在Ubuntu 14.0上使用LuaRocks在Torch7中安装cutorch时出错

我刚刚开始学习lua，这些天我一直在安装torch-7，在我安装cutorch时出现了一个错误：

weigq@weigq-Lenovo-G410:~/torch$ luarocks install cutorch
Installing https://raw.githubusercontent.com/torch/rocks/master/cutorch-scm-1.rockspec...
Using https://raw.githubusercontent.com/torch/rocks/master/cutorch-scm-1.rockspec... switching to 'build' mode
正克隆到 'cutorch'...
remote: Counting objects: 203, done.
remote: Compressing objects: 100% (158/158), done.
remote: Total 203 (delta 57), reused 86 (delta 43), pack-reused 0
接收对象中: 100% (203/203), 191.70 KiB | 185.00 KiB/s, done.
处理 delta 中: 100% (57/57), done.
检查连接... 完成。
cmake -E make_directory build && cd build && cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH="/home/weigq/torch/install/bin/.." -DCMAKE_INSTALL_PREFIX="/home/weigq/torch/install/lib/luarocks/rocks/cutorch/scm-1" && make -j$(getconf _NPROCESSORS_ONLN) install

-- The C compiler identification is GNU 4.8.4
-- The CXX compiler identification is GNU 4.8.4
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Found Torch7 in /home/weigq/torch/install
CMake Error at /usr/share/cmake-2.8/Modules/FindCUDA.cmake:548 (message):
  Specify CUDA_TOOLKIT_ROOT_DIR
Call Stack (most recent call first):
  CMakeLists.txt:7 (FIND_PACKAGE)

-- Configuring incomplete, errors occurred!
See also "/tmp/luarocks_cutorch-scm-1-8668/cutorch/build/CMakeFiles/CMakeOutput.log".

Error: Build error: Failed building.

我不知道该如何处理？有人能帮我解决一下吗？谢谢！