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