[change] extracted plotting and started new module for plotting; improved docstring quality

pylot/core/util/pdf.py

@@ -363,6 +363,18 @@ class ProbabilityDensityFunction(object):
         return m
 
     def quantile_distance(self, prob_value):
+        """
+        takes a probability value and and returns the distance
+        between two complementary quantiles
+
+        .. math::
+
+            QA_\alpha = Q(1 - \alpha) - Q(\alpha)
+
+        :param value: probability value :math:\alpha
+        :type  value: float
+        :return: quantile distance
+        """
         if 0 >= prob_value or prob_value >= 0.5:
             raise ValueError('Value out of range.')
         ql = self.quantile(prob_value)
@@ -370,7 +382,20 @@ class ProbabilityDensityFunction(object):
         return qu - ql
 
 
-    def qtile_dist_quot(self,x):
+    def quantile_dist_frac(self, x):
+        """
+        takes a probability value and returns the fraction of two
+        corresponding quantile distances (
+        :func:`pylot.core.util.pdf.ProbabilityDensityFunction
+        #quantile_distance`)
+
+        .. math::
+
+            Q\Theta_\alpha = \frac{QA(0.5 - \alpha)}{QA(\alpha)}
+
+        :param value: probability value :math:\alpha
+        :return: quantile distance fraction
+        """
         if x <= 0 or x >= 0.25:
             raise ValueError('Value out of range.')
         return self.quantile_distance(0.5-x)/self.quantile_distance(x)

pylot/core/util/plotting.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import matplotlib.pyplot as plt
+
+def create_bin_list(l_boundary, u_boundary, nbins=100):
+    """
+    takes two boundaries and a number of bins and creates a list of bins for
+    histogram plotting
+    :param l_boundary: Any number.
+    :type  l_boundary: float
+    :param u_boundary: Any number that is greater than l_boundary.
+    :type  u_boundary: float
+    :param nbins: Any positive integer.
+    :type  nbins: int
+    :return: A list of equidistant bins.
+    """
+    if u_boundary <= l_boundary:
+        raise ValueError('Upper boundary must be greather than lower!')
+    elif nbins <= 0:
+        raise ValueError('Number of bins is not valid.')
+    binlist = []
+    for i in range(nbins):
+        binlist.append(l_boundary + i * (u_boundary - l_boundary) / nbins)
+    return binlist
+
+
+def histplot(array, binlist, xlab='Values',
+             ylab='Frequency', title=None, fnout=None):
+    """
+    function to quickly show some distribution of data. Takes array like data,
+    and a list of bins. Editing detail and inserting a legend is not possible.
+    :param array: List of values.
+    :type  array: Array like
+    :param binlist: List of bins.
+    :type  binlist: list
+    :param xlab: A label for the x-axes.
+    :type  xlab: str
+    :param ylab: A label for the y-axes.
+    :type  ylab: str
+    :param title: A title for the Plot.
+    :type  title: str
+    :param fnout: A path to save the plot instead of showing.
+                  Has to contain filename and type. Like: 'path/to/file.png'
+    :type  fnout. str
+    :return: -
+    """
+
+    plt.hist(array, bins=binlist)
+    plt.xlabel(xlab)
+    plt.ylabel(ylab)
+    if title:
+        plt.title(title)
+    if fnout:
+        plt.savefig(fnout)
+    else:
+        plt.show()