pygrass: Return always the Module instance and rename max_num_procs to nprocs to be more consistent with other GRASS libraries

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@61883 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/pygrass/modules/interface/module.py

@@ -2,6 +2,7 @@
 from __future__ import (nested_scopes, generators, division, absolute_import,
                         with_statement, print_function, unicode_literals)
 import sys
+from multiprocessing import cpu_count
 
 if sys.version_info[0] == 2:
     from itertools import izip_longest as zip_longest
@@ -39,12 +40,18 @@ class ParallelModuleQueue(object):
        >>> from grass.pygrass.modules import Module, ParallelModuleQueue
        >>> mapcalc_list = []
        >>> mapcalc = Module("r.mapcalc", overwrite=True, run_=False)
-       >>> queue = ParallelModuleQueue(max_num_procs=3)
+       >>> queue = ParallelModuleQueue(nprocs=3)
        >>> for i in xrange(5):
        ...     new_mapcalc = copy.deepcopy(mapcalc)
        ...     mapcalc_list.append(new_mapcalc)
        ...     new_mapcalc(expression="test_pygrass_%i = %i"%(i, i))
        ...     queue.put(new_mapcalc)
+       Module('r.mapcalc')
+       Module('r.mapcalc')
+       Module('r.mapcalc')
+       Module('r.mapcalc')
+       Module('r.mapcalc')
+
        >>> queue.wait()
        >>> for mapcalc in mapcalc_list:
        ...     print(mapcalc.popen.returncode)
@@ -55,15 +62,17 @@ class ParallelModuleQueue(object):
        0
 
     """
-    def __init__(self, max_num_procs=1):
+    def __init__(self, nprocs=1):
         """Constructor
 
-        :param max_num_procs: The maximum number of Module processes that
-                              can be run in parallel
-        :type max_num_procs: int
+        :param nprocs: The maximum number of Module processes that
+                          can be run in parallel, defualt is 1, if None
+                          then use all the available CPUs.
+        :type nprocs: int
         """
-        self._num_procs = int(max_num_procs)
-        self._list = int(max_num_procs) * [None]
+        nprocs = int(nprocs) if nprocs else cpu_count()
+        self._num_procs = nprocs
+        self._list = nprocs * [None]
         self._proc_count = 0
 
     def put(self, module):
@@ -111,15 +120,15 @@ class ParallelModuleQueue(object):
         """
         return self._num_procs
 
-    def set_max_num_procs(self, max_num_procs):
+    def set_max_num_procs(self, nprocs):
         """Set the maximum number of Module processes that should run
         in parallel
 
-        :param max_num_procs: The maximum number of Module processes that
+        :param nprocs: The maximum number of Module processes that
                               can be run in parallel
-        :type max_num_procs: int
+        :type nprocs: int
         """
-        self._num_procs = int(max_num_procs)
+        self._num_procs = int(nprocs)
         self.wait()
 
     def wait(self):
@@ -178,6 +187,7 @@ class Module(object):
 
         >>> new_neighbors2 = copy.deepcopy(neighbors)
         >>> new_neighbors2(input="mapD", size=3, run_=False)
+        Module('r.neighbors')
         >>> new_neighbors2.get_bash()
         u'r.neighbors input=mapD method=average size=3 quantile=0.5 output=mapB'
 
@@ -187,6 +197,7 @@ class Module(object):
 
         >>> new_neighbors3 = copy.deepcopy(neighbors)
         >>> new_neighbors3(input="mapA", size=3, output="mapB", run_=False)
+        Module('r.neighbors')
         >>> new_neighbors3.get_bash()
         u'r.neighbors input=mapA method=average size=3 output=mapB'
 
@@ -249,16 +260,21 @@ class Module(object):
         >>> colors.run()
         Module('r.colors')
         >>> colors(color="gyr")
+        Module('r.colors')
         >>> colors.run()
         Module('r.colors')
         >>> colors(color="ryg")
+        Module('r.colors')
         >>> colors(stderr_=PIPE)
+        Module('r.colors')
         >>> colors.run()
         Module('r.colors')
         >>> print(colors.outputs["stderr"].value.strip())
         Color table for raster map <test_a> set to 'ryg'
         >>> colors(color="byg")
+        Module('r.colors')
         >>> colors(stdout_=PIPE)
+        Module('r.colors')
         >>> colors.run()
         Module('r.colors')
         >>> print(colors.outputs["stderr"].value.strip())
@@ -403,7 +419,7 @@ class Module(object):
         """
         if not args and not kargs:
             self.run()
-            return
+            return self
         #
         # check for extra kargs, set attribute and remove from dictionary
         #
@@ -452,6 +468,7 @@ class Module(object):
                     msg = "Required parameter <%s> not set."
                     raise ParameterError(msg % k)
             return self.run()
+        return self
 
     def get_bash(self):
         """Return a BASH rapresentation of the Module."""