I have a new computer running Ubuntu 14.04 and Mathematica 10.0.02.0. I have a NVidia GTX 750ti video card.

I installed the latest 352.21 Nvidia drivers for this card, and tried installing CUDA 7 but was unable to get it to link to CUDA ;

Needs["CUDALink`"]

CUDAQ[]
Now shows false. The first time it downloaded some information.

It seemed the problem might be with directory paths; see; http://reference.wolfram.com/language/CUDALink/tutorial/Setup.html#10897850

This is the absolute path to the NVIDIA driver library.

The library is installed by the NVIDIA driver package downloaded from the NVIDIA driver download website.

"Linux-x86-64" "/usr/lib64/libnvidia-tls.so.*"

Default path to the NVIDIA driver library in case NVIDIADRIVERLIBRARY_PATH is not defined.

(the previewer is eliminating the underscores in NVIDIADRIVERLIBRARYPATH and CUDALIBRARY_PATH, I did enter them correctly)

I set in my .profile; NVIDIADRIVERLIBRARY_PATH=/usr/lib/nvidia-352/libnvidia-tls.so.352.21

This is the absolute path to the CUDA library. The library is installed by the NVIDIA driver package downloaded from the NVIDIA driver download website. "Linux-x86-64" "/usr/lib64/libcuda.so" Default path to the CUDA Library in case CUDALIBRARYPATH is not defined.

It appears CUDA 7 does not have a libcuda.so file, so I uninstalled CUDA 7 and tried CUDA 6.5, using the Ubuntu Software Center repository, I installed CUDA Toolkit 6.5 meta-package. libcuda.so (32.8k, 14 Sept 2014) is now in /usr/local/cuda-6.5/lib64/stubs, so I set my .profile

export PATH=/usr/local/cuda-6.5/bin:$PATH #CUDA

export LDLIBRARYPATH=/usr/local/cuda-6.5/lib64/stubs/libcuda.so:$LDLIBRARYPATH #LIBPATH

export NVIDIADRIVERLIBRARYPATH=/usr/lib/nvidia-352/libnvidia-tls.so.352.21:$LDLIBRARY_PATH #NVIDIA

Needs["CUDALink`"]

CUDAQ[]
gives false.