mirror of
https://github.com/wassname/catalyst.git
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Scott Sanderson
107 lines
3.1 KiB
Cython
107 lines
3.1 KiB
Cython
"""
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Template for AdjustedArray windowed iterators.
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This file is intended to be used by inserting it via a Cython include into a
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file that's define a type symbol named `ctype` and string constant named
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`dtype`.
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See Also
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--------
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zipline.lib._floatwindow
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zipline.lib._intwindow
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zipline.lib._datewindow
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"""
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from numpy cimport ndarray
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from numpy import asarray
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ctypedef ctype[:, :] databuffer
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cdef class AdjustedArrayWindow:
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"""
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An iterator representing a moving view over an AdjustedArray.
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Concrete subtypes should subclass this and provide a `data` attribute for
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specific types.
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This object stores a copy of the data from the AdjustedArray over which
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it's iterating. At each step in the iteration, it mutates its copy to
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allow us to show different data when looking back over the array.
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The arrays yielded by this iterator are always views over the underlying
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data.
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"""
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cdef:
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# ctype must be defined by the file into which this is being copied.
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databuffer data
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object viewtype
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readonly Py_ssize_t window_length
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Py_ssize_t anchor, max_anchor, next_adj
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dict adjustments
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list adjustment_indices
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def __cinit__(self,
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databuffer data not None,
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object viewtype not None,
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dict adjustments not None,
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Py_ssize_t offset,
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Py_ssize_t window_length):
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self.data = data
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self.viewtype = viewtype
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self.adjustments = adjustments
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self.adjustment_indices = sorted(adjustments, reverse=True)
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self.window_length = window_length
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self.anchor = window_length + offset
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self.max_anchor = data.shape[0]
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self.next_adj = self.pop_next_adj()
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cdef pop_next_adj(self):
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"""
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Pop the index of the next adjustment to apply from self.adjustment_indices.
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"""
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if len(self.adjustment_indices) > 0:
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return self.adjustment_indices.pop()
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else:
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return self.max_anchor
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def __iter__(self):
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return self
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def __next__(self):
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cdef:
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ndarray out
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object adjustment
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Py_ssize_t start, anchor
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anchor = self.anchor
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if anchor > self.max_anchor:
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raise StopIteration()
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# Apply any adjustments that occured before our current anchor.
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# Equivalently, apply any adjustments known **on or before** the date
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# for which we're calculating a window.
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while self.next_adj < anchor:
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for adjustment in self.adjustments[self.next_adj]:
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adjustment.mutate(self.data)
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self.next_adj = self.pop_next_adj()
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start = anchor - self.window_length
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out = asarray(self.data[start:self.anchor]).view(self.viewtype)
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out.setflags(write=False)
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self.anchor += 1
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return out
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def __repr__(self):
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return "<%s: window_length=%d, anchor=%d, max_anchor=%d, dtype=%r>" % (
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type(self).__name__,
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self.window_length,
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self.anchor,
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self.max_anchor,
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self.viewtype,
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)
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