예제 #1
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def L2error(self, uh, exact, intorder=None):
        """Compute :math:`L^2` error against exact solution.

        The computation is based on the following identity:

        .. math::

            \|u-u_h\|_0^2 = (u,u)+(u_h,u_h)-2(u,u_h).

        Parameters
        ----------
        uh : np.array
            The discrete solution.

        exact : function handle
            The exact solution.

        intorder : (OPTIONAL) int
            The integration order.

        Returns
        -------
        float
            The global :math:`L^2` error.
        """
        if self.elem_u.maxdeg != self.elem_v.maxdeg:
            raise NotImplementedError("elem_u.maxdeg must be elem_v.maxdeg "
                                      "when computing errors!")
        if intorder is None:
            intorder = 2*self.elem_u.maxdeg

        X, W = get_quadrature(self.mesh.refdom, intorder)

        # assemble some helper matrices
        # the idea is to use the identity: (u-uh,u-uh)=(u,u)+(uh,uh)-2(u,uh)
        def uv(u, v):
            return u*v

        def fv(v, x):
            return exact(x)*v

        M = self.iasm(uv)
        f = self.iasm(fv)

        detDF = self.mapping.detDF(X)
        x = self.mapping.F(X)

        uu = np.sum(np.dot(exact(x)**2*np.abs(detDF), W))

        return np.sqrt(uu + np.dot(uh, M.dot(uh)) - 2.*np.dot(uh, f))
예제 #2
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def inorm(self, form, interp, intorder=None):
        # evaluate norm on all elements
        tind = range(self.mesh.t.shape[1])

        if not isinstance(interp, dict):
            raise Exception("The input solution vector(s) must be in a "
                            "dictionary! Pass e.g. {0:u} instead of u.")

        if intorder is None:
            intorder = 2*self.elem_u.maxdeg

        # check and fix parameters of form
        oldparams = inspect.getargspec(form).args
        paramlist = ['u', 'du', 'ddu', 'x', 'h']
        fform = self.fillargs(form, paramlist)

        X, W = get_quadrature(self.mesh.refdom, intorder)

        # mappings
        x = self.mapping.F(X, tind) # reference facet to global facet

        # jacobian at quadrature points
        detDF = self.mapping.detDF(X, tind)

        Nbfun_u = self.dofnum_u.t_dof.shape[0]
        dim = self.mesh.p.shape[0]

        # interpolate the solution vectors at quadrature points
        zero = 0.0*x[0]
        w, dw, ddw = ({} for i in range(3))
        for k in interp:
            w[k] = zero
            dw[k] = const_cell(zero, dim)
            ddw[k] = const_cell(zero, dim, dim)
            for j in range(Nbfun_u):
                jdofs = self.dofnum_u.t_dof[j, :]
                w[k] += interp[k][jdofs][:, None]\
                        * self.u[j]
                for a in range(dim):
                    dw[k][a] += interp[k][jdofs][:, None]\
                                * self.du[j][a]
                    for b in range(dim):
                        ddw[k][a][b] += interp[k][jdofs][:, None]\
                                        * self.ddu[j][a][b]

        # compute the mesh parameter from jacobian determinant
        h = np.abs(detDF)**(1.0/self.mesh.dim())

        return np.dot(fform(w, dw, ddw, x, h)**2*np.abs(detDF), W)
예제 #3
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def __init__(self, mesh, elem_u, elem_v=None, intorder=None):
        if not isinstance(mesh, spfem.mesh.Mesh):
            raise Exception("First parameter must be an instance of "
                            "spfem.mesh.Mesh.")
        if not isinstance(elem_u, spfem.element.AbstractElement):
            raise Exception("Second parameter must be an instance of "
                            "spfem.element.AbstractElement.")
        if elem_v is not None:
            if not isinstance(elem_v, spfem.element.AbstractElement):
                raise Exception("Third parameter must be an instance of "
                                "spfem.element.AbstractElement.")

        self.mesh = mesh
        self.elem_u = elem_u
        self.dofnum_u = Dofnum(mesh, elem_u)
        self.mapping = mesh.mapping()

        # duplicate test function element type if None is given
        if elem_v is None:
            self.elem_v = elem_u
            self.dofnum_v = self.dofnum_u
        else:
            self.elem_v = elem_v
            self.dofnum_v = Dofnum(mesh, elem_v)

        if intorder is None:
            # compute the maximum polynomial degree from elements
            self.intorder = self.elem_u.maxdeg + self.elem_v.maxdeg
        else:
            self.intorder = intorder

        # quadrature points and weights
        X, _ = get_quadrature(self.mesh.refdom, self.intorder)
        # global quadrature points
        x = self.mapping.F(X, range(self.mesh.t.shape[1]))
        # pre-compute basis functions at quadrature points
        self.u, self.du, self.ddu = self.elem_u.evalbasis(self.mesh, x)

        if elem_v is None:
            self.v = self.u
            self.dv = self.du
            self.ddv = self.ddu
        else:
            self.v, self.dv, self.ddv = self.elem_v.evalbasis(self.mesh, x)
예제 #4
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def H1error(self, uh, dexact, intorder=None):
        """Compute :math:`H^1` seminorm error against exact solution.

        The computation is based on the following identity:

        .. math::

            \|\\nabla(u-u_h)\|_0^2 = (\\nabla u,\\nabla u)
                                     + (\\nabla u_h, \\nabla u_h)
                                     - 2(\\nabla u, \\nabla u_h).

        Parameters
        ----------
        uh : np.array
            The discrete solution.

        dexact : function handle
            The derivative of the exact solution.

        intorder : (OPTIONAL) int
            The integration order.

        Returns
        -------
        float
            The global :math:`H^1` error.
        """
        if self.elem_u.maxdeg != self.elem_v.maxdeg:
            raise NotImplementedError("elem_u.maxdeg must be elem_v.maxdeg "
                                      "when computing errors!")
        if intorder is None:
            intorder = 2*self.elem_u.maxdeg

        X, W = get_quadrature(self.mesh.refdom, intorder)

        # assemble some helper matrices
        # the idea is to use the identity: (u-uh,u-uh)=(u,u)+(uh,uh)-2(u,uh)
        def uv(du, dv):
            if not isinstance(du, dict):
                return du*dv
            elif len(du) == 2:
                return du[0]*dv[0] + du[1]*dv[1]
            elif len(du) == 3:
                return du[0]*dv[0] + du[1]*dv[1] + du[2]*dv[2]
            else:
                raise NotImplementedError("AssemblerElement.H1error not "
                                          "implemented for current domain "
                                          "dimension!")

        def fv(dv, x):
            if not isinstance(x, dict):
                return dexact(x)*dv
            elif len(x) == 2:
                return dexact[0](x)*dv[0] + dexact[1](x)*dv[1]
            elif len(x) == 3:
                return dexact[0](x)*dv[0] + dexact[1](x)*dv[1]\
                       + dexact[2](x)*dv[2]
            else:
                raise NotImplementedError("AssemblerElement.H1error not "
                                          "implemented for current domain "
                                          "dimension!")

        M = self.iasm(uv)
        f = self.iasm(fv)

        detDF = self.mapping.detDF(X)
        x = self.mapping.F(X)

        if not isinstance(x, dict):
            uu = np.sum(np.dot((dexact(x)**2) * np.abs(detDF), W))
        elif len(x) == 2:
            uu = np.sum(np.dot((dexact[0](x)**2 + dexact[1](x)**2)
                               * np.abs(detDF), W))
        elif len(x) == 3:
            uu = np.sum(np.dot((dexact[0](x)**2 + dexact[1](x)**2
                                + dexact[2](x)**2) * np.abs(detDF), W))
        else:
            raise NotImplementedError("AssemblerElement.H1error not "
                                      "implemented for current domain "
                                      "dimension!")

        return np.sqrt(uu + np.dot(uh, M.dot(uh)) - 2.*np.dot(uh, f))
예제 #5
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def fasm(self, form, find=None, interior=False, intorder=None,
             normals=True, interp=None):
        """Facet assembly."""
        if find is None:
            if interior:
                find = self.mesh.interior_facets()
            else:
                find = self.mesh.boundary_facets()

        if intorder is None:
            intorder = self.elem_u.maxdeg + self.elem_v.maxdeg

        nv = self.mesh.p.shape[1]
        nt = self.mesh.t.shape[1]
        ne = find.shape[0]

        # check and fix parameters of form
        oldparams = inspect.getargspec(form).args
        if interior:
            if 'u1' in oldparams or 'du1' in oldparams:
                paramlist = ['u1', 'u2', 'v1', 'v2',
                             'du1', 'du2', 'dv1', 'dv2',
                             'x', 'h', 'n', 'w']
                bilinear = True
            else:
                paramlist = ['v1', 'v2', 'dv1', 'dv2',
                             'x', 'h', 'n', 'w']
                bilinear = False
        else:
            if 'u' in oldparams or 'du' in oldparams:
                paramlist = ['u', 'v', 'du', 'dv', 'x', 'h', 'n', 'w']
                bilinear = True
            else:
                paramlist = ['v', 'dv', 'x', 'h', 'n', 'w']
                bilinear = False
        fform = self.fillargs(form, paramlist)

        X, W = get_quadrature(self.mesh.brefdom, intorder)

        # boundary element indices
        tind1 = self.mesh.f2t[0, find]
        tind2 = self.mesh.f2t[1, find]

        # mappings
        x = self.mapping.G(X, find=find) # reference facet to global facet
        Y1 = self.mapping.invF(x, tind=tind1) # global facet to ref element
        Y2 = self.mapping.invF(x, tind=tind2) # global facet to ref element

        Nbfun_u = self.dofnum_u.t_dof.shape[0]
        Nbfun_v = self.dofnum_v.t_dof.shape[0]

        detDG = self.mapping.detDG(X, find)

        # compute normal vectors
        n = {}
        if normals:
            # normals based on tind1 only
            n = self.mapping.normals(Y1, tind1, find, self.mesh.t2f)

        # compute the mesh parameter from jacobian determinant
        if self.mesh.dim() > 1.0:
            h = np.abs(detDG)**(1.0/(self.mesh.dim() - 1.0))
        else: # exception for 1D mesh (no boundary h defined)
            h = None

        # interpolate some previous discrete function at quadrature points
        w = {}
        if interp is not None:
            if not isinstance(interp, dict):
                raise Exception("The input solution vector(s) must be in a "
                                "dictionary! Pass e.g. {0:u} instead of u.")
            for k in interp:
                w[k] = 0.0*x[0]
                for j in range(Nbfun_u):
                    phi, _ = self.elem_u.gbasis(self.mapping, Y1, j, tind1)
                    w[k] += interp[k][self.dofnum_u.t_dof[j, tind1], None]*phi

        # bilinear form
        if bilinear:
            # initialize sparse matrix structures
            ndata = Nbfun_u*Nbfun_v*ne
            if interior:
                data = np.zeros(4*ndata)
                rows = np.zeros(4*ndata)
                cols = np.zeros(4*ndata)
            else:
                data = np.zeros(ndata)
                rows = np.zeros(ndata)
                cols = np.zeros(ndata)

            for j in range(Nbfun_u):
                u1, du1 = self.elem_u.gbasis(self.mapping, Y1, j, tind1)
                if interior:
                    u2, du2 = self.elem_u.gbasis(self.mapping, Y2, j, tind2)
                    if j == 0:
                        # these are zeros corresponding to the shapes of u,du
                        z = const_cell(0, *cell_shape(u2))
                        dz = const_cell(0, *cell_shape(du2))
                for i in range(Nbfun_v):
                    v1, dv1 = self.elem_v.gbasis(self.mapping, Y1, i, tind1)
                    if interior:
                        v2, dv2 = self.elem_v.gbasis(self.mapping, Y2, i, tind2)

                    # compute entries of local stiffness matrices
                    if interior:
                        ixs1 = slice(ne*(Nbfun_v*j + i),
                                     ne*(Nbfun_v*j + i + 1))
                        ixs2 = slice(ne*(Nbfun_v*j + i) + ndata,
                                     ne*(Nbfun_v*j + i + 1) + ndata)
                        ixs3 = slice(ne*(Nbfun_v*j + i) + 2*ndata,
                                     ne*(Nbfun_v*j + i + 1) + 2*ndata)
                        ixs4 = slice(ne*(Nbfun_v*j + i) + 3*ndata,
                                     ne*(Nbfun_v*j + i + 1) + 3*ndata)

                        data[ixs1] = np.dot(fform(u1, z, v1, z,
                                                  du1, dz, dv1, dz,
                                                  x, h, n, w)*np.abs(detDG), W)
                        rows[ixs1] = self.dofnum_v.t_dof[i, tind1]
                        cols[ixs1] = self.dofnum_u.t_dof[j, tind1]

                        data[ixs2] = np.dot(fform(z, u2, z, v2,
                                                  dz, du2, dz, dv2,
                                                  x, h, n, w)*np.abs(detDG), W)
                        rows[ixs2] = self.dofnum_v.t_dof[i, tind2]
                        cols[ixs2] = self.dofnum_u.t_dof[j, tind2]

                        data[ixs3] = np.dot(fform(z, u2, v1, z,
                                                  dz, du2, dv1, dz,
                                                  x, h, n, w)*np.abs(detDG), W)
                        rows[ixs3] = self.dofnum_v.t_dof[i, tind1]
                        cols[ixs3] = self.dofnum_u.t_dof[j, tind2]

                        data[ixs4] = np.dot(fform(u1, z, z, v2,
                                                  du1, dz, dz, dv2,
                                                  x, h, n, w)*np.abs(detDG), W)
                        rows[ixs4] = self.dofnum_v.t_dof[i, tind2]
                        cols[ixs4] = self.dofnum_u.t_dof[j, tind1]
                    else:
                        ixs = slice(ne*(Nbfun_v*j + i), ne*(Nbfun_v*j + i + 1))
                        data[ixs] = np.dot(fform(u1, v1, du1, dv1,
                                                 x, h, n, w)*np.abs(detDG), W)
                        rows[ixs] = self.dofnum_v.t_dof[i, tind1]
                        cols[ixs] = self.dofnum_u.t_dof[j, tind1]

            return coo_matrix((data, (rows, cols)),
                              shape=(self.dofnum_v.N, self.dofnum_u.N)).tocsr()

        # linear form
        else:
            if interior:
                # could not find any use case
                raise Exception("No interior support in linear facet form.")
            # initialize sparse matrix structures
            data = np.zeros(Nbfun_v*ne)
            rows = np.zeros(Nbfun_v*ne)
            cols = np.zeros(Nbfun_v*ne)

            for i in range(Nbfun_v):
                v1, dv1 = self.elem_v.gbasis(self.mapping, Y1, i, tind1)

                # find correct location in data,rows,cols
                ixs = slice(ne*i, ne*(i + 1))

                # compute entries of local stiffness matrices
                data[ixs] = np.dot(fform(v1, dv1, x, h, n, w)*np.abs(detDG), W)
                rows[ixs] = self.dofnum_v.t_dof[i, tind1]
                cols[ixs] = np.zeros(ne)

            return coo_matrix((data, (rows, cols)),
                              shape=(self.dofnum_v.N, 1)).toarray().T[0]
예제 #6
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def iasm(self, form, intorder=None, tind=None, interp=None):
        """Return a matrix related to a bilinear or linear form
        where the integral is over the interior of the domain.

        Parameters
        ----------
        form : function handle
            The bilinear or linear form function handle.
            The supported parameters can be found in the
            following table.

            +-----------+----------------------+--------------+
            | Parameter | Explanation          | Supported in |
            +-----------+----------------------+--------------+
            | u         | solution             | bilinear     |
            +-----------+----------------------+--------------+
            | v         | test fun             | both         |
            +-----------+----------------------+--------------+
            | du        | solution derivatives | bilinear     |
            +-----------+----------------------+--------------+
            | dv        | test fun derivatives | both         |
            +-----------+----------------------+--------------+
            | x         | spatial location     | both         |
            +-----------+----------------------+--------------+
            | w         | cf. interp           | both         |
            +-----------+----------------------+--------------+
            | h         | the mesh parameter   | both         |
            +-----------+----------------------+--------------+

            The function handle must use these exact names for
            the variables. Unused variable names can be omitted.

            Examples of valid bilinear forms:
            ::

                def bilin_form1(du, dv):
                    # Note that the element must be
                    # defined for two-dimensional
                    # meshes for this to make sense!
                    return du[0]*dv[0] + du[1]*dv[1]

                def bilin_form2(du, v):
                    return du[0]*v

                bilin_form3 = lambda u, v, x: x[0]**2*u*v

            Examples of valid linear forms:
            ::

                def lin_form1(v):
                    return v

                def lin_form2(h, x, v):
                    import numpy as np
                    mesh_parameter = h
                    X = x[0]
                    Y = x[1]
                    return mesh_parameter*np.sin(np.pi*X)*np.sin(np.pi*Y)*v

            The linear forms are automatically detected to be
            non-bilinear through the omission of u or du.

        intorder : int
            The order of polynomials for which the applied
            quadrature rule is exact. By default,
            2*Element.maxdeg is used. Reducing this number
            can sometimes reduce the computation time.

        interp : numpy array
            Using this flag, the user can provide
            a solution vector that is interpolated
            to the quadrature points and included in
            the computation of the bilinear form
            (the variable w). Useful e.g. when solving
            nonlinear problems.
        """
        if tind is None:
            # assemble on all elements by default
            tind = range(self.mesh.t.shape[1])
        nt = len(tind)
        if intorder is None:
            # compute the maximum polynomial degree from elements
            intorder = self.elem_u.maxdeg + self.elem_v.maxdeg

        # check and fix parameters of form
        oldparams = inspect.getargspec(form).args
        if 'u' in oldparams or 'du' in oldparams:
            paramlist = ['u', 'v', 'du', 'dv', 'x', 'w', 'h']
            bilinear = True
        else:
            paramlist = ['v', 'dv', 'x', 'w', 'h']
            bilinear = False
        fform = self.fillargs(form, paramlist)

        # quadrature points and weights
        X, W = get_quadrature(self.mesh.refdom, intorder)

        # global quadrature points
        x = self.mapping.F(X, tind)

        # jacobian at quadrature points
        detDF = self.mapping.detDF(X, tind)

        Nbfun_u = self.dofnum_u.t_dof.shape[0]
        Nbfun_v = self.dofnum_v.t_dof.shape[0]

        # interpolate some previous discrete function at quadrature points
        w = {}
        if interp is not None:
            if not isinstance(interp, dict):
                raise Exception("The input solution vector(s) must be in a "
                                "dictionary! Pass e.g. {0:u} instead of u.")
            for k in interp:
                w[k] = 0.0*x[0]
                for j in range(Nbfun_u):
                    phi, _ = self.elem_u.lbasis(X, j)
                    w[k] += np.outer(interp[k][self.dofnum_u.t_dof[j, :]], phi)

        # compute the mesh parameter from jacobian determinant
        h = np.abs(detDF)**(1.0/self.mesh.dim())

        # bilinear form
        if bilinear:
            # initialize sparse matrix structures
            data = np.zeros(Nbfun_u*Nbfun_v*nt)
            rows = np.zeros(Nbfun_u*Nbfun_v*nt)
            cols = np.zeros(Nbfun_u*Nbfun_v*nt)

            for j in range(Nbfun_u):
                u, du = self.elem_u.gbasis(self.mapping, X, j, tind)
                for i in range(Nbfun_v):
                    v, dv = self.elem_v.gbasis(self.mapping, X, i, tind)

                    # find correct location in data,rows,cols
                    ixs = slice(nt*(Nbfun_v*j+i), nt*(Nbfun_v*j+i+1))

                    # compute entries of local stiffness matrices
                    data[ixs] = np.dot(fform(u, v, du, dv, x, w, h)
                                       * np.abs(detDF), W)
                    rows[ixs] = self.dofnum_v.t_dof[i, tind]
                    cols[ixs] = self.dofnum_u.t_dof[j, tind]

            return coo_matrix((data, (rows, cols)),
                              shape=(self.dofnum_v.N, self.dofnum_u.N)).tocsr()

        else:
            # initialize sparse matrix structures
            data = np.zeros(Nbfun_v*nt)
            rows = np.zeros(Nbfun_v*nt)
            cols = np.zeros(Nbfun_v*nt)

            for i in range(Nbfun_v):
                v, dv = self.elem_v.gbasis(self.mapping, X, i, tind)

                # find correct location in data,rows,cols
                ixs = slice(nt*i, nt*(i+1))

                # compute entries of local stiffness matrices
                data[ixs] = np.dot(fform(v, dv, x, w, h)*np.abs(detDF), W)
                rows[ixs] = self.dofnum_v.t_dof[i, :]
                cols[ixs] = np.zeros(nt)

            return coo_matrix((data, (rows, cols)),
                              shape=(self.dofnum_v.N, 1)).toarray().T[0]
예제 #7
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def fnorm(self, form, interp, intorder=None, interior=False, normals=True):
        if interior:
            # evaluate norm on all interior facets
            find = self.mesh.interior_facets()
        else:
            # evaluate norm on all boundary facets
            find = self.mesh.boundary_facets()

        if not isinstance(interp, dict):
            raise Exception("The input solution vector(s) must be in a "
                            "dictionary! Pass e.g. {0:u} instead of u.")

        if intorder is None:
            intorder = 2*self.elem_u.maxdeg

        # check and fix parameters of form
        oldparams = inspect.getargspec(form).args
        if 'u1' in oldparams or 'du1' in oldparams or 'ddu1' in oldparams:
            if interior is False:
                raise Exception("The supplied form contains u1 although "
                                "no interior=True is given.")
        if interior:
            paramlist = ['u1', 'u2', 'du1', 'du2', 'ddu1', 'ddu2',
                         'x', 'n', 't', 'h']
        else:
            paramlist = ['u', 'du', 'ddu', 'x', 'n', 't', 'h']
        fform = self.fillargs(form, paramlist)

        X, W = get_quadrature(self.mesh.brefdom, intorder)

        # indices of elements at different sides of facets
        tind1 = self.mesh.f2t[0, find]
        tind2 = self.mesh.f2t[1, find]

        # mappings
        x = self.mapping.G(X, find=find) # reference facet to global facet
        detDG = self.mapping.detDG(X, find)

        # compute basis function values at quadrature points
        u1, du1, ddu1 = self.elem_u.evalbasis(self.mesh, x, tind=tind1)
        if interior:
            u2, du2, ddu2 = self.elem_u.evalbasis(self.mesh, x, tind=tind2)

        Nbfun_u = self.dofnum_u.t_dof.shape[0]
        dim = self.mesh.p.shape[0]

        n = {}
        t = {}
        if normals:
            Y = self.mapping.invF(x, tind=tind1) # global facet to ref element
            n = self.mapping.normals(Y, tind1, find, self.mesh.t2f)
            if len(n) == 2: # TODO fix for 3D and other than triangles?
                t[0] = -n[1]
                t[1] = n[0]

        # interpolate the solution vectors at quadrature points
        zero = np.zeros((len(find), len(W)))
        w1, dw1, ddw1 = ({} for i in range(3))
        if interior:
            w2, dw2, ddw2 = ({} for i in range(3))
        for k in interp:
            w1[k] = zero
            dw1[k] = const_cell(zero, dim)
            ddw1[k] = const_cell(zero, dim, dim)
            if interior:
                w2[k] = zero
                dw2[k] = const_cell(zero, dim)
                ddw2[k] = const_cell(zero, dim, dim)
            for j in range(Nbfun_u):
                jdofs1 = self.dofnum_u.t_dof[j, tind1]
                jdofs2 = self.dofnum_u.t_dof[j, tind2]
                w1[k] += interp[k][jdofs1][:, None] * u1[j]
                if interior:
                    w2[k] += interp[k][jdofs2][:, None] * u2[j]
                for a in range(dim):
                    dw1[k][a] += interp[k][jdofs1][:, None]\
                                 * du1[j][a]
                    if interior:
                        dw2[k][a] += interp[k][jdofs2][:, None]\
                                     * du2[j][a]
                    for b in range(dim):
                        ddw1[k][a][b] += interp[k][jdofs1][:, None]\
                                         * ddu1[j][a][b]
                        if interior:
                            ddw2[k][a][b] += interp[k][jdofs2][:, None]\
                                             * ddu2[j][a][b]

        h = np.abs(detDG)**(1.0/(self.mesh.dim()-1.0))

        if interior:
            return np.dot(fform(w1, w2, dw1, dw2, ddw1, ddw2,
                                x, n, t, h)**2*np.abs(detDG), W), find
        else:
            return np.dot(fform(w1, dw1, ddw1,
                                x, n, t, h)**2*np.abs(detDG), W), find
예제 #8
0
파일: assembly.py 프로젝트: kinnala/sp.fem
    def iasm(self, form, tind=None, interp=None):
        if tind is None:
            # assemble on all elements by default
            tind = range(self.mesh.t.shape[1])
        nt = len(tind)

        # check and fix parameters of form
        oldparams = inspect.getargspec(form).args
        if 'u' in oldparams or 'du' in oldparams or 'ddu' in oldparams:
            paramlist = ['u', 'v', 'du', 'dv', 'ddu', 'ddv', 'x', 'w', 'h']
            bilinear = True
        else:
            paramlist = ['v', 'dv', 'ddv', 'x', 'w', 'h']
            bilinear = False
        fform = self.fillargs(form, paramlist)

        # quadrature points and weights
        X, W = get_quadrature(self.mesh.refdom, self.intorder)

        # global quadrature points
        x = self.mapping.F(X, tind)

        # jacobian at quadrature points
        detDF = self.mapping.detDF(X, tind)

        Nbfun_u = self.dofnum_u.t_dof.shape[0]
        Nbfun_v = self.dofnum_v.t_dof.shape[0]

        # interpolate some previous discrete function at quadrature points
        w = {}
        if interp is not None:
            if not isinstance(interp, dict):
                raise Exception("The input solution vector(s) must be in a "
                                "dictionary! Pass e.g. {0:u} instead of u.")
            # interpolate the solution vectors at quadrature points
            zero = 0.0*x[0]
            w = {}
            for k in interp:
                w[k] = zero
                for j in range(self.Nbfun_u):
                    jdofs = self.dofnum_u.t_dof[j, :]
                    w[k] += interp[k][jdofs][:, None]*self.u[j]

        # compute the mesh parameter from jacobian determinant
        h = np.abs(detDF)**(1.0/self.mesh.dim())

        # bilinear form
        if bilinear:
            # initialize sparse matrix structures
            data = np.zeros(Nbfun_u*Nbfun_v*nt)
            rows = np.zeros(Nbfun_u*Nbfun_v*nt)
            cols = np.zeros(Nbfun_u*Nbfun_v*nt)

            for j in range(Nbfun_u):
                for i in range(Nbfun_v):
                    # find correct location in data,rows,cols
                    ixs = slice(nt*(Nbfun_v*j + i), nt*(Nbfun_v*j + i + 1))

                    # compute entries of local stiffness matrices
                    data[ixs] = np.dot(fform(self.u[j], self.v[i],
                                             self.du[j], self.dv[i],
                                             self.ddu[j], self.ddv[i],
                                             x, w, h)*np.abs(detDF), W)
                    rows[ixs] = self.dofnum_v.t_dof[i, tind]
                    cols[ixs] = self.dofnum_u.t_dof[j, tind]

            return coo_matrix((data, (rows, cols)),
                              shape=(self.dofnum_v.N, self.dofnum_u.N)).tocsr()

        else:
            # initialize sparse matrix structures
            data = np.zeros(Nbfun_v*nt)
            rows = np.zeros(Nbfun_v*nt)
            cols = np.zeros(Nbfun_v*nt)

            for i in range(Nbfun_v):
                # find correct location in data,rows,cols
                ixs = slice(nt*i, nt*(i + 1))

                # compute entries of local stiffness matrices
                data[ixs] = np.dot(fform(self.v[i], self.dv[i], self.ddv[i],
                                         x, w, h)*np.abs(detDF), W)
                rows[ixs] = self.dofnum_v.t_dof[i, :]
                cols[ixs] = np.zeros(nt)

            return coo_matrix((data, (rows, cols)),
                              shape=(self.dofnum_v.N, 1)).toarray().T[0]