Thanks to visit codestin.com
Credit goes to github.com

Skip to content

FIX: scaling factor for window with negative value #25122

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 5 commits into from
Feb 7, 2023
Merged

FIX: scaling factor for window with negative value #25122

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
cebd3d7
FIX: scaling factor for window with negative value
gapplef Feb 1, 2023
b2c8f88
Test function for scale factor of flattop window
gapplef Feb 1, 2023
76e53c1
fix bug in `test_psd_window_flattop`
gapplef Feb 1, 2023
456c4cf
update code formatting for `test_psd_window_flattop`
gapplef Feb 2, 2023
0a9e632
code formatting: remove extra blank line
gapplef Feb 7, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 4 additions & 4 deletions lib/matplotlib/mlab.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -395,12 +395,12 @@ def _spectral_helper(x, y=None, NFFT=None, Fs=None, detrend_func=None,
elif mode == 'psd':
result = np.conj(result) * result
elif mode == 'magnitude':
result = np.abs(result) / np.abs(window).sum()
result = np.abs(result) / window.sum()
elif mode == 'angle' or mode == 'phase':
# we unwrap the phase later to handle the onesided vs. twosided case
result = np.angle(result)
elif mode == 'complex':
result /= np.abs(window).sum()
result /= window.sum()

if mode == 'psd':

Expand All @@ -424,10 +424,10 @@ def _spectral_helper(x, y=None, NFFT=None, Fs=None, detrend_func=None,
result /= Fs
# Scale the spectrum by the norm of the window to compensate for
# windowing loss; see Bendat & Piersol Sec 11.5.2.
result /= (np.abs(window)**2).sum()
result /= (window**2).sum()
else:
# In this case, preserve power in the segment, not amplitude
result /= np.abs(window).sum()**2
result /= window.sum()**2

t = np.arange(NFFT/2, len(x) - NFFT/2 + 1, NFFT - noverlap)/Fs

Expand Down
31 changes: 29 additions & 2 deletions lib/matplotlib/tests/test_mlab.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -615,7 +615,7 @@ def test_psd_window_hanning(self):
noverlap=0,
sides=self.sides,
window=mlab.window_none)
spec_c *= len(ycontrol1)/(np.abs(windowVals)**2).sum()
spec_c *= len(ycontrol1)/(windowVals**2).sum()
assert_array_equal(fsp_g, fsp_c)
assert_array_equal(fsp_b, fsp_c)
assert_allclose(spec_g, spec_c, atol=1e-08)
Expand Down Expand Up @@ -662,14 +662,41 @@ def test_psd_window_hanning_detrend_linear(self):
noverlap=0,
sides=self.sides,
window=mlab.window_none)
spec_c *= len(ycontrol1)/(np.abs(windowVals)**2).sum()
spec_c *= len(ycontrol1)/(windowVals**2).sum()
assert_array_equal(fsp_g, fsp_c)
assert_array_equal(fsp_b, fsp_c)
assert_allclose(spec_g, spec_c, atol=1e-08)
# these should not be almost equal
with pytest.raises(AssertionError):
assert_allclose(spec_b, spec_c, atol=1e-08)

def test_psd_window_flattop(self):
# flattop window
# adaption from https://github.com/scipy/scipy/blob\
# /v1.10.0/scipy/signal/windows/_windows.py#L562-L622
a = [0.21557895, 0.41663158, 0.277263158, 0.083578947, 0.006947368]
fac = np.linspace(-np.pi, np.pi, self.NFFT_density_real)
win = np.zeros(self.NFFT_density_real)
for k in range(len(a)):
win += a[k] * np.cos(k * fac)

spec, fsp = mlab.psd(x=self.y,
NFFT=self.NFFT_density,
Fs=self.Fs,
noverlap=0,
sides=self.sides,
window=win,
scale_by_freq=False)
spec_a, fsp_a = mlab.psd(x=self.y,
NFFT=self.NFFT_density,
Fs=self.Fs,
noverlap=0,
sides=self.sides,
window=win)
assert_allclose(spec*win.sum()**2,
spec_a*self.Fs*(win**2).sum(),
atol=1e-08)

def test_psd_windowarray(self):
freqs = self.freqs_density
spec, fsp = mlab.psd(x=self.y,
Expand Down