Add vendored packages back

lib/spack/external/_vendoring/altgraph/GraphStat.py

@@ -0,0 +1,73 @@
+"""
+altgraph.GraphStat - Functions providing various graph statistics
+=================================================================
+"""
+
+
+def degree_dist(graph, limits=(0, 0), bin_num=10, mode="out"):
+    """
+    Computes the degree distribution for a graph.
+
+    Returns a list of tuples where the first element of the tuple is the
+    center of the bin representing a range of degrees and the second element
+    of the tuple are the number of nodes with the degree falling in the range.
+
+    Example::
+
+        ....
+    """
+
+    deg = []
+    if mode == "inc":
+        get_deg = graph.inc_degree
+    else:
+        get_deg = graph.out_degree
+
+    for node in graph:
+        deg.append(get_deg(node))
+
+    if not deg:
+        return []
+
+    results = _binning(values=deg, limits=limits, bin_num=bin_num)
+
+    return results
+
+
+_EPS = 1.0 / (2.0 ** 32)
+
+
+def _binning(values, limits=(0, 0), bin_num=10):
+    """
+    Bins data that falls between certain limits, if the limits are (0, 0) the
+    minimum and maximum values are used.
+
+    Returns a list of tuples where the first element of the tuple is the
+    center of the bin and the second element of the tuple are the counts.
+    """
+    if limits == (0, 0):
+        min_val, max_val = min(values) - _EPS, max(values) + _EPS
+    else:
+        min_val, max_val = limits
+
+    # get bin size
+    bin_size = (max_val - min_val) / float(bin_num)
+    bins = [0] * (bin_num)
+
+    # will ignore these outliers for now
+    for value in values:
+        try:
+            if (value - min_val) >= 0:
+                index = int((value - min_val) / float(bin_size))
+                bins[index] += 1
+        except IndexError:
+            pass
+
+    # make it ready for an x,y plot
+    result = []
+    center = (bin_size / 2) + min_val
+    for i, y in enumerate(bins):
+        x = center + bin_size * i
+        result.append((x, y))
+
+    return result