[python][sampling] add box point sampler allowing for custom distros

python/frackit/sampling/__init__.py

 from ._sampling import *
+
+
+class BoxPointSampler:
+    """Class to sample random points within a box."""
+
+    def __init__(self, samplerX, samplerY, samplerZ):
+        """Create the sampler from random variable samplers for the coordinate directions."""
+        self.samplerX = samplerX
+        self.samplerY = samplerY
+        self.samplerZ = samplerZ
+
+    def sample(self):
+        x = self.samplerX()
+        y = self.samplerY()
+        z = self.samplerZ()
+
+        from frackit.geometry import Point_3
+        return Point_3(x, y, z)
+
+# creator for a uniform sampler within an interval
+def uniformIntervalSamplerCreator():
+    def makeSampler(min, max):
+        import random
+        def doSample():
+            return random.uniform(min, max)
+        return doSample
+    return makeSampler
+
+def makeBoxPointSampler(box,
+                        samplerCreatorX=uniformIntervalSamplerCreator(),
+                        samplerCreatorY=uniformIntervalSamplerCreator(),
+                        samplerCreatorZ=uniformIntervalSamplerCreator()):
+    """Creates a BoxPointSampler using the provided creators for samplers on intervals.
+       The creators default to uniform interval sampler creators if nothing is specified."""
+
+    # make samplers
+    samplerX = samplerCreatorX(box.xMin(), box.xMax())
+    samplerY = samplerCreatorY(box.yMin(), box.yMax())
+    samplerZ = samplerCreatorZ(box.zMin(), box.zMax())
+
+    return BoxPointSampler(samplerX, samplerY, samplerZ)