Merge branch 'rf/default-cuda-home' into 'master'

Rf/default cuda home

See merge request fsl/base!16

CHANGELOG.md

 # FSL base project changelog
 
 
+## 2107.3 (Monday 12th July 2021)
+
+ - Change CUDA build configuration so that now all is needed is for `nvcc` to
+   be on the `$PATH`, or a `$NVCC` variable to be set.
+
+
 ## 2107.2 (Sunday 11th July 2021)
 
  - Further tweaks to CUDA linking logic.

README.md

@@ -17,11 +17,17 @@ The `.ci` directory contains a collection of tests which validate the
 behaviour of various aspects of the `base` project. All tests are written
 in Python, and are executed with `pytest`.
 
-## CUDA build options
 
-The following options may be used to control compilation of a  CUDA project:
+## Building FSL CUDA projects.
+
+Some FSL projects (e.g. [`fsl/eddy`(https://git.fmrib.ox.ac.uk/fsl/eddy) use
+CUDA for GPU acceleration. In order to compile these projects, the `nvcc`
+compiler must be available on your `$PATH`, or a variable called `$NVCC` must
+refer to the `nvcc` executable to use.
+
+The following additional options may be used to control compilation of a CUDA
+project:
 
- - `CUDA_HOME`:    Specify the path to the CUDA installation directory
  - `CUDA_STATIC`:  Statically link against the CUDA runtime and certain;
                   CUDA Toolkit libraris (default is to use dynamic linking).
  - `GENCODEFLAGS`: `-gencode` options specifying the device architectures to
@@ -31,4 +37,8 @@ The following options may be used to control compilation of a  CUDA project:
 For example, to compile a CUDA project with a specific CUDA installation, and
 using static linking:
 
-    make CUDA_STATIC=1 CUDA_HOME=/usr/local/cuda-10.1
+    export PATH=/usr/local/cuda-10.2/bin:$PATH
+    make CUDA_STATIC=1
+
+The `Makefile` for each FSL CUDA project may provide additional options for
+controlling compilation.

config/buildSettings.mk

@@ -114,25 +114,17 @@ endif
 #####################################################################
 #
 # Default compiler commands, flags, and basic external libraries for
-# CUDA projects.
+# CUDA projects. nvcc must be on the $PATH, or $NVCC must be set.
 #
 #####################################################################
-
-ifneq ($(shell which nvcc), )
-
-  # NVCC, CUDA_HOME, CUDA_VER, GENCODEFLAGS,
-  # NVCCFLAGS, NVCCLDFLAGS, and CUDA_STATIC
-  # may be specified/overridden by the
-  # environment.
-
-  # We specifically use variable names "CUDA_VER"
-  # and "CUDA_HOME" because they will be set in
-  # the conda-forge CUDA build environment (and
-  # will take precedence over these definitions
-  # here when they are set).
-  NVCC         ?= nvcc
-  CUDA_HOME    ?= ${FSLDIR}
-  CUDA_VER     ?= $(shell nvcc --version | grep -Po "release \K[0-9\.]+")
+NVCC ?= $(shell which nvcc)
+ifneq (${NVCC}, )
+
+  # NVCC, GENCODEFLAGS, NVCCFLAGS, NVCCLDFLAGS,
+  # and CUDA_STATIC may be specified/overridden
+  # by the environment.
+  CUDA_HOME     = $(shell dirname ${NVCC})/../
+  CUDA_VER      = $(shell ${NVCC} --version | grep -Po "release \K[0-9\.]+")
   GENCODEFLAGS ?= $(shell ${FSLCONFDIR}/supportedGencodes.sh ${CUDA_VER})
 
   # We specify the compiler to use with -ccbin, as
@@ -151,6 +143,8 @@ ifneq ($(shell which nvcc), )
 
   # Link CUDA libraries statically, if compilation
   # was invoked with "make CUDA_STATIC=1".
+  # Compiler / linker options vary depending on the
+  # CUDA version
   _CUDALIBS = -lcuda
   ifdef CUDA_STATIC
     # The cuda/cudart/cudadevrt libs are handled by nvcc.
@@ -176,7 +170,11 @@ ifneq ($(shell which nvcc), )
     _CUDALIBS += $(subst -lcublas,${CUBLAS_STATIC}, \
                  $(subst -lcurand,-lcurand_static,${CUDALIBS}))
   else
-    NVCCFLAGS += --cudart=shared  --cudadevrt=static
-	_CUDALIBS += ${CUDALIBS}
+    ifeq ($(patsubst 9.%,,${CUDA_VER}),)
+      NVCCFLAGS += --cudart=shared
+    else
+      NVCCFLAGS += --cudart=shared --cudadevrt=static
+    endif
+    _CUDALIBS += ${CUDALIBS}
   endif
 endif