Implemented a cuda autodetection feature in the build system. It is c…

…ompletely backwards compatible but if no options concerning cuda are given during the configure stage, it tries to find cuda in /usr/local/cuda.

configure.ac

@@ -405,61 +405,105 @@ AS_IF([test x$fftw_found = xyes],[
 ##################################
 # check for CUDA
 AC_MSG_CHECKING([whether to use CUDA])
+
 AC_ARG_WITH([cuda],
-	AS_HELP_STRING([--with-cuda=CUDAINSTALLDIR],[specify where CUDA is installed.
+	AS_HELP_STRING([--with-cuda[=CUDAINSTALLDIR]],[specify where CUDA is installed.
+	    Defaults to /usr/local/cuda.
 		The cuda compiler can also be specified by setting the NVCC
 		environment variable. The CUDA library and header can be
 		manually specified by using CPPFLAGS, LDFLAGS and LIBS.]),
-	, with_cuda=no)
+	, with_cuda=guess)
 AC_MSG_RESULT($with_cuda)
 
-if test x$with_cuda != xno; then
-   # if installation dir is given, set the paths
-   if test x$with_cuda != xyes; then
-       if test x$NVCC = x; then
-	   NVCC=$with_cuda/bin/nvcc
-       fi
-       if test -d $with_cuda/lib64; then
-           LDFLAGS="$LDFLAGS -L$with_cuda/lib64"
-       else
-	   LDFLAGS="$LDFLAGS -L$with_cuda/lib"
-       fi
-       NVCCFLAGS="$NVCCFLAGS -I$with_cuda/include"
-   fi
+if test x$with_cuda = xguess -o x$with_cuda = xyes; then
+   cuda_path=/usr/local/cuda
+elif test x$with_cuda != xno; then
+   cuda_path=$with_cuda
+   with_cuda=yes
+fi
 
-   # NVCC
-   AC_ARG_VAR(NVCC,[NVIDIA CUDA compiler command])
-   AC_ARG_VAR(NVCCFLAGS,[special compiler flags for the NVIDIA CUDA compiler])
-   AC_PATH_PROG(NVCC, nvcc, no)
-   if test x$NVCC = xno; then
-       AC_MSG_FAILURE([CUDA compiler nvcc was not found, specify location using the NVCC variable])
-   fi
+cuda_ok=no
 
-   # runtime library
-   AC_CHECK_LIB(cudart, cudaGetDevice, [LIBS="$LIBS -lcudart"], [AC_MSG_FAILURE([could not find cuda runtime library (cudart), specify location using LDFLAGS])])
+if test x$with_cuda != xno; then
+    cuda_ok=yes
+
+    if test x$NVCC = x; then
+        NVCC=$cuda_path/bin/nvcc
+    fi
+
+    if test -d $cuda_path/lib64; then
+        LDFLAGS="$LDFLAGS -L$cuda_path/lib64"
+    else
+        LDFLAGS="$LDFLAGS -L$cuda_path/lib"
+    fi
+
+    NVCCFLAGS="$NVCCFLAGS -I$cuda_path/include"
+
+    # NVCC
+    AC_ARG_VAR(NVCC,[NVIDIA CUDA compiler command])
+    AC_ARG_VAR(NVCCFLAGS,[special compiler flags for the NVIDIA CUDA compiler])
+    AC_PATH_PROG(NVCC, nvcc, no)
+
+    if test x$NVCC = xno; then
+        AC_MSG_FAILURE([CUDA compiler nvcc was not found, specify location using the NVCC variable])
+    fi
+
+    # libraries
+    AC_CHECK_LIB(cudart, cudaGetDevice, [LIBS="$LIBS -lcudart"], [
+        cuda_ok=no
+        
+        AS_IF([test x$with_cuda = xyes],[
+            AC_MSG_FAILURE([could not find cuda runtime library (cudart), specify location using LDFLAGS])
+        ],[
+            AC_MSG_WARN([could not find cuda runtime library (cudart). Some features will not be available!])
+        ])
+    ])
+
+    AC_CHECK_LIB(cufft, cufftPlan3d, [LIBS="$LIBS -lcufft"], [
+        cuda_ok=no
+        
+        AS_IF([test x$with_cuda = xyes],[
+            AC_MSG_FAILURE([could not find cuda FFT library (cufft), specify location using LDFLAGS])
+        ],[
+            AC_MSG_WARN([could not find cuda FFT library (cufft). Some features will not be available!])
+        ])
+    ])
 
-   # NVCC compile check
-   AC_MSG_CHECKING([whether CUDA works])
-   # if no other compute capability is defined by the user, we need at least 1.1
-   case "$NVCCFLAGS" in
+    # NVCC compile check
+    AC_MSG_CHECKING([whether CUDA works])
+
+    # if no other compute capability is defined by the user, we require at least 1.1
+    case "$NVCCFLAGS" in
        *-arch=*) ;;
-       *) NVCCFLAGS="$NVCCFLAGS --ptxas-options=-v -gencode arch=compute_11,code=compute_11 -gencode  arch=compute_20,code=compute_20"
-   esac
-   # use nvcc
-   save_CC=$CC
-   save_CFLAGS=$CFLAGS
-   # autoconf currently doesn't allow to define new languages like cuda, so try to work around it
-   CC=$NVCC
-   CFLAGS="$NVCCFLAGS"
-   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
-	#include <cuda.h>
-   ],[
-	cudaGetDevice(0);
-   ])], [AC_MSG_RESULT(yes)], [AC_MSG_FAILURE([cannot compile CUDA code. Look at config.log for more details.])])
-   CC=$save_CC
-   CFLAGS=$save_CFLAGS
-   AC_DEFINE(CUDA,[],[Whether CUDA is available])
+       *) NVCCFLAGS="$NVCCFLAGS --ptxas-options=-v -gencode arch=compute_11,code=compute_11 -gencode arch=compute_20,code=compute_20"
+    esac
+
+    # use nvcc
+    save_CC=$CC
+    save_CFLAGS=$CFLAGS
+
+    # autoconf currently doesn't allow to define new languages like cuda, this is a workaround
+    CC=$NVCC
+    CFLAGS="$NVCCFLAGS"
+
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <cuda.h>],[cudaGetDevice(0);])], [
+        AC_MSG_RESULT(yes)
+    ],[
+        cuda_ok=no
+        
+        AS_IF([test x$with_cuda = xyes],[
+            AC_MSG_FAILURE([cannot compile CUDA code. Look at config.log for more details.])
+        ],[
+            AC_MSG_WARN([cannot compile CUDA code. Some features will not be available!])
+        ])
+    ])
+
+    CC=$save_CC
+    CFLAGS=$save_CFLAGS
+
+    AC_DEFINE(CUDA,[],[Whether CUDA is available])
 fi
+
 AM_CONDITIONAL(CUDA, [test x$with_cuda != xno])
 
 cat <<EOF
@@ -593,7 +637,7 @@ dot			= $DOT
 python			= $PYTHON
 EOF
 
-if test x$with_cuda != xno; then
+if test x$cuda_ok = xyes; then
 cat <<EOF
 CUDA compiler		= $NVCC
 CUDA flags		= $NVCCFLAGS