test_filter.py 文件源码

def test_percentile_nasty_partitions(self):
        # Test percentile with nasty partitions: divide up 5 assets into
        # quartiles.
        # There isn't a nice mathematical definition of correct behavior here,
        # so for now we guarantee the behavior of numpy.nanpercentile.  This is
        # mostly for regression testing in case we write our own specialized
        # percentile calculation at some point in the future.

        data = arange(25, dtype=float).reshape(5, 5) % 4
        quartiles = range(4)
        filter_names = ['pct_' + str(q) for q in quartiles]

        graph = TermGraph(
            {
                name: self.f.percentile_between(q * 25.0, (q + 1) * 25.0)
                for name, q in zip(filter_names, quartiles)
            }
        )
        results = self.run_graph(
            graph,
            initial_workspace={self.f: data},
            mask=self.build_mask(ones((5, 5))),
        )

        for name, quartile in zip(filter_names, quartiles):
            result = results[name]
            lower = quartile * 25.0
            upper = (quartile + 1) * 25.0
            expected = and_(
                nanpercentile(data, lower, axis=1, keepdims=True) <= data,
                data <= nanpercentile(data, upper, axis=1, keepdims=True),
            )
            check_arrays(result, expected)