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44 lines
1.0 KiB
44 lines
1.0 KiB
# $Id: __init__.py,v 1.3 2010-09-10 21:23:59 wirawan Exp $
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#
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# wpylib.math main module
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# Created: 20091204
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# Wirawan Purwanto
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#
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pass
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import numpy
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ZERO_TOL = 5.0e-16
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def ztol(val, tol=None, copy=True):
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"""Rounds down values to zero if they are below tolerance."""
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if tol == None: tol = ZERO_TOL
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if "__iter__" not in dir(val):
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if numpy.abs(val) < tol:
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return 0
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else:
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return val
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elif isinstance(val, numpy.ndarray):
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if copy:
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rslt = val.copy()
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else:
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rslt = val
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numpy.putmask(rslt, numpy.abs(rslt) < tol, [0])
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return rslt
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else:
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raise ValueError, "Unsupported datatype: %s" % str(type(val))
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def epsilon(dtype):
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"""A simple way to determine (at runtime) the precision of a given type
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real number.
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Precision is defined such that (1.0 + epsilon(dtype) > 1.0).
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Below this number, the addition will not yield a different result.
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"""
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one = dtype(1.0)
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small = one
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small2 = small
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while one + small > one:
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small2 = small
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small = dtype(small / 2)
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return small2
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