示例#1
0
 def basis(self, type, M, X_star=None):
     if type is 'monomial':
         if X_star is None:
             Phi = np.zeros((np.shape(self.X)[0], (M + 1)))
             for c in range(0, np.shape(Phi)[1]):
                 Phi[:, c] = self.X[:, 0].T**c
         else:
             Phi = np.zeros((np.shape(X_star)[0], (M + 1)))
             for c in range(0, np.shape(Phi)[1]):
                 Phi[:, c] = X_star[:, 0].T**c
     if type is 'fourier':
         if X_star is None:
             Phi = np.zeros((np.shape(self.X)[0], (M + 1) * 2))
             for c in range(0, np.shape(Phi)[1], 2):
                 Phi[:, c] = np.sin(int(c / 2) * np.pi * self.X[:, 0].T)
                 Phi[:, c + 1] = np.cos(int(c / 2) * np.pi * self.X[:, 0].T)
         else:
             Phi = np.zeros((np.shape(X_star)[0], (M + 1) * 2))
             for c in range(0, np.shape(Phi)[1], 2):
                 Phi[:, c] = np.sin(int(c / 2) * np.pi * X_star[:, 0].T)
                 Phi[:, c + 1] = np.cos(int(c / 2) * np.pi * X_star[:, 0].T)
     if type is 'legendre':
         from numpy.polynomial import Legendre
         if X_star is None:
             Phi = Legendre.basis(M)(self.X)
         else:
             Phi = Legendre.basis(M)(X_star)
     return Phi
示例#2
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def dg_interior_flux_matrix(p):
    """Calculate the interior flux matrix for the standard DG advection equations

    There is an analytical expression I could use for this too.
    See my thesis page 74.
    """
    F = np.zeros((p + 1, p + 1))
    for i in range(0, p + 1):
        dli = L.basis(i).deriv()
        for j in range(0, p + 1):
            lj = L.basis(j)
            F[i, j] = basis.integrate_legendre_product(dli, lj)

    return F
示例#3
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def dg_interior_flux_matrix(p):
    """Calculate the interior flux matrix for the standard DG advection equations

    There is an analytical expression I could use for this too.
    See my thesis page 74.
    """
    F = np.zeros((p + 1, p + 1))
    for i in range(0, p + 1):
        dli = L.basis(i).deriv()
        for j in range(0, p + 1):
            lj = L.basis(j)
            F[i, j] = basis.integrate_legendre_product(dli, lj)

    return F
示例#4
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def icb_interface_flux_matrix(p, K, T):
    """The interface flux matrices for the ICB schemes, we use upwinding
     to get the fluxes.  Denote T the translation necessary to
     evaluate the flux from the other cell.

    """

    # Enhanced polynomial degree
    phat = p + len(K)

    G0 = smp.zeros(p + 1, phat + 1)
    G1 = smp.zeros(p + 1, phat + 1)
    for i in range(0, p + 1):
        for j in range(0, phat + 1):
            li = L.basis(i)
            lj = L.basis(j)
            G0[i, j] = leg.legval(-1, li.coef) * \
                leg.legval(1, lj.coef) * (T**-1)
            G1[i, j] = leg.legval(1, li.coef) * leg.legval(1, lj.coef)

    # Enhancement matrix
    A, Ainv, B, Binv = enhance.enhancement_matrices(p, K)

    # Using the enhanced function in the flux (see notes 21/4/15)
    BL = smp.zeros(phat + 1, phat + 1)
    BR = smp.zeros(phat + 1, phat + 1)
    for i in range(p + 1):
        li = L.basis(i)
        BL[i, i] = 1  # basis.integrate_legendre_product(li,li)
        BR[i, i] = 1  # BL[i,i]
    for i, k in enumerate(K):
        lk = L.basis(k)
        int_lklk = basis.integrate_legendre_product(lk, lk)
        BL[i + p + 1, i + p + 1] = T  # * int_lklk
        BR[i + p + 1, i + p + 1] = (T**(-1))  # * int_lklk

    # reduction matrix
    R = smp.zeros(phat + 1, p + 1)
    for i in range(p + 1):
        R[i, i] = 1
    for i, k in enumerate(K):
        for j in range(p + 1):
            R[i + p + 1, j] = auxf.delta(k, j)

    # Convert to sympy matrices
    G0 = smp.Matrix(G0) * smp.Matrix(Ainv) * BL * R
    G1 = smp.Matrix(G1) * smp.Matrix(Ainv) * BL * R

    return G0, G1
示例#5
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def icb_interface_flux_matrix(p, K, T):
    """The interface flux matrices for the ICB schemes, we use upwinding
     to get the fluxes.  Denote T the translation necessary to
     evaluate the flux from the other cell.

    """

    # Enhanced polynomial degree
    phat = p + len(K)

    G0 = smp.zeros(p + 1, phat + 1)
    G1 = smp.zeros(p + 1, phat + 1)
    for i in range(0, p + 1):
        for j in range(0, phat + 1):
            li = L.basis(i)
            lj = L.basis(j)
            G0[i, j] = leg.legval(-1, li.coef) * \
                leg.legval(1, lj.coef) * (T**-1)
            G1[i, j] = leg.legval(1, li.coef) * leg.legval(1, lj.coef)

    # Enhancement matrix
    A, Ainv, B, Binv = enhance.enhancement_matrices(p, K)

    # Using the enhanced function in the flux (see notes 21/4/15)
    BL = smp.zeros(phat + 1, phat + 1)
    BR = smp.zeros(phat + 1, phat + 1)
    for i in range(p + 1):
        li = L.basis(i)
        BL[i, i] = 1  # basis.integrate_legendre_product(li,li)
        BR[i, i] = 1  # BL[i,i]
    for i, k in enumerate(K):
        lk = L.basis(k)
        int_lklk = basis.integrate_legendre_product(lk, lk)
        BL[i + p + 1, i + p + 1] = T  # * int_lklk
        BR[i + p + 1, i + p + 1] = (T**(-1))  # * int_lklk

    # reduction matrix
    R = smp.zeros(phat + 1, p + 1)
    for i in range(p + 1):
        R[i, i] = 1
    for i, k in enumerate(K):
        for j in range(p + 1):
            R[i + p + 1, j] = auxf.delta(k, j)

    # Convert to sympy matrices
    G0 = smp.Matrix(G0) * smp.Matrix(Ainv) * BL * R
    G1 = smp.Matrix(G1) * smp.Matrix(Ainv) * BL * R

    return G0, G1
示例#6
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def regress_poly(degree, data, remove_mean=True, axis=-1):
    ''' returns data with degree polynomial regressed out.
    Be default it is calculated along the last axis (usu. time).
    If remove_mean is True (default), the data is demeaned (i.e. degree 0).
    If remove_mean is false, the data is not.
    '''
    IFLOG.debug('Performing polynomial regression on data of shape ' +
                str(data.shape))

    datashape = data.shape
    timepoints = datashape[axis]

    # Rearrange all voxel-wise time-series in rows
    data = data.reshape((-1, timepoints))

    # Generate design matrix
    X = np.ones((timepoints, 1))  # quick way to calc degree 0
    for i in range(degree):
        polynomial_func = Legendre.basis(i + 1)
        value_array = np.linspace(-1, 1, timepoints)
        X = np.hstack((X, polynomial_func(value_array)[:, np.newaxis]))

    # Calculate coefficients
    betas = np.linalg.pinv(X).dot(data.T)

    # Estimation
    if remove_mean:
        datahat = X.dot(betas).T
    else:  # disregard the first layer of X, which is degree 0
        datahat = X[:, 1:].dot(betas[1:, ...]).T
    regressed_data = data - datahat

    # Back to original shape
    return regressed_data.reshape(datashape)
示例#7
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文件: confounds.py 项目: NifTK/nipype
def regress_poly(degree, data, remove_mean=True, axis=-1):
    ''' returns data with degree polynomial regressed out.
    Be default it is calculated along the last axis (usu. time).
    If remove_mean is True (default), the data is demeaned (i.e. degree 0).
    If remove_mean is false, the data is not.
    '''
    IFLOG.debug('Performing polynomial regression on data of shape ' + str(data.shape))

    datashape = data.shape
    timepoints = datashape[axis]

    # Rearrange all voxel-wise time-series in rows
    data = data.reshape((-1, timepoints))

    # Generate design matrix
    X = np.ones((timepoints, 1)) # quick way to calc degree 0
    for i in range(degree):
        polynomial_func = Legendre.basis(i + 1)
        value_array = np.linspace(-1, 1, timepoints)
        X = np.hstack((X, polynomial_func(value_array)[:, np.newaxis]))

    # Calculate coefficients
    betas = np.linalg.pinv(X).dot(data.T)

    # Estimation
    if remove_mean:
        datahat = X.dot(betas).T
    else: # disregard the first layer of X, which is degree 0
        datahat = X[:, 1:].dot(betas[1:, ...]).T
    regressed_data = data - datahat

    # Back to original shape
    return regressed_data.reshape(datashape)
示例#8
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文件: basis.py 项目: wo6677/dg1d
    def evaluate_basis_gauss(self):
        """Evaluate the basis at the Gaussian quadrature nodes.

        phi will be used to transform Legendre solution coefficients
        to the solution evaluated at the Gaussian quadrature nodes.

        dphi_w will be used for the interior flux integral

        """
        phi = np.zeros((len(self.x), self.N_s))
        dphi_w = np.zeros((len(self.x), self.N_s))

        for n in range(self.N_s):

            # Get the Legendre polynomial of order n and its gradient
            l = L.basis(n)
            dl = l.deriv()

            # Evaluate the basis at the Gaussian nodes
            phi[:, n] = leg.legval(self.x, l.coef)

            # Evaluate the gradient at the Gaussian nodes and multiply by the
            # weights
            dphi_w[n, :] = leg.legval(self.x, dl.coef) * self.w

        return phi, dphi_w
示例#9
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文件: basis.py 项目: marchdf/dg1d
    def evaluate_basis_gauss(self):
        """Evaluate the basis at the Gaussian quadrature nodes.

        phi will be used to transform Legendre solution coefficients
        to the solution evaluated at the Gaussian quadrature nodes.

        dphi_w will be used for the interior flux integral

        """
        phi = np.zeros((len(self.x), self.N_s))
        dphi_w = np.zeros((len(self.x), self.N_s))

        for n in range(self.N_s):

            # Get the Legendre polynomial of order n and its gradient
            l = L.basis(n)
            dl = l.deriv()

            # Evaluate the basis at the Gaussian nodes
            phi[:, n] = leg.legval(self.x, l.coef)

            # Evaluate the gradient at the Gaussian nodes and multiply by the
            # weights
            dphi_w[n, :] = leg.legval(self.x, dl.coef) * self.w

        return phi, dphi_w
示例#10
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文件: enhance.py 项目: wo6677/dg1d
def enhancement_matrices(solution_order, modes):
    """Returns the enhancement matrices (and their inverse)

    Returns A and inv(A) where A \hat{u} = [uL;some_modes_of(uR)]
            B and inv(B) where B \hat{u} = [uR;some_modes_of(uL)]

    Note: this is slightly different than what I do in
    icb_functions.py (called by advection.py) where the right hand
    side contains the normalization factors (i.e A x = b where b =
    uL_i \int \phi_i \phi_i dx). Here I put \int \phi_i \phi_i dx into
    A and B (denoted norm down in the code below).

    """

    # Enhanced solution order
    order = solution_order + len(modes)

    # Submatrices to build the main matrix later
    a = np.diag(np.ones(solution_order + 1))
    b = np.zeros((solution_order + 1, len(modes)))
    cl = np.zeros((len(modes), order + 1))
    cr = np.zeros((len(modes), order + 1))

    # Loop on the modes we are keeping in the neighboring cell
    # (the right cell)
    for i, mode in enumerate(modes):

        # Loop on the enhancement basis
        for j in range(order + 1):

            # Basis function in the right cell
            l1 = L.basis(mode)

            # Enhanced basis function extending into the right cell (or left
            # cell)
            ll = basis.shift_legendre_polynomial(L.basis(j), 2)
            lr = basis.shift_legendre_polynomial(L.basis(j), -2)

            # Inner product for the left and right enhancements
            norm = basis.integrate_legendre_product(l1, l1)
            cl[i, j] = basis.integrate_legendre_product(l1, ll) / norm
            cr[i, j] = basis.integrate_legendre_product(l1, lr) / norm

    # Put the matrices together
    A = np.vstack((np.hstack((a, b)), cl))
    B = np.vstack((np.hstack((a, b)), cr))
    return A, np.linalg.inv(A), B, np.linalg.inv(B)
示例#11
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文件: enhance.py 项目: marchdf/dg1d
def enhancement_matrices(solution_order, modes):
    """Returns the enhancement matrices (and their inverse)

    Returns A and inv(A) where A \hat{u} = [uL;some_modes_of(uR)]
            B and inv(B) where B \hat{u} = [uR;some_modes_of(uL)]

    Note: this is slightly different than what I do in
    icb_functions.py (called by advection.py) where the right hand
    side contains the normalization factors (i.e A x = b where b =
    uL_i \int \phi_i \phi_i dx). Here I put \int \phi_i \phi_i dx into
    A and B (denoted norm down in the code below).

    """

    # Enhanced solution order
    order = solution_order + len(modes)

    # Submatrices to build the main matrix later
    a = np.diag(np.ones(solution_order + 1))
    b = np.zeros((solution_order + 1, len(modes)))
    cl = np.zeros((len(modes), order + 1))
    cr = np.zeros((len(modes), order + 1))

    # Loop on the modes we are keeping in the neighboring cell
    # (the right cell)
    for i, mode in enumerate(modes):

        # Loop on the enhancement basis
        for j in range(order + 1):

            # Basis function in the right cell
            l1 = L.basis(mode)

            # Enhanced basis function extending into the right cell (or left
            # cell)
            ll = basis.shift_legendre_polynomial(L.basis(j), 2)
            lr = basis.shift_legendre_polynomial(L.basis(j), -2)

            # Inner product for the left and right enhancements
            norm = basis.integrate_legendre_product(l1, l1)
            cl[i, j] = basis.integrate_legendre_product(l1, ll) / norm
            cr[i, j] = basis.integrate_legendre_product(l1, lr) / norm

    # Put the matrices together
    A = np.vstack((np.hstack((a, b)), cl))
    B = np.vstack((np.hstack((a, b)), cr))
    return A, np.linalg.inv(A), B, np.linalg.inv(B)
示例#12
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def dg_interface_flux_matrix(p, T):
    """The interface flux matrices, we use upwinding to get the fluxes
     Denote T the translation necessary to evaluate the flux from the
     other cell.

    There are also analytical expressions for these. See my thesis page 73.

    """

    G0 = smp.zeros(p + 1)
    G1 = smp.zeros(p + 1)
    for i in range(0, p + 1):
        for j in range(0, p + 1):
            li = L.basis(i)
            lj = L.basis(j)
            G0[i, j] = leg.legval(-1, li.coef) * \
                leg.legval(1, lj.coef) * (T**-1)
            G1[i, j] = leg.legval(1, li.coef) * leg.legval(1, lj.coef)

    return G0, G1
示例#13
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def dg_interface_flux_matrix(p, T):
    """The interface flux matrices, we use upwinding to get the fluxes
     Denote T the translation necessary to evaluate the flux from the
     other cell.

    There are also analytical expressions for these. See my thesis page 73.

    """

    G0 = smp.zeros(p + 1)
    G1 = smp.zeros(p + 1)
    for i in range(0, p + 1):
        for j in range(0, p + 1):
            li = L.basis(i)
            lj = L.basis(j)
            G0[i, j] = leg.legval(-1, li.coef) * \
                leg.legval(1, lj.coef) * (T**-1)
            G1[i, j] = leg.legval(1, li.coef) * leg.legval(1, lj.coef)

    return G0, G1
示例#14
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文件: test_basis.py 项目: wo6677/dg1d
    def test_integrate_legendre_product(self):
        """Is the integral of the product of two Legendre polynomials correct
        """

        # Given a Legendre Polynomial: L(x) = 0.5*(3x^2 -1)
        l1 = L.basis(2)

        # Evaluate L(x+2)
        l2 = basis.shift_legendre_polynomial(l1, 2)

        # The integral of l1*l2 over [-1,1] = 0.4
        self.assertAlmostEqual(basis.integrate_legendre_product(l1, l2), 0.4)
示例#15
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    def test_integrate_legendre_product(self):
        """Is the integral of the product of two Legendre polynomials correct
        """

        # Given a Legendre Polynomial: L(x) = 0.5*(3x^2 -1)
        l1 = L.basis(2)

        # Evaluate L(x+2)
        l2 = basis.shift_legendre_polynomial(l1, 2)

        # The integral of l1*l2 over [-1,1] = 0.4
        self.assertAlmostEqual(basis.integrate_legendre_product(l1, l2), 0.4)
示例#16
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    def test_shift_legendre_polynomial(self):
        """Is the shifting of Legendre polynomials correct"""

        # Given a Legendre Polynomial: L(x) = 0.5*(3x^2 -1)
        l = L.basis(2)

        # Evaluate L(x+2)
        ls = basis.shift_legendre_polynomial(l, 2)

        # This should be equal to 5.5 + 6x + 1.5 x^2
        npt.assert_array_almost_equal(ls.convert(
            kind=P).coef, np.array([5.5, 6, 1.5]), decimal=13)
    def genNoise(self,grid,maxNoiseOrder):
        """Noise is a matrix of Legendre polynomials of 0<order<maxNoiseOrder
        Additionally 60Hz sine and cosine waves are added to account for the DC component of EEG
        grid -- Grid to be used for timing information
        maxNoiseOrder--Maximum order of noise to be considered"""

        if self.grid() is not None and self.noiseOrders() is not None:
            logger.info( 'Generating noise matrix')
            legpoly = np.array([Legendre.basis(i)(np.arange(len(grid.times()))) for i in self.noiseOrders()]).T #Polynomials
            sw = np.sin(60 * np.arange(len(grid.times())) * 2 * np.pi / float(grid.fs())) # Sine for AC component
            cw = np.cos(60 * np.arange(len(grid.times())) * 2 * np.pi / float(grid.fs())) # Cosine for AC component
            legpoly = np.column_stack((legpoly, sw, cw))
            return pd.DataFrame(legpoly,index=self.grid().times())
示例#18
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文件: test_basis.py 项目: wo6677/dg1d
    def test_shift_legendre_polynomial(self):
        """Is the shifting of Legendre polynomials correct"""

        # Given a Legendre Polynomial: L(x) = 0.5*(3x^2 -1)
        l = L.basis(2)

        # Evaluate L(x+2)
        ls = basis.shift_legendre_polynomial(l, 2)

        # This should be equal to 5.5 + 6x + 1.5 x^2
        npt.assert_array_almost_equal(ls.convert(kind=P).coef,
                                      np.array([5.5, 6, 1.5]),
                                      decimal=13)
示例#19
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    def genNoise(self, grid, maxNoiseOrder):
        """Noise is a matrix of Legendre polynomials of 0<order<maxNoiseOrder
        Additionally 60Hz sine and cosine waves are added to account for the DC component of EEG
        grid -- Grid to be used for timing information
        maxNoiseOrder--Maximum order of noise to be considered"""

        if self.grid() is not None and self.noiseOrders() is not None:
            logger.info('Generating noise matrix')
            legpoly = np.array([
                Legendre.basis(i)(np.arange(len(grid.times())))
                for i in self.noiseOrders()
            ]).T  #Polynomials
            sw = np.sin(60 * np.arange(len(grid.times())) * 2 * np.pi /
                        float(grid.fs()))  # Sine for AC component
            cw = np.cos(60 * np.arange(len(grid.times())) * 2 * np.pi /
                        float(grid.fs()))  # Cosine for AC component
            legpoly = np.column_stack((legpoly, sw, cw))
            return pd.DataFrame(legpoly, index=self.grid().times())
示例#20
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def regress_poly(degree, data, remove_mean=True, axis=-1):
    """
    Returns data with degree polynomial regressed out.
    :param bool remove_mean: whether or not demean data (i.e. degree 0),
    :param int axis: numpy array axes along which regression is performed
    """
    timepoints = data.shape[0]
    # Generate design matrix
    X = np.ones((timepoints, 1))  # quick way to calc degree 0
    for i in range(degree):
        polynomial_func = Legendre.basis(i + 1)
        value_array = np.linspace(-1, 1, timepoints)
        X = np.hstack((X, polynomial_func(value_array)[:, np.newaxis]))
    non_constant_regressors = X[:, :-1] if X.shape[1] > 1 else np.array([])
    betas = np.linalg.pinv(X).dot(data)
    if remove_mean:
        datahat = X.dot(betas)
    else:  # disregard the first layer of X, which is degree 0
        datahat = X[:, 1:].dot(betas[1:, ...])
    regressed_data = data - datahat
    return regressed_data, non_constant_regressors
示例#21
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def approx_legendre_poly(Moments):
    
    n_moments = Moments.shape[0]-1
    
    exp_coef = (np.zeros((1)))

    # For method description see, for instance: 
    # Chapter 3 of "The Problem of Moments", James Alexander Shohat, Jacob David Tamarkin
    for i in range(n_moments+1):
        p = Legendre.basis(i).convert(window = [0.0,1.0], kind=Polynomial)
       
        q = (2*i+1)*np.sum(Moments[0:(i+1)]*p.coef)
        
        pq = (p.coef*q)
                
        exp_coef = polynomial.polyadd(exp_coef, pq)

            
    expansion = Polynomial(exp_coef)
   
        
    return expansion
示例#22
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def regress_poly(degree, data, remove_mean=True, axis=-1):
    """
    Returns data with degree polynomial regressed out.

    :param bool remove_mean: whether or not demean data (i.e. degree 0),
    :param int axis: numpy array axes along which regression is performed

    """
    IFLOGGER.debug('Performing polynomial regression on data of shape %s',
                   str(data.shape))

    datashape = data.shape
    timepoints = datashape[axis]

    # Rearrange all voxel-wise time-series in rows
    data = data.reshape((-1, timepoints))

    # Generate design matrix
    X = np.ones((timepoints, 1))  # quick way to calc degree 0
    for i in range(degree):
        polynomial_func = Legendre.basis(i + 1)
        value_array = np.linspace(-1, 1, timepoints)
        X = np.hstack((X, polynomial_func(value_array)[:, np.newaxis]))

    non_constant_regressors = X[:, :-1] if X.shape[1] > 1 else np.array([])

    # Calculate coefficients
    betas = np.linalg.pinv(X).dot(data.T)

    # Estimation
    if remove_mean:
        datahat = X.dot(betas).T
    else:  # disregard the first layer of X, which is degree 0
        datahat = X[:, 1:].dot(betas[1:, ...]).T
    regressed_data = data - datahat

    # Back to original shape
    return regressed_data.reshape(datashape), non_constant_regressors
示例#23
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def regress_poly(degree, data, remove_mean=True, axis=-1):
    """
    Returns data with degree polynomial regressed out.

    :param bool remove_mean: whether or not demean data (i.e. degree 0),
    :param int axis: numpy array axes along which regression is performed

    """
    IFLOGGER.debug('Performing polynomial regression on data of shape %s',
                   str(data.shape))

    datashape = data.shape
    timepoints = datashape[axis]

    # Rearrange all voxel-wise time-series in rows
    data = data.reshape((-1, timepoints))

    # Generate design matrix
    X = np.ones((timepoints, 1))  # quick way to calc degree 0
    for i in range(degree):
        polynomial_func = Legendre.basis(i + 1)
        value_array = np.linspace(-1, 1, timepoints)
        X = np.hstack((X, polynomial_func(value_array)[:, np.newaxis]))

    non_constant_regressors = X[:, :-1] if X.shape[1] > 1 else np.array([])

    # Calculate coefficients
    betas = np.linalg.pinv(X).dot(data.T)

    # Estimation
    if remove_mean:
        datahat = X.dot(betas).T
    else:  # disregard the first layer of X, which is degree 0
        datahat = X[:, 1:].dot(betas[1:, ...]).T
    regressed_data = data - datahat

    # Back to original shape
    return regressed_data.reshape(datashape), non_constant_regressors
示例#24
0
def fit_legendres_images(images,
                         centers,
                         lg_inds,
                         rad_inds,
                         maxPixel,
                         rotate=0,
                         image_stds=None,
                         image_counts=None,
                         image_nanMaps=None,
                         image_weights=None,
                         chiSq_fit=False,
                         rad_range=None):
    """
    Fits legendre polynomials to an array of single images (3d) or a list/array of 
    an array of scan images, possible dimensionality:
        1) [NtimeSteps, image_rows, image_cols]
        2) [NtimeSteps (list), Nscans, image_rows, image_cols]
    """

    if image_counts is None:
        image_counts = []
        for im in range(len(images)):
            image_counts.append(np.ones_like(images[im]))
            image_counts[im][np.isnan(images[im])] = 0

    if chiSq_fit and (image_stds is None):
        print("If using the chiSq fit you must supply image_stds")
        return None

    if image_stds is None:
        image_stds = []
        for im in range(len(images)):
            image_stds.append(np.ones_like(images[im]))
            image_stds[im][np.isnan(images[im])] = 0

    with_scans = len(images[0].shape) + 1 >= 4

    img_fits = [[] for x in range(len(images))]
    img_covs = [[] for x in range(len(images))]
    for rad in range(maxPixel):
        if rad_range is not None:
            if rad < rad_range[0] or rad >= rad_range[1]:
                continue
        if rad % 25 == 0:
            print("Fitting radius {}".format(rad))

        pixels, nans, angles = [], [], []
        all_angles = np.arctan2(rad_inds[rad][1].astype(float),
                                rad_inds[rad][0].astype(float))
        all_angles[all_angles < 0] += 2 * np.pi
        all_angles = np.mod(all_angles + rotate, 2 * np.pi)
        all_angles[all_angles > np.pi] -= 2 * np.pi
        if np.sum(np.mod(lg_inds, 2)) == 0:
            all_angles[np.abs(all_angles) > np.pi / 2.] -= np.pi * np.sign(
                all_angles[np.abs(all_angles) > np.pi / 2.])
        angles = np.unique(np.abs(all_angles))
        ang_sort_inds = np.argsort(angles)
        angles = angles[ang_sort_inds]
        Nangles = angles.shape[0]

        if len(angles) == len(all_angles):
            do_merge = False
        else:
            do_merge = True
            mi_rows, mi_cols, mi_data = [], [], []
            pr, pc, pv = [], [], []
            for ia, ang in enumerate(angles):
                inds = np.where(np.abs(all_angles) == ang)[0]
                mi_rows.append(np.ones_like(inds) * ia)
                mi_cols.append(inds)
            mi_rows, mi_cols = np.concatenate(mi_rows), np.concatenate(mi_cols)

            merge_indices = csr_matrix(
                (np.ones_like(mi_rows), (mi_rows, mi_cols)),
                shape=(len(angles), len(all_angles)))

        for im in range(len(images)):

            if with_scans:
                angs_tile = np.tile(angles, (images[im].shape[0], 1))
                scn_inds, row_inds, col_inds = [], [], []
                for isc in range(images[im].shape[0]):
                    scn_inds.append(
                        np.ones(rad_inds[rad][0].shape[0], dtype=int) * isc)
                    row_inds.append(rad_inds[rad][0] + centers[im][isc, 0])
                    col_inds.append(rad_inds[rad][1] + centers[im][isc, 1])

                scn_inds = np.concatenate(scn_inds)
                row_inds = np.concatenate(row_inds)
                col_inds = np.concatenate(col_inds)
                img_pixels = np.reshape(
                    copy(images[im][scn_inds, row_inds, col_inds]),
                    (images[im].shape[0], -1))
                img_counts = np.reshape(
                    copy(image_counts[im][scn_inds, row_inds, col_inds]),
                    (images[im].shape[0], -1))
                img_stds = np.reshape(
                    copy(image_stds[im][scn_inds, row_inds, col_inds]),
                    (images[im].shape[0], -1))
                if image_nanMaps is not None:
                    img_pixels[np.reshape(
                        image_nanMaps[im][scn_inds, row_inds, col_inds],
                        (images[im].shape[0], -1)).astype(bool)] = np.nan
                    img_counts[np.reshape(
                        image_nanMaps[im][scn_inds, row_inds, col_inds],
                        (images[im].shape[0], -1)).astype(bool)] = 0
                if image_weights is not None:
                    img_weights = np.reshape(
                        copy(image_weights[im][scn_inds, row_inds, col_inds]),
                        (images[im].shape[0], -1))
            else:
                angs_tile = np.expand_dims(angles, 0)
                row_inds = rad_inds[rad][0] + centers[im, 0]
                col_inds = rad_inds[rad][1] + centers[im, 1]
                img_pixels = np.reshape(copy(images[im][row_inds, col_inds]),
                                        (1, -1))
                img_counts = np.reshape(
                    copy(image_counts[im][row_inds, col_inds]), (1, -1))
                img_stds = np.reshape(copy(image_stds[im][row_inds, col_inds]),
                                      (1, -1))
                if image_nanMaps is not None:
                    img_pixels[np.reshape(
                        image_nanMaps[im][row_inds, col_inds],
                        (1, -1)).astype(bool)] = np.nan
                    img_counts[np.reshape(
                        image_nanMaps[im][row_inds, col_inds],
                        (1, -1)).astype(bool)] = 0
                if image_weights is not None:
                    img_weights = np.reshape(
                        copy(image_weights[im][row_inds, col_inds]), (1, -1))

            img_pix = img_pixels * img_counts
            img_var = img_counts * (img_stds**2)
            img_pix[np.isnan(img_pixels)] = 0
            img_var[np.isnan(img_pixels)] = 0

            if do_merge:

                img_pixels[np.isnan(img_pixels)] = 0

                img_pix = np.transpose(merge_indices.dot(
                    np.transpose(img_pix)))
                img_var = np.transpose(merge_indices.dot(
                    np.transpose(img_var)))

                img_counts = np.transpose(
                    merge_indices.dot(np.transpose(img_counts)))

                if image_weights is not None:
                    print("Must fill this in, don't forget std option")
                    sys.exit(0)
            else:
                img_pix = img_pix[:, ang_sort_inds]
                img_var = img_var[:, ang_sort_inds]
                img_counts = img_counts[:, ang_sort_inds]
            img_pix /= img_counts
            img_var /= img_counts

            Nnans = np.sum(np.isnan(img_pix), axis=-1)
            ang_inds = np.where(img_counts > 0)
            arr_inds = np.concatenate(
                [np.arange(Nangles - Nn) for Nn in Nnans])

            img_pixels = np.zeros_like(img_pix)
            img_vars = np.zeros_like(img_var)
            img_angs = np.zeros_like(img_pix)
            img_dang = np.zeros_like(img_pix)

            img_pixels[ang_inds[0][:-1], arr_inds[:-1]] =\
                    (img_pix[ang_inds[0][:-1], ang_inds[1][:-1]] + img_pix[ang_inds[0][1:], ang_inds[1][1:]])/2.
            img_vars[ang_inds[0][:-1], arr_inds[:-1]] =\
                    (img_var[ang_inds[0][:-1], ang_inds[1][:-1]] + img_var[ang_inds[0][1:], ang_inds[1][1:]])/2.
            img_angs[ang_inds[0][:-1], arr_inds[:-1]] =\
                    (angs_tile[ang_inds[0][:-1], ang_inds[1][:-1]] + angs_tile[ang_inds[0][1:], ang_inds[1][1:]])/2.
            img_dang[ang_inds[0][:-1], arr_inds[:-1]] =\
                    (angs_tile[ang_inds[0][1:], ang_inds[1][1:]] - angs_tile[ang_inds[0][:-1], ang_inds[1][:-1]])

            for isc in range(Nnans.shape[0]):
                # Using angle midpoint => one less angle => Nnans[isc]+1
                img_pixels[isc, -1 * (Nnans[isc] + 1):] = 0
                img_vars[isc, -1 * (Nnans[isc] + 1):] = 0
                img_angs[isc, -1 * (Nnans[isc] + 1):] = 0
                img_dang[isc, -1 * (Nnans[isc] + 1):] = 0

            if image_weights is not None:
                print("Must fill this in and check below")
                sys.exit(0)
            elif chiSq_fit:
                img_weights = 1. / img_vars
                img_weights[img_vars == 0] = 0
            else:
                img_weights = np.ones_like(img_pixels)
            img_weights *= np.sin(img_angs) * img_dang
            lgndrs = []
            for lg in lg_inds:
                lgndrs.append(Legendre.basis(lg)(np.cos(img_angs)))
            lgndrs = np.transpose(np.array(lgndrs), (1, 0, 2))

            empty_scan = np.sum(img_weights.astype(bool), -1) < 2
            overlap = np.einsum('bai,bi,bci->bac',
                                lgndrs[np.invert(empty_scan)],
                                img_weights[np.invert(empty_scan)],
                                lgndrs[np.invert(empty_scan)],
                                optimize='greedy')
            empty_scan[np.invert(empty_scan)] = (np.linalg.det(overlap) == 0.0)

            if np.any(empty_scan):
                fit = np.ones((img_pixels.shape[0], len(lg_inds))) * np.nan
                cov = np.ones(
                    (img_pixels.shape[0], len(lg_inds), len(lg_inds))) * np.nan

                if np.any(np.invert(empty_scan)):
                    img_pixels = img_pixels[np.invert(empty_scan)]
                    img_weights = img_weights[np.invert(empty_scan)]
                    img_vars = img_vars[np.invert(empty_scan)]
                    lgndrs = lgndrs[np.invert(empty_scan)]

                    fit[np.invert(empty_scan)], cov[np.invert(empty_scan)] =\
                        normal_eqn_vects(lgndrs, img_pixels, img_weights, img_vars)
            else:
                fit, cov = normal_eqn_vects(lgndrs, img_pixels, img_weights,
                                            img_vars)
            img_fits[im].append(np.expand_dims(fit, 1))
            img_covs[im].append(np.expand_dims(cov, 1))

    Nscans = None
    for im in range(len(img_fits)):
        img_fits[im] = np.concatenate(img_fits[im], 1)
        img_covs[im] = np.concatenate(img_covs[im], 1)
        if Nscans is None:
            Nscans = img_fits[im].shape[0]
        elif Nscans != img_fits[im].shape[0]:
            Nscans = -1
    if Nscans > 0:
        img_fits = np.array(img_fits)
        img_covs = np.array(img_covs)

    if with_scans:
        return img_fits, img_covs
    else:
        return img_fits[:, 0, :, :], img_covs[:, 0, :, :]