Add Singularity instructions to the FAQs.

Author: binarybottle

README.rst

@@ -71,8 +71,8 @@ We recommend installing Mindboggle and its dependencies as a cross-platform
 Docker container for greater convenience and reproducibility of results.
 All the examples below assume you are using this Docker container,
 with the path /home/jovyan/work/ pointing to your host machine.
-(Alternatively, Mindboggle can be installed from scratch on a Linux machine
-using
+(Alternatively, one can `create a Singularity image <faq>`_,
+or Mindboggle can be installed from scratch on a Linux machine using
 `this script <https://raw.githubusercontent.com/nipy/mindboggle/master/install_mindboggle.sh>`_).
 
 1. `Install and run Docker <https://docs.docker.com/engine/installation/>`_
@@ -87,7 +87,7 @@ terminal window)::
 over 6GB.*
 
 *Note 2: You may need to increase memory allocated by Docker to at least 5GB.
-For example: `By default, Docker for Mac is set to use 2 GB runtime memory <https://docs.docker.com/docker-for-mac/>`_.*
+For example:* `By default, Docker for Mac is set to use 2 GB runtime memory <https://docs.docker.com/docker-for-mac/>`_.
 
 3. Optionally download sample data. To try out the ``mindboggle`` examples
 below, download and unzip the directory of example input data

docs/faq.rst

@@ -11,3 +11,4 @@
    faq/citing_mindboggle
    faq/run_time
    labels
+   faq/singularity

docs/faq/singularity.rst

@@ -0,0 +1,27 @@
+.. _singularity:
+
+------------------------------------------------------------------------------
+ How do I create and use a Singularity image rather than Docker?
+------------------------------------------------------------------------------
+
+To convert the Mindboggle Docker image to a Singularity image, run::
+
+  singularity pull mindboggle.img docker://nipy/mindboggle
+
+After the conversion, you'll need 3 mounts (data, working directory, and
+home directory) for it to work. Here is an example of the full command
+together with some of the optional arguments, using the same
+environment variables as in the `README <http://mindboggle.info/software.html>`_::
+
+    singularity run \
+      -B $HOST:$DOCK:ro \
+      -B $PWD:$DOCK \
+      -B $PWD/jovyan:/home/jovyan \ 
+      -e mindboggle.img \
+      $DOCK/example_mri_data/T1.nii.gz \
+      --id arno \
+      --fs_T2image $DOCK/example_mri_data/T2.nii.gz \
+      --plugin MultiProc --plugin_args "dict(n_procs=2)" \
+      --fs_openmp 5 --ants_num_threads 5 --mb_num_threads 10
+
+Thanks, Satra!