Python numpy.real方法代码示例

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def quadrature_cc_1D(N):
    """ Computes the Clenshaw Curtis nodes and weights """
    N = np.int(N)        
    if N == 1:
        knots = 0
        weights = 2
    else:
        n = N - 1
        C = np.zeros((N,2))
        k = 2*(1+np.arange(np.floor(n/2)))
        C[::2,0] = 2/np.hstack((1, 1-k*k))
        C[1,1] = -n
        V = np.vstack((C,np.flipud(C[1:n,:])))
        F = np.real(ifft(V, n=None, axis=0))
        knots = F[0:N,1]
        weights = np.hstack((F[0,0],2*F[1:n,0],F[n,0]))
            
    return knots, weights 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def test_dft_real_2d(self):
        """
        Test the real discrete Fourier transform function on one-dimensional
        data. Non-trivial because we need to keep only some of the negative
        frequencies.
        """
        Nx, Ny = 16, 32
        da = xr.DataArray(np.random.rand(Nx, Ny), dims=['x', 'y'],
                          coords={'x': range(Nx), 'y': range(Ny)})
        dx = float(da.x[1] - da.x[0])
        dy = float(da.y[1] - da.y[0])

        daft = xrft.dft(da, real='x')
        npt.assert_almost_equal(daft.values,
                               np.fft.rfftn(da.transpose('y','x')).transpose())
        npt.assert_almost_equal(daft.values,
                               xrft.dft(da, dim=['y'], real='x'))

        actual_freq_x = daft.coords['freq_x'].values
        expected_freq_x = np.fft.rfftfreq(Nx, dx)
        npt.assert_almost_equal(actual_freq_x, expected_freq_x)

        actual_freq_y = daft.coords['freq_y'].values
        expected_freq_y = np.fft.fftfreq(Ny, dy)
        npt.assert_almost_equal(actual_freq_y, expected_freq_y) 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def classical_mds(self, D):
        ''' 
        Classical multidimensional scaling

        Parameters
        ----------
        D : square 2D ndarray
            Euclidean Distance Matrix (matrix containing squared distances between points
        '''

        # Apply MDS algorithm for denoising
        n = D.shape[0]
        J = np.eye(n) - np.ones((n,n))/float(n)
        G = -0.5*np.dot(J, np.dot(D, J))

        s, U = np.linalg.eig(G)

        # we need to sort the eigenvalues in decreasing order
        s = np.real(s)
        o = np.argsort(s)
        s = s[o[::-1]]
        U = U[:,o[::-1]]

        S = np.diag(s)[0:self.dim,:]
        self.X = np.dot(np.sqrt(S),U.T) 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def get_cosine_dist(A, B):
    B = np.reshape(B, (1, -1))
    
    if A.shape[1] == 1:
        A = np.hstack((A, np.zeros((A.shape[0], 1))))
        B = np.hstack((B, np.zeros((B.shape[0], 1))))
    
    aa = np.sum(np.multiply(A, A), axis=1).reshape(-1, 1)
    bb = np.sum(np.multiply(B, B), axis=1).reshape(-1, 1)
    ab = A @ B.T
    
    # to avoid NaN for zero norm
    aa[aa==0] = 1
    bb[bb==0] = 1
    
    D = np.real(np.ones((A.shape[0], B.shape[0])) - np.multiply((1/np.sqrt(np.kron(aa, bb.T))), ab))
    
    return D 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def fft_convolve(*images):
    """Use FFT's to convove an image with a kernel

    Parameters
    ----------
    images: list of array-like
        A list of images to convolve.

    Returns
    -------
    result: array
        The convolution in pixel space of `img` with `kernel`.
    """
    from autograd.numpy.numpy_boxes import ArrayBox

    Images = [np.fft.fft2(np.fft.ifftshift(img)) for img in images]
    if np.any([isinstance(img, ArrayBox) for img in images]):
        Convolved = Images[0]
        for img in Images[1:]:
            Convolved = Convolved * img
    else:
        Convolved = np.prod(Images, 0)
    convolved = np.fft.ifft2(Convolved)
    return np.fft.fftshift(np.real(convolved)) 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def diagonalize_asymm(H):
    """
    Diagonalize a real, *asymmetric* matrix and return sorted results.

    Return the eigenvalues and eigenvectors (column matrix)
    sorted from lowest to highest eigenvalue.
    """
    E,C = np.linalg.eig(H)
    #if np.allclose(E.imag, 0*E.imag):
    #    E = np.real(E)
    #else:
    #    print "WARNING: Eigenvalues are complex, will be returned as such."

    idx = E.real.argsort()
    E = E[idx]
    C = C[:,idx]

    return E,C 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def __init__(self,matr_multiply,xStart,inPreCon,nroots=1,tol=1e-10):
        self.matrMultiply = matr_multiply
        self.size = xStart.shape[0]
        self.nEigen = min(nroots, self.size)
        self.maxM = min(30, self.size)
        self.maxOuterLoop = 10
        self.tol = tol

        #
        #  Creating initial guess and preconditioner
        #
        self.x0 = xStart.real.copy()

        self.iteration = 0
        self.totalIter = 0
        self.converged = False
        self.preCon = inPreCon.copy()
        #
        #  Allocating other vectors
        #
        self.allocateVecs() 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def solveSubspace(self):
        w, v = scipy.linalg.eig(self.subH[:self.currentSize,:self.currentSize])
        idx = w.real.argsort()
        v = v[:,idx]
        w = w[idx].real
#
        imag_norm = np.linalg.norm(w.imag)
        if imag_norm > 1e-12:
            print(" *************************************************** ")
            print(" WARNING  IMAGINARY EIGENVALUE OF NORM %.15g " % (imag_norm))
            print(" *************************************************** ")
        #print "Imaginary norm eigenvectors = ", np.linalg.norm(v.imag)
        #print "Imaginary norm eigenvalue   = ", np.linalg.norm(w.imag)
        #print "eigenvalues = ", w[:min(self.currentSize,7)]
#
        self.sol[:self.currentSize] = v[:,self.ciEig]
        self.evecs[:self.currentSize,:self.currentSize] = v
        self.eigs[:self.currentSize] = w[:self.currentSize]
        self.outeigs[:self.nEigen] = w[:self.nEigen]
        self.cvEig = self.eigs[self.ciEig] 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def energy(self, configs):
        r"""
        Compute Coulomb energy for a set of configs.  

        .. math:: E_{\rm Coulomb} &= E_{\rm real+reciprocal}^{ee} 
                + E_{\rm self+charged}^{ee} 
                \\&+ E_{\rm real+reciprocal}^{e\text{-ion}} 
                + E_{\rm self+charged}^{e\text{-ion}} 
                \\&+ E_{\rm real+reciprocal}^{\text{ion-ion}} 
                + E_{\rm self+charged}^{\text{ion-ion}}
        
        Inputs:
            configs: pyqmc PeriodicConfigs object of shape (nconf, nelec, ndim)
        Returns: 
            ee: electron-electron part
            ei: electron-ion part
            ii: ion-ion part
        """
        nelec = configs.configs.shape[1]
        ee, ei = self.ewald_electron(configs)
        ee += self.ee_const(nelec)
        ei += self.ei_const(nelec)
        ii = self.ion_ion + self.ii_const
        return ee, ei, ii 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def damp(self):
        '''Natural frequency, damping ratio of system poles

        Returns
        -------
        wn : array
            Natural frequencies for each system pole
        zeta : array
            Damping ratio for each system pole
        poles : array
            Array of system poles
        '''
        poles = self.pole()

        if isdtime(self, strict=True):
            splane_poles = np.log(poles)/self.dt
        else:
            splane_poles = poles
        wn = absolute(splane_poles)
        Z = -real(splane_poles)/wn
        return wn, Z, poles 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def _break_points(num, den):
    """Extract break points over real axis and gains given these locations"""
    # type: (np.poly1d, np.poly1d) -> (np.array, np.array)
    dnum = num.deriv(m=1)
    dden = den.deriv(m=1)
    polynom = den * dnum - num * dden
    real_break_pts = polynom.r
    # don't care about infinite break points
    real_break_pts = real_break_pts[num(real_break_pts) != 0]
    k_break = -den(real_break_pts) / num(real_break_pts)
    idx = k_break >= 0   # only positives gains
    k_break = k_break[idx]
    real_break_pts = real_break_pts[idx]
    if len(k_break) == 0:
        k_break = [0]
        real_break_pts = den.roots
    return k_break, real_break_pts 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def control_output(t, x, u, params):
    # Get the controller parameters
    longpole = params.get('longpole', -2.)
    latpole1 = params.get('latpole1', -1/2 + sqrt(-7)/2)
    latpole2 = params.get('latpole2', -1/2 - sqrt(-7)/2)
    l = params.get('wheelbase', 3)
    
    # Extract the system inputs
    ex, ey, etheta, vd, phid = u

    # Determine the controller gains
    alpha1 = -np.real(latpole1 + latpole2)
    alpha2 = np.real(latpole1 * latpole2)

    # Compute and return the control law
    v = -longpole * ex          # Note: no feedfwd (to make plot interesting)
    if vd != 0:
        phi = phid + (alpha1 * l) / vd * ey + (alpha2 * l) / vd * etheta
    else:
        # We aren't moving, so don't turn the steering wheel
        phi = phid
    
    return  np.array([v, phi])

# Define the controller as an input/output system 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def compact(self, complex_coeff_tape=True):
        """
        Generate a compact form of this polynomial designed for fast evaluation.

        The resulting "tapes" can be evaluated using
        :function:`opcalc.bulk_eval_compact_polys`.

        Parameters
        ----------
        complex_coeff_tape : bool, optional
            Whether the `ctape` returned array is forced to be of complex type.
            If False, the real part of all coefficients is taken (even if they're
            complex).

        Returns
        -------
        vtape, ctape : numpy.ndarray
            These two 1D arrays specify an efficient means for evaluating this
            polynomial.
        """
        if complex_coeff_tape:
            return self._rep.compact_complex()
        else:
            return self._rep.compact_real() 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def safe_bulk_eval_compact_polys(vtape, ctape, paramvec, dest_shape):
    """Typechecking wrapper for :function:`bulk_eval_compact_polys`.

    The underlying method has two implementations: one for real-valued
    `ctape`, and one for complex-valued. This wrapper will dynamically
    dispatch to the appropriate implementation method based on the
    type of `ctape`. If the type of `ctape` is known prior to calling,
    it's slightly faster to call the appropriate implementation method
    directly; if not.
    """
    if _np.iscomplexobj(ctape):
        ret = bulk_eval_compact_polys_complex(vtape, ctape, paramvec, dest_shape)
        im_norm = _np.linalg.norm(_np.imag(ret))
        if im_norm > 1e-6:
            print("WARNING: norm(Im part) = {:g}".format(im_norm))
    else:
        ret = bulk_eval_compact_polys(vtape, ctape, paramvec, dest_shape)
    return _np.real(ret) 

# 需要导入模块: import numpy [as 别名]
# 或者: from numpy import real [as 别名]
def absdiff(self, constant_value, separate_re_im=False):
        """
        Returns a ReportableQty that is the (element-wise in the vector case)
        difference between `constant_value` and this one given by:

        `abs(self - constant_value)`.
        """
        if separate_re_im:
            re_v = _np.fabs(_np.real(self.value) - _np.real(constant_value))
            im_v = _np.fabs(_np.imag(self.value) - _np.imag(constant_value))
            if self.has_eb():
                return (ReportableQty(re_v, _np.fabs(_np.real(self.errbar)), self.nonMarkovianEBs),
                        ReportableQty(im_v, _np.fabs(_np.imag(self.errbar)), self.nonMarkovianEBs))
            else:
                return ReportableQty(re_v), ReportableQty(im_v)

        else:
            v = _np.absolute(self.value - constant_value)
            if self.has_eb():
                return ReportableQty(v, _np.absolute(self.errbar), self.nonMarkovianEBs)
            else:
                return ReportableQty(v)