some tweaks to dockerfile and readme.

Dockerfile

@@ -1,31 +1,16 @@
-ARG BASE_CONTAINER=jupyter/base-notebook
+ARG BASE_CONTAINER=python:3.7
 FROM $BASE_CONTAINER
 
 USER root
 
 # Install all OS dependencies for fully functional notebook server
 RUN apt-get update && apt-get install -yq --no-install-recommends \
     build-essential \
-    emacs \
     git \
-    inkscape \
-    jed \
-    libsm6 \
-    libxext-dev \
-    libxrender1 \
-    lmodern \
     netcat \
-    pandoc \
     python-dev \
-    texlive-fonts-extra \
-    texlive-fonts-recommended \
-    texlive-generic-recommended \
-    texlive-latex-base \
-    texlive-latex-extra \
-    texlive-xetex \
     tzdata \
     unzip \
-    nano \
     make \
     cmake \
     curl \
@@ -60,14 +45,8 @@ RUN cd .. && /bin/rm -Rf LAGraph
 
 RUN ldconfig
 
-RUN conda install -yq datashader pytest ipdb
-
 ADD . /pygraphblas
 WORKDIR /pygraphblas
 # RUN python setup.py clean
 RUN python setup.py develop
-RUN pip install pytest-cov
-RUN chown -R jovyan:users .
-
-# Switch back to jovyan to avoid accidental container runs as root
-USER $NB_UID
+RUN pip install ipython pytest ipdb pytest-cov

README.md

@@ -4,40 +4,17 @@ SuitSparse:GraphBLAS for Python
 
 # Install
 
-pygraphblas for now involves building packages from source and
-requires Python 3.7 or higher.  For simple setup, a Dockerfile is
-provided that builds a complete pygraphblas environment based on the
-[Jupyer Base Notebook
-image](https://hub.docker.com/r/jupyter/base-notebook/).  To build a
-new container, run:
+pygraphblas is distributed as a docker image on [Docker
+Hub](https://cloud.docker.com/repository/docker/pygraphblas/pygraphblas/general)
+and can be run with a single command:
 
-    docker build . -t pygraphblas
-
-This will tag the new container as `pygraphblas`.  Change that if you
-want.  Next run the tests:
-
-    $ docker run -it pygraphblas pytest
-    ============================= test session starts ==============================
-    platform linux -- Python 3.7.3, pytest-5.0.1, py-1.8.0, pluggy-0.12.0
-    rootdir: /pygraphblas, inifile: setup.cfg
-    collected 47 items
-
-    tests/test_matrix.py .............................                       [ 61%]
-    tests/test_vector.py ..................                                  [100%]
-
-    ========================== 47 passed in 0.36 seconds ===========================
-
-This means pygraphblas is ready to go.  An interactive ipython
-session can be run to play with it:
-
-    $ docker run -it pygraphblas ipython
+    docker run -it pygraphblas/pygraphblas ipython
     Python 3.7.3 | packaged by conda-forge | (default, Jul  1 2019, 21:52:21)
     Type 'copyright', 'credits' or 'license' for more information
     IPython 7.6.1 -- An enhanced Interactive Python. Type '?' for help.
 
-
     In [1]: from pygraphblas import Matrix
-    
+
     # two random 3x3 matrices with 3 random values mod(10)
 
     In [3]: m = Matrix.from_random(int, 3, 3, 3).apply(lambda x: mod(x, 10))
@@ -52,6 +29,22 @@ session can be run to play with it:
     In [6]: n.to_lists()
     Out[6]: [[0, 1], [0, 0], [0, 35]] # only two values in sparse 3x3
 
+Next run the tests:
+
+    $ docker run -it pygraphblas/pygraphblas pytest
+    ========================================== test session starts ==========================================
+    platform linux -- Python 3.7.3, pytest-5.0.1, py-1.8.0, pluggy-0.12.0
+    rootdir: /pygraphblas, inifile: setup.cfg
+    plugins: cov-2.7.1
+    collected 54 items
+
+    tests/test_demo.py .                                                                              [  1%]
+    tests/test_matrix.py ...............................                                              [ 59%]
+    tests/test_scalar.py ....                                                                         [ 66%]
+    tests/test_vector.py ..................                                                           [100%]
+
+    ======================================= 54 passed in 1.04 seconds =======================================
+
 # Summary
 
 pygraphblas is a python extension that bridges [The GraphBLAS
@@ -185,9 +178,9 @@ multiplication syntax:
     from pygraphblas import Matrix, Vector
     from pygraphblas.semiring import min_plus_int64
     from pygraphblas.binaryop import min_int64, Accum
-    
+
     def sssp(matrix, start):
-        v = Vector.from_type(                  # create a vector 
+        v = Vector.from_type(                  # create a vector
             matrix.gb_type,                    # same type as m
             matrix.nrows                       # same size as rows of m
         )
@@ -200,23 +193,23 @@ multiplication syntax:
                 if w == v:                     # if nothing changed
                     break                      # exit early
             return v
-            
+
 An identical but slightly more verbose approach is to call the
 multiplication method directly `Vector.vxm' in this case, with
 explicit semiring and accumulator operations:
 
     def sssp_direct(matrix, start):
-        v = Vector.from_type(            # create a vector 
+        v = Vector.from_type(            # create a vector
             matrix.gb_type,              # same type as m
             matrix.nrows                 # same size as rows of m
         )
         v[start] = 0                     # set the starting vertext distance
 
         for _ in range(matrix.nrows):    # for every row in m:
             w = Vector.dup(v)            # dup the vector
-            v.vxm(                       # multiply vector by matrix 
+            v.vxm(                       # multiply vector by matrix
                 matrix, out=v,
-                semiring=min_plus_int64, # with min_plus, 
+                semiring=min_plus_int64, # with min_plus,
                 accum=min_int64          # acccumulate the minimum
             )
             if w == v:                   # if nothing changed