the CArMA streams, containers for a collection of wrappers to CUDA streams

CArMA provides also 2 main classes for the handling of data on the GPU memory and the system memory:

* the CArMA object providing a container for the manipulation of data on the GPU

* the CArMA host object, providing a container for data on the system memory tagged and aligned so as to be accessed by the GPU DMA engine

Additionally, CArMA provides a set of wrappers to various libraries part of or based on the CUDA toolkit to manipulate CArMA objects and perform optimized computations.