Python numpy.fft.fftfreq() Examples
The following are 29 code examples for showing how to use numpy.fft.fftfreq(). These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example.
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Example 1
Project: diffsims Author: pyxem File: fourier_transform.py License: GNU General Public License v3.0 | 7 votes |
def from_recip(y): """ Converts Fourier frequencies to spatial coordinates. Parameters ---------- y : `list` [`numpy.ndarray` [`float`]], of shape [(nx,), (ny,), ...] List (or equivalent) of vectors which define a mesh in the dimension equal to the length of `x` Returns ------- x : `list` [`numpy.ndarray` [`float`]], of shape [(nx,), (ny,), ...] List of vectors defining a mesh such that for a function, `f`, defined on the mesh given by `y`, ifft(f) is defined on the mesh given by `x`. 0 will be in the middle of `x`. """ x = [] for Y in y: if Y.size > 1: x.append(fftfreq(Y.size, Y.item(1) - Y.item(0)) * (2 * pi)) else: x.append(array([0])) x[-1] = x[-1].astype(Y.dtype, copy=False) return [fftshift(X) for X in x]
Example 2
Project: diffsims Author: pyxem File: fourier_transform.py License: GNU General Public License v3.0 | 6 votes |
def to_recip(x): """ Converts spatial coordinates to Fourier frequencies. Parameters ---------- x : `list` [`numpy.ndarray` [`float`]], of shape [(nx,), (ny,), ...] List (or equivalent) of vectors which define a mesh in the dimension equal to the length of `x` Returns ------- y : `list` [`numpy.ndarray` [`float`]], of shape [(nx,), (ny,), ...] List of vectors defining a mesh such that for a function, `f`, defined on the mesh given by `x`, `fft(f)` is defined on the mesh given by `y` """ y = [] for X in x: if X.size > 1: y.append(fftfreq(X.size, X.item(1) - X.item(0)) * (2 * pi)) else: y.append(array([0])) y[-1] = y[-1].astype(X.dtype, copy=False) return [fftshift(Y) for Y in y]
Example 3
Project: pysteps Author: pySTEPS File: fft.py License: BSD 3-Clause "New" or "Revised" License | 6 votes |
def get_numpy(shape, fftn_shape=None, **kwargs): import numpy.fft as numpy_fft f = { "fft2": numpy_fft.fft2, "ifft2": numpy_fft.ifft2, "rfft2": numpy_fft.rfft2, "irfft2": lambda X: numpy_fft.irfft2(X, s=shape), "fftshift": numpy_fft.fftshift, "ifftshift": numpy_fft.ifftshift, "fftfreq": numpy_fft.fftfreq, } if fftn_shape is not None: f["fftn"] = numpy_fft.fftn fft = SimpleNamespace(**f) return fft
Example 4
Project: pysteps Author: pySTEPS File: fft.py License: BSD 3-Clause "New" or "Revised" License | 6 votes |
def get_scipy(shape, fftn_shape=None, **kwargs): import numpy.fft as numpy_fft import scipy.fftpack as scipy_fft # use numpy implementation of rfft2/irfft2 because they have not been # implemented in scipy.fftpack f = { "fft2": scipy_fft.fft2, "ifft2": scipy_fft.ifft2, "rfft2": numpy_fft.rfft2, "irfft2": lambda X: numpy_fft.irfft2(X, s=shape), "fftshift": scipy_fft.fftshift, "ifftshift": scipy_fft.ifftshift, "fftfreq": scipy_fft.fftfreq, } if fftn_shape is not None: f["fftn"] = scipy_fft.fftn fft = SimpleNamespace(**f) return fft
Example 5
Project: recruit Author: Frank-qlu File: test_helper.py License: Apache License 2.0 | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 6
Project: lambda-packs Author: ryfeus File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 7
Project: auto-alt-text-lambda-api Author: abhisuri97 File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 8
Project: vnpy_crypto Author: birforce File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 9
Project: vnpy_crypto Author: birforce File: fftarma.py License: MIT License | 5 votes |
def spd(self, npos): '''raw spectral density, returns Fourier transform n is number of points in positive spectrum, the actual number of points is twice as large. different from other spd methods with fft ''' n = npos w = fft.fftfreq(2*n) * 2 * np.pi hw = self.fftarma(2*n) #not sure, need to check normalization #return (hw*hw.conj()).real[n//2-1:] * 0.5 / np.pi #doesn't show in plot return (hw*hw.conj()).real * 0.5 / np.pi, w
Example 10
Project: vnpy_crypto Author: birforce File: fftarma.py License: MIT License | 5 votes |
def spdshift(self, n): '''power spectral density using fftshift currently returns two-sided according to fft frequencies, use first half ''' #size = s1+s2-1 mapadded = self.padarr(self.ma, n) arpadded = self.padarr(self.ar, n) hw = fft.fft(fft.fftshift(mapadded)) / fft.fft(fft.fftshift(arpadded)) #return np.abs(spd)[n//2-1:] w = fft.fftfreq(n) * 2 * np.pi wslice = slice(n//2-1, None, None) #return (hw*hw.conj()).real[wslice], w[wslice] return (hw*hw.conj()).real, w
Example 11
Project: vnpy_crypto Author: birforce File: fftarma.py License: MIT License | 5 votes |
def spddirect(self, n): '''power spectral density using padding to length n done by fft currently returns two-sided according to fft frequencies, use first half ''' #size = s1+s2-1 #abs looks wrong hw = fft.fft(self.ma, n) / fft.fft(self.ar, n) w = fft.fftfreq(n) * 2 * np.pi wslice = slice(None, n//2, None) #return (np.abs(hw)**2)[wslice], w[wslice] return (np.abs(hw)**2) * 0.5/np.pi, w
Example 12
Project: Computable Author: ktraunmueller File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 13
Project: Mastering-Elasticsearch-7.0 Author: PacktPublishing File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 14
Project: GraphicDesignPatternByPython Author: Relph1119 File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 15
Project: predictive-maintenance-using-machine-learning Author: awslabs File: test_helper.py License: Apache License 2.0 | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 16
Project: pySINDy Author: luckystarufo File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 17
Project: mxnet-lambda Author: awslabs File: test_helper.py License: Apache License 2.0 | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 18
Project: ImageFusion Author: pfchai File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 19
Project: Splunking-Crime Author: nccgroup File: fftarma.py License: GNU Affero General Public License v3.0 | 5 votes |
def spd(self, npos): '''raw spectral density, returns Fourier transform n is number of points in positive spectrum, the actual number of points is twice as large. different from other spd methods with fft ''' n = npos w = fft.fftfreq(2*n) * 2 * np.pi hw = self.fftarma(2*n) #not sure, need to check normalization #return (hw*hw.conj()).real[n//2-1:] * 0.5 / np.pi #doesn't show in plot return (hw*hw.conj()).real * 0.5 / np.pi, w
Example 20
Project: Splunking-Crime Author: nccgroup File: fftarma.py License: GNU Affero General Public License v3.0 | 5 votes |
def spdshift(self, n): '''power spectral density using fftshift currently returns two-sided according to fft frequencies, use first half ''' #size = s1+s2-1 mapadded = self.padarr(self.ma, n) arpadded = self.padarr(self.ar, n) hw = fft.fft(fft.fftshift(mapadded)) / fft.fft(fft.fftshift(arpadded)) #return np.abs(spd)[n//2-1:] w = fft.fftfreq(n) * 2 * np.pi wslice = slice(n//2-1, None, None) #return (hw*hw.conj()).real[wslice], w[wslice] return (hw*hw.conj()).real, w
Example 21
Project: Splunking-Crime Author: nccgroup File: fftarma.py License: GNU Affero General Public License v3.0 | 5 votes |
def spddirect(self, n): '''power spectral density using padding to length n done by fft currently returns two-sided according to fft frequencies, use first half ''' #size = s1+s2-1 #abs looks wrong hw = fft.fft(self.ma, n) / fft.fft(self.ar, n) w = fft.fftfreq(n) * 2 * np.pi wslice = slice(None, n//2, None) #return (np.abs(hw)**2)[wslice], w[wslice] return (np.abs(hw)**2) * 0.5/np.pi, w
Example 22
Project: spectral_connectivity Author: Eden-Kramer-Lab File: transforms.py License: GNU General Public License v3.0 | 5 votes |
def frequencies(self): return fftfreq(self.n_fft_samples, 1.0 / self.sampling_frequency)
Example 23
Project: pyem Author: asarnow File: sort.py License: GNU General Public License v3.0 | 5 votes |
def main(args): pyfftw.interfaces.cache.enable() refmap = mrc.read(args.key, compat="relion") df = star.parse_star(args.input, keep_index=False) star.augment_star_ucsf(df) refmap_ft = vop.vol_ft(refmap, threads=args.threads) apix = star.calculate_apix(df) sz = refmap_ft.shape[0] // 2 - 1 sx, sy = np.meshgrid(rfftfreq(sz), fftfreq(sz)) s = np.sqrt(sx ** 2 + sy ** 2) r = s * sz r = np.round(r).astype(np.int64) r[r > sz // 2] = sz // 2 + 1 a = np.arctan2(sy, sx) def1 = df["rlnDefocusU"].values def2 = df["rlnDefocusV"].values angast = df["rlnDefocusAngle"].values phase = df["rlnPhaseShift"].values kv = df["rlnVoltage"].values ac = df["rlnAmplitudeContrast"].values cs = df["rlnSphericalAberration"].values xshift = df["rlnOriginX"].values yshift = df["rlnOriginY"].values score = np.zeros(df.shape[0]) # TODO parallelize for i, row in df.iterrows(): xcor = particle_xcorr(row, refmap_ft) if args.top is None: args.top = df.shape[0] top = df.iloc[np.argsort(score)][:args.top] star.simplify_star_ucsf(top) star.write_star(args.output, top) return 0
Example 24
Project: elasticintel Author: securityclippy File: test_helper.py License: GNU General Public License v3.0 | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 25
Project: coffeegrindsize Author: jgagneastro File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 26
Project: Serverless-Deep-Learning-with-TensorFlow-and-AWS-Lambda Author: PacktPublishing File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 27
Project: twitter-stock-recommendation Author: alvarobartt File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 28
Project: keras-lambda Author: sunilmallya File: test_helper.py License: MIT License | 5 votes |
def test_definition(self): x = [0, 1, 2, 3, 4, -4, -3, -2, -1] assert_array_almost_equal(9*fft.fftfreq(9), x) assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] assert_array_almost_equal(10*fft.fftfreq(10), x) assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x)
Example 29
Project: nltools Author: cosanlab File: plotting.py License: MIT License | 4 votes |
def component_viewer(output, tr=2.0): ''' This a function to interactively view the results of a decomposition analysis Args: output: (dict) output dictionary from running Brain_data.decompose() tr: (float) repetition time of data ''' if ipywidgets is None: raise ImportError( "ipywidgets is required for interactive plotting. Please install this package manually or install nltools with optional arguments: pip install 'nltools[interactive_plots]'" ) def component_inspector(component, threshold): '''This a function to be used with ipywidgets to interactively view a decomposition analysis Make sure you have tr and output assigned to variables. Example: from ipywidgets import BoundedFloatText, BoundedIntText from ipywidgets import interact tr = 2.4 output = data_filtered_smoothed.decompose(algorithm='ica', n_components=30, axis='images', whiten=True) interact(component_inspector, component=BoundedIntText(description='Component', value=0, min=0, max=len(output['components'])-1), threshold=BoundedFloatText(description='Threshold', value=2.0, min=0, max=4, step=.1)) ''' _, ax = plt.subplots(nrows=3, figsize=(12,8)) thresholded = (output['components'][component] - output['components'][component].mean())*(1/output['components'][component].std()) thresholded.data[np.abs(thresholded.data) <= threshold] = 0 plot_stat_map(thresholded.to_nifti(), cut_coords=range(-40, 70, 10), display_mode='z', black_bg=True, colorbar=True, annotate=False, draw_cross=False, axes=ax[0]) if isinstance(output['decomposition_object'], (sklearn.decomposition.PCA)): var_exp = output['decomposition_object'].explained_variance_ratio_[component] ax[0].set_title(f"Component: {component}/{len(output['components'])}, Variance Explained: {var_exp:2.2}", fontsize=18) else: ax[0].set_title(f"Component: {component}/{len(output['components'])}", fontsize=18) ax[1].plot(output['weights'][:, component], linewidth=2, color='red') ax[1].set_ylabel('Intensity (AU)', fontsize=18) ax[1].set_title(f'Timecourse (TR={tr})', fontsize=16) y = fft(output['weights'][:, component]) f = fftfreq(len(y), d=tr) ax[2].plot(f[f > 0], np.abs(y)[f > 0]**2) ax[2].set_ylabel('Power', fontsize=18) ax[2].set_xlabel('Frequency (Hz)', fontsize=16) ipywidgets.interact(component_inspector, component=ipywidgets.BoundedIntText(description='Component', value=0, min=0, max=len(output['components'])-1), threshold=ipywidgets.BoundedFloatText(description='Threshold', value=2.0, min=0, max=4, step=.1))