On 2010-01-25 11:06 AM, Bas wrote:
On 2010-01-25 10:16 AM, Bas wrote:
P.S.
Slightly off-topic rant against both numpy and matlab implementation
of unwrap: They always assume data is in radians. There is some option
to specify the maximum jump size in radians, but to me it would be
more useful to specify the interval of a complete cycle, so that you
can do
unwrapped_radians = unwrap(radians)
unwrapped_degrees = unwrap(degrees, 360)
unwrapped_32bit_counter = unwrap(overflowing_counter, 2**32)
On Jan 25, 5:34 pm, Robert Kern<robert.k...@gmail.com> wrote:>
Rants accompanied with patches are more effective. :-)
As you wish (untested):
def unwrap(p, cycle=2*pi, axis=-1):
"""docstring to be updated"""
p = asarray(p)
half_cycle = cycle / 2
nd = len(p.shape)
dd = diff(p, axis=axis)
slice1 = [slice(None, None)]*nd # full slices
slice1[axis] = slice(1, None)
ddmod = mod(dd+half_cycle, cycle)-half_cycle
_nx.putmask(ddmod, (ddmod==-half_cycle)& (dd> 0), half_cycle)
ph_correct = ddmod - dd;
_nx.putmask(ph_correct, abs(dd)<half_cycle, 0)
up = array(p, copy=True, dtype='d')
up[slice1] = p[slice1] + ph_correct.cumsum(axis)
return up
I never saw a use case for the discontinuity argument, so in my
preferred version it would be removed. Of course this breaks old code
(by who uses this option anyhow??) and breaks compatibility between
matlab and numpy.
Sometimes legitimate features have phase discontinuities greater than pi. If you
want your feature to be accepted, please submit a patch that does not break
backwards compatibility and which updates the docstring and tests appropriately.
I look forward to seeing the complete patch! Thank you.
http://projects.scipy.org/numpy
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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