Python scipy.diff函数代码示例

 def diff(self, n=1):
     """Calculate the n-th order differential of the function."""
     # 2012-06-27 - 2012-07-11
     x, y = self.diff(n=n-1).xy() if n > 1 else self.xy()
     x = self._filter_double(x)
     return type(self)(x=.5*(x[1:]+x[:-1]),
                       y=scipy.diff(y)/scipy.diff(x))

def gradient2(f):
	dM = g.grid_M[1] - g.grid_M[0]
	dD = g.grid_D[1] - g.grid_D[0]	
	g1 = scipy.diff(f, 1, 0) / dM
	g2 = scipy.diff(f, 1, 1) / dD
	g3 = addNanRow(g1)
	g4 = addNanCol(g2)
	return [g3, g4]

def entropy2(values):
    """Calculate the entropy of vector values.
    
    values will be flattened to a 1d ndarray."""
    
    values = sp.asarray(values).flatten()
    p = sp.diff(sp.c_[0,sp.diff(sp.sort(values)).nonzero(), values.size])/float(values.size)
    H = (p*sp.log2(p)).sum()
    return -H

def entropy2(values):
    """Calculate the entropy of vector values.
    
    values will be flattened to a 1d ndarray."""
    
    values = values.flatten()
    M = len(sp.unique(values))
    p = sp.diff(sp.c_[sp.diff(sp.sort(values)).nonzero(), len(values)])/float(len(values))
    H = -((p*sp.log2(p)).sum())
    return H

 def test_respects_refractory_period(self):
     refractory = 100 * pq.ms
     st = self.invoke_gen_func(
         self.highRate, max_spikes=1000, refractory=refractory)
     self.assertGreater(
         sp.amax(sp.absolute(sp.diff(st.rescale(pq.s).magnitude))),
         refractory.rescale(pq.s).magnitude)
     st = self.invoke_gen_func(
         self.highRate, t_stop=10 * pq.s, refractory=refractory)
     self.assertGreater(
         sp.amax(sp.absolute(sp.diff(st.rescale(pq.s).magnitude))),
         refractory.rescale(pq.s).magnitude)

    def qrs_detect(self, qrslead=0):
         """Detect QRS onsets using modified PT algorithm
         """
         # If ecg is a vector, it will be used for qrs detection.
         # If it is a matrix, use qrslead (default 0)
         if len(self.data.shape) == 1:
             self.raw_ecg = self.data
         else:
             self.raw_ecg = self.data[:,qrslead]

         # butterworth bandpass filter 5 - 15 Hz
         self.filtered_ecg = self._bpfilter(self.raw_ecg)
         # differentiate
         self.diff_ecg  = scipy.diff(self.filtered_ecg)
         # take absolute value (was square in original PT implementation)
         self.abs_ecg = abs(self.diff_ecg)
         # integrate 
         self.int_ecg = self._mw_integrate(self.abs_ecg)
         
         # Construct buffers with last 8 values 
         self._initializeBuffers(self.int_ecg)

         # collect all unique local peaks in the integrated ecg
         peaks = self.peakDetect(self.int_ecg)

         # classify each peak as QRS or noise
         self.checkPeaks(peaks, self.int_ecg)


         # compensate for delay during integration
         self.QRSpeaks -= 40 * (self.samplingrate / 1000)
         
         return self.QRSpeaks

def detect_signals():
    vector, label = weeklydataset_sg_ndata(
        "/media/4AC0AB31C0AB21E5/Documents and Settings/Claudio/Documenti/Thesis/Workloads/MSClaudio/ews/access_log-20110805.csv",
        [],
    )
    x, target = aggregatebymins_sg_ndata(vector[1])

    starttime = time.time()
    y = array(target)
    t = array(x)
    thr = max(y) * 2 / 3
    print thr
    I = pylab.find(y > thr)
    #    print I
    #    pylab.plot(t,y, 'b',label='signal')
    #    pylab.plot(t[I], y[I],'ro',label='detections')
    #    pylab.plot([0, t[len(t)-1]], [thr,thr], 'g--')

    J = pylab.find(diff(I) > 1)
    argpeak = []
    targetpeak = []
    for K in split(I, J + 1):
        ytag = y[K]
        peak = pylab.find(ytag == max(ytag))
        #        pylab.plot(peak+K[0],ytag[peak],'sg',ms=7)
        argpeak.append(peak + K[0])
        targetpeak.append(ytag[peak])

    eta = time.time() - starttime
    print "time elapsed %f" % eta
    return list(itertools.chain(*argpeak)), list(itertools.chain(*targetpeak))

 def execute(self):
     self.power_mat, self.thermal_expectation = self.full_calculation()
     n_chan = self.power_mat.shape[1]
     n_freq = self.power_mat.shape[0]
     # Calculate the the mean channel correlations at low frequencies.
     low_f_mat = sp.mean(self.power_mat[1:4 * n_chan + 1,:,:], 0).real
     # Factorize it into preinciple components.
     e, v = linalg.eigh(low_f_mat)
     self.low_f_mode_values = e
     # Make sure the eigenvalues are sorted.
     if sp.any(sp.diff(e) < 0):
         raise RuntimeError("Eigenvalues not sorted.")
     self.low_f_modes = v
     # Now subtract out the noisiest channel modes and see what is left.
     n_modes_subtract = 10
     mode_subtracted_power_mat = sp.copy(self.power_mat.real)
     mode_subtracted_auto_power = sp.empty((n_modes_subtract, n_freq))
     for ii in range(n_modes_subtract):
         mode = v[:,-ii]
         amp = sp.sum(mode[:,None] * mode_subtracted_power_mat, 1)
         amp = sp.sum(amp * mode, 1)
         to_subtract = amp[:,None,None] * mode[:,None] * mode
         mode_subtracted_power_mat -= to_subtract
         auto_power = mode_subtracted_power_mat.view()
         auto_power.shape = (n_freq, n_chan**2)
         auto_power = auto_power[:,::n_chan + 1]
         mode_subtracted_auto_power[ii,:] = sp.mean(auto_power, -1)
     self.subtracted_auto_power = mode_subtracted_auto_power

  def scanSound(self, source, minnotel):
    binarized = source
    scale = 60. / self.wavetempo * (binarized[0].size / self.duration)
    noise_length = scale*minnotel

    antinoised = sp.zeros_like(binarized)

    for i in range(sp.shape(binarized)[0]):
      new_line = binarized[i, :].copy()
      diffed = sp.diff(new_line)
      ones_keys = sp.where(diffed == 1)[0]
      minus_keys = sp.where(diffed == -1)[0]
      
      if(ones_keys.size != 0 and minus_keys.size != 0):
        if(ones_keys[0] > minus_keys[0]):
          new_line = self.cutNoise(
              (0, minus_keys[0]), noise_length, new_line)
          minus_keys = sp.delete(minus_keys, 0)

        if(ones_keys[-1] > minus_keys[-1]):
          new_line = self.cutNoise(
              (ones_keys[-1], new_line.size-1), noise_length, new_line)
          ones_keys = sp.delete(ones_keys, -1)

        for j in range(sp.size(ones_keys)):
          new_line = self.cutNoise(
              (ones_keys[j], minus_keys[j]), noise_length, new_line)

        antinoised[i, :] = new_line

    return antinoised

 def get_fft(self, fs, taps, Npts):
     Ts = 1.0/fs
     fftpts = fftpack.fft(taps, Npts)
     self.freq = scipy.arange(0, fs, 1.0/(Npts*Ts))        
     self.fftdB = 20.0*scipy.log10(abs(fftpts))
     self.fftDeg = scipy.unwrap(scipy.angle(fftpts))
     self.groupDelay = -scipy.diff(self.fftDeg)

def get_indices(arr, vals, disp=False):
    """

    Get the indices of all the elements between vals[0] and vals[1].
    Alternatively also between vals[2] and vals[3] if they are given.

    Input:
        arr  : the array in which to look for the elements
        vals : a list with either 2 or 4 values that corresponds
               limits inbetween which the indices of the values

    Optional argument(s):
        disp : Bolean parameter, if True it displays start and end
               index and the number of channels inbetween. Only works
               for value lists of length 2.

    Assumes the values in 'arr' is the mid values and that it is evenly
    spaced for all values.

    ********************** Important! **********************************
    The output indices are Python friendly, i.e. they are 0-based. Take
    when using the indices in other software e.g. GILDAS, MIRIAD, which
    are 1-based.

    --------------------------------------------------------------------

                            oOO Changelog OOo

    *2012/02
        Added more documentation, "important" notice about indexing
    *2011/07
        Removed +1 in the output indices to be compatible with rest of
        module, where Pythons 0-based indexing is used.
    *2010/12
        Doc written
    *2010/06
        Funciton created
    """

    from scipy import concatenate, where, array, diff

    dx = abs(0.5 * diff(arr)[0])
    if len(vals) == 4:
        v1, v2, v3, v4 = vals + array([-1, 1, -1, 1]) * dx
        # if the user wants two velocity areas to calculate noise
        low = where((arr >= v1) * (arr <= v2))[0]
        high = where((arr >= v3) * (arr <= v4))[0]
        channels = concatenate((low, high))
    elif len(vals) == 2:
        v1, v2 = vals + array([-1, 1]) * dx
        # channels = where((arr>=v1)*(arr<v2))[0]+1
        # this is because if +1 it is FITS/Fortran safe
        # changed: removed +1 for consistency in program
        channels = where((arr >= v1) * (arr <= v2))[0]
    #
    if disp and len(vals) == 2:
        first, last = channels.min(), channels.max()
        n = last - first + 1
        print "\nFirst: %d,\n Last: %d\n Nchan: %d\n" % (first, last, n)
    return channels

def decode(file_name):
    border.rotate(file_name)
    image = Image.open("temp.png")
    q = border.find("temp.png")
    ind = sp.argmin(sp.sum(q, 1), 0)
    up_left = q[ind, 0] + 2
    up_top = q[ind, 1] + 2
    d_right = q[ind+1, 0] - 3
    d_bottom = q[ind-1, 1] - 3

    box = (up_left, up_top, d_right, d_bottom)
    region = image.crop(box)
    h_sum = sp.sum(region, 0)
    m = argrelmax(sp.correlate(h_sum, h_sum, 'same'))
    s = sp.average(sp.diff(m))
    m = int(round(d_right - up_left)/s)
    if m % 3 != 0:
        m += 3 - m % 3
    n = int(round(d_bottom - up_top)/s)
    if n % 4 != 0:
        n += 4 - n % 4
    s = int(round(s))+1

    region = region.resize((s*m, s*n), PIL.Image.ANTIALIAS)
    region.save("0.png")
    pix = region.load()
    matrix = mix.off(rec.matrix(pix, s, m, n))
    str2 = hamming.decode(array_to_str(matrix))

    return hamming.bin_to_str(str2)

    def qrsDetect(self, qrslead=0):
         """Detect QRS onsets using modified PT algorithm
         """
         # If ecg is a vector, it will be used for qrs detection.
         # If it is a matrix, use qrslead (default 0)
         if len(self.data.shape) == 1:
             self.raw_ecg = self.data
         else:
             self.raw_ecg = self.data[:,qrslead]
         
         self.filtered_ecg = self.bpfilter(self.raw_ecg)
         self.diff_ecg  = scipy.diff(self.filtered_ecg)
         self.sq_ecg = abs(self.diff_ecg)
         self.int_ecg = self.mw_integrate(self.sq_ecg)
         
         # Construct buffers with last 8 values 
         self._initializeBuffers(self.int_ecg)
         
         peaks = self.peakDetect(self.int_ecg)
         self.checkPeaks(peaks, self.int_ecg)

         # compensate for delay during integration
         self.QRSpeaks = self.QRSpeaks  - 40 * (self.samplingrate / 1000)
         
         #print ("length of qrs peaks and ecg", len(self.QRSpeaks), len(self.raw_ecg))
         #print(self.QRSpeaks)
         return self.QRSpeaks

def continuous_phase(phase, axis=0, center=False):
    """Add and subtract 2 pi such that the phase in the array is
       as continuous as possible, along first or given axis. Optionally,
       it also centers the phase data so that the average is smallest."""

    phase = _n.array(phase, copy=0)

    rowshape = list(phase.shape)
    
    if len(rowshape) > 0:
        rowshape[axis] = 1

        slip = _n.concatenate([ _n.zeros(rowshape),
                                scipy.diff(phase, axis=axis) ],
                              axis=axis)
        slip = _n.around(slip/(2*_n.pi))
        cumslip = scipy.cumsum(slip, axis=axis)

        phase = phase - 2*_n.pi*cumslip
    else:
        pass

    if center:
        offset = _n.around(scipy.average(phase, axis=axis)/(2*_n.pi))
        offset = _n.reshape(offset, rowshape)
        offset = _n.repeat(offset, cumslip.shape[axis], axis=axis)
        phase = phase - 2*_n.pi*offset
    
    return phase

def whittaker(inY,inL=15,inD=2):
    
    """
    cette fonction permet de lisser le signal d'entrée en utilisant le filtre de Whittaker.
    ref: Eilers, P.H.C. (2003) "A perfect smoother", Analytical Chemistry, 75, 3631 – 3636.
    
    Entrée:
    inY: le signal à lisser
    
    inL: correspond au parmètre de lissage. Plus il est grand plus le lissage est élevé. par défaut à 15
    comme dans l'article : 
    Geng, L.; Ma, M.; Wang, X.; Yu, W.; Jia, S.; Wang, H.	Comparison of Eight Techniques 
    for Reconstructing Multi-Satellite Sensor Time-Series NDVI Data Sets in the Heihe River Basin, China. 
    Remote Sens. 2014, 6, 2024-2049.
    
    inD: ordre des differences de pénalités
    
    """
    
    m=sp.size(inY)
    E=sp.eye(m)
    D=sp.diff(E,inD)
    Z=E+ (inL*sp.dot(D,sp.transpose(D)))
    ws=sp.linalg.solve(Z,inY)
    
    return ws