[python][samplers] use __call__ to be in agreement with c++ impl

Entities are sampled from sampler classes in the C++ code by calling the
operator(). In order to streamline the Python implementation, we used
the name __call__ in the python classes to get the same syntax.

appl/example1/example1.py

@@ -71,7 +71,7 @@ entities2 = []
 print("\n --- Start entity sampling ---\n")
 while not status.finished():
     # sample a quadrilateral, alternating between sampler 1 and sampler 2
-    quad = quadSampler1.sample() if sampleIntoSet1 else quadSampler2.sample()
+    quad = quadSampler1() if sampleIntoSet1 else quadSampler2()
     entitySet = entities1 if sampleIntoSet1 else entities2
     otherEntitySet = entities2 if sampleIntoSet1 else entities1
 

appl/example2/example2.py

@@ -78,7 +78,7 @@ entities2 = []
 print("\n --- Start entity sampling ---\n")
 while not status.finished():
     # sample a quadrilateral, alternating between sampler 1 and sampler 2
-    quad = quadSampler1.sample() if sampleIntoSet1 else quadSampler2.sample()
+    quad = quadSampler1() if sampleIntoSet1 else quadSampler2()
     entitySet = entities1 if sampleIntoSet1 else entities2
     otherEntitySet = entities2 if sampleIntoSet1 else entities1
 

appl/example3/example3.py

@@ -137,7 +137,7 @@ sampleIntoSet1 = True
 containedNetworkArea = 0.0;
 while not status.finished():
     id = diskSetId if sampleIntoSet1 else quadSetId
-    geom = diskSampler.sample() if sampleIntoSet1 else quadSampler.sample()
+    geom = diskSampler() if sampleIntoSet1 else quadSampler()
 
     # If the set this geometry belongs to is finished, skip the rest
     if status.finished(id):

frackit/python/sampling/boxpointsampler.hh

@@ -54,7 +54,7 @@ void registerBoxPointSampler(py::module& module)
             "distributionX"_a, "distributionY"_a, "distributionZ"_a);
 
     // register point sample function
-    cls.def("sample", &UniformSampler::operator(), "returns a randomly sampled point");
+    cls.def("__call__", &UniformSampler::operator(), "returns a randomly sampled point");
 }
 
 } // end namespace Frackit::Python

frackit/python/sampling/cylinderpointsampler.hh

@@ -56,7 +56,7 @@ void registerCylinderPointSampler(py::module& module)
             "cylinder"_a, "distributionR"_a, "distributionPhi"_a, "distributionH"_a);
 
     // register point sample function
-    cls.def("sample", &UniformSampler::operator(), "returns a randomly sampled point");
+    cls.def("__ca,,__", &UniformSampler::operator(), "returns a randomly sampled point");
 }
 
 } // end namespace Frackit::Python

python/frackit/sampling/__init__.py

@@ -17,7 +17,7 @@ class BoxPointSampler:
         self.samplerY = samplerY
         self.samplerZ = samplerZ
 
-    def sample(self):
+    def __call__(self):
         x = self.samplerX()
         y = self.samplerY()
         z = self.samplerZ()
@@ -48,7 +48,7 @@ class CylinderPointSampler:
         self.samplerPhi = samplerPhi
         self.samplerZ = samplerZ
 
-    def sample(self):
+    def __call__(self):
 
         from frackit.geometry import Vector_3
         a = Vector_3(self.cylinder.bottomFace().majorAxis());
@@ -161,7 +161,7 @@ class DiskSampler:
         self.yAngleSampler = yAngleSampler
         self.zAngleSampler = zAngleSampler
 
-    def sample(self):
+    def __call__(self):
 
         a = self.majAxisSampler()
         while (a <= 0.0): a = self.majAxisSampler()
@@ -193,7 +193,7 @@ class DiskSampler:
 
         # sample center point and make disk
         from frackit.geometry import Ellipse_3
-        ellipse = Ellipse_3(self.pointSampler.sample(),
+        ellipse = Ellipse_3(self.pointSampler(),
                             Direction_3(axes[0]),
                             Direction_3(axes[1]),
                             a, b)
@@ -221,7 +221,7 @@ class QuadrilateralSampler:
         self.edgeLengthSampler = edgeLengthSampler
         self.minEdgeLength = minEdgeLength
 
-    def sample(self):
+    def __call__(self):
 
         strike = self.strikeAngleSampler()
         dip = self.dipAngleSampler()
@@ -255,7 +255,7 @@ class QuadrilateralSampler:
         dyVec2 = Vector_3(deepcopy(axes[1].x()), deepcopy(axes[1].y()), deepcopy(axes[1].z())); dyVec2 *= dy2/2.0
 
         # compute corner points
-        c = self.pointSampler.sample()
+        c = self.pointSampler()
         from frackit.geometry import Point_3
         c1 = Point_3(deepcopy(c.x()), deepcopy(c.y()), deepcopy(c.z())); c1 -= dxVec1; c1 -= dyVec1
         c2 = Point_3(deepcopy(c.x()), deepcopy(c.y()), deepcopy(c.z())); c2 += dxVec1; c2 -= dyVec2