CeedBasis

A CeedBasis defines the discrete finite element basis and associated quadrature rule.

Discrete element bases and quadrature

typedef struct CeedBasis_private *CeedBasis

Handle for object describing discrete finite element evaluations.

const CeedBasis CEED_BASIS_NONE = &ceed_basis_none

Argument for CeedOperatorSetField() indicating that the field does not require a CeedBasis

int CeedBasisCreateTensorH1(Ceed ceed, CeedInt dim, CeedInt num_comp, CeedInt P_1d, CeedInt Q_1d, const CeedScalar *interp_1d, const CeedScalar *grad_1d, const CeedScalar *q_ref_1d, const CeedScalar *q_weight_1d, CeedBasis *basis)

Create a tensor-product basis for \(H^1\) discretizations.

User Functions

Parameters:

  • ceed – [in] Ceed object used to create the CeedBasis

  • dim – [in] Topological dimension

  • num_comp – [in] Number of field components (1 for scalar fields)

  • P_1d – [in] Number of nodes in one dimension

  • Q_1d – [in] Number of quadrature points in one dimension

  • interp_1d – [in] Row-major (Q_1d * P_1d) matrix expressing the values of nodal basis functions at quadrature points

  • grad_1d – [in] Row-major (Q_1d * P_1d) matrix expressing derivatives of nodal basis functions at quadrature points

  • q_ref_1d – [in] Array of length Q_1d holding the locations of quadrature points on the 1D reference element [-1, 1]

  • q_weight_1d – [in] Array of length Q_1d holding the quadrature weights on the reference element

  • basis – [out] Address of the variable where the newly created CeedBasis will be stored

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisCreateTensorH1Lagrange(Ceed ceed, CeedInt dim, CeedInt num_comp, CeedInt P, CeedInt Q, CeedQuadMode quad_mode, CeedBasis *basis)

Create a tensor-product \(H^1\) Lagrange basis.

User Functions

Parameters:

  • ceed – [in] Ceed object used to create the CeedBasis

  • dim – [in] Topological dimension of element

  • num_comp – [in] Number of field components (1 for scalar fields)

  • P – [in] Number of Gauss-Lobatto nodes in one dimension. The polynomial degree of the resulting Q_k element is k = P - 1.

  • Q – [in] Number of quadrature points in one dimension.

  • quad_mode – [in] Distribution of the Q quadrature points (affects order of accuracy for the quadrature)

  • basis – [out] Address of the variable where the newly created CeedBasis will be stored

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisCreateH1(Ceed ceed, CeedElemTopology topo, CeedInt num_comp, CeedInt num_nodes, CeedInt num_qpts, const CeedScalar *interp, const CeedScalar *grad, const CeedScalar *q_ref, const CeedScalar *q_weight, CeedBasis *basis)

Create a non tensor-product basis for \(H^1\) discretizations.

User Functions

Parameters:

  • ceed – [in] Ceed object used to create the CeedBasis

  • topo – [in] Topology of element, e.g. hypercube, simplex, etc

  • num_comp – [in] Number of field components (1 for scalar fields)

  • num_nodes – [in] Total number of nodes

  • num_qpts – [in] Total number of quadrature points

  • interp – [in] Row-major (num_qpts * num_nodes) matrix expressing the values of nodal basis functions at quadrature points

  • grad – [in] Row-major (dim * num_qpts * num_nodes) matrix expressing derivatives of nodal basis functions at quadrature points

  • q_ref – [in] Array of length num_qpts * dim holding the locations of quadrature points on the reference element

  • q_weight – [in] Array of length num_qpts holding the quadrature weights on the reference element

  • basis – [out] Address of the variable where the newly created CeedBasis will be stored

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisCreateHdiv(Ceed ceed, CeedElemTopology topo, CeedInt num_comp, CeedInt num_nodes, CeedInt num_qpts, const CeedScalar *interp, const CeedScalar *div, const CeedScalar *q_ref, const CeedScalar *q_weight, CeedBasis *basis)

Create a non tensor-product basis for \(H(\mathrm{div})\) discretizations.

User Functions

Parameters:

  • ceed – [in] Ceed object used to create the CeedBasis

  • topo – [in] Topology of element (CEED_TOPOLOGY_QUAD, CEED_TOPOLOGY_PRISM, etc.), dimension of which is used in some array sizes below

  • num_comp – [in] Number of components (usually 1 for vectors in H(div) bases)

  • num_nodes – [in] Total number of nodes (DoFs per element)

  • num_qpts – [in] Total number of quadrature points

  • interp – [in] Row-major (dim * num_qpts * num_nodes) matrix expressing the values of basis functions at quadrature points

  • div – [in] Row-major (num_qpts * num_nodes) matrix expressing divergence of basis functions at quadrature points

  • q_ref – [in] Array of length num_qpts * dim holding the locations of quadrature points on the reference element

  • q_weight – [in] Array of length num_qpts holding the quadrature weights on the reference element

  • basis – [out] Address of the variable where the newly created CeedBasis will be stored

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisCreateHcurl(Ceed ceed, CeedElemTopology topo, CeedInt num_comp, CeedInt num_nodes, CeedInt num_qpts, const CeedScalar *interp, const CeedScalar *curl, const CeedScalar *q_ref, const CeedScalar *q_weight, CeedBasis *basis)

Create a non tensor-product basis for \(H(\mathrm{curl})\) discretizations.

User Functions

Parameters:

  • ceed – [in] Ceed object used to create the CeedBasis

  • topo – [in] Topology of element (CEED_TOPOLOGY_QUAD, CEED_TOPOLOGY_PRISM, etc.), dimension of which is used in some array sizes below

  • num_comp – [in] Number of components (usually 1 for vectors in \(H(\mathrm{curl})\) bases)

  • num_nodes – [in] Total number of nodes (DoFs per element)

  • num_qpts – [in] Total number of quadrature points

  • interp – [in] Row-major (dim * num_qpts * num_nodes) matrix expressing the values of basis functions at quadrature points

  • curl – [in] Row-major (curl_comp * num_qpts * num_nodes, curl_comp = 1 if dim < 3 otherwise curl_comp = dim) matrix expressing curl of basis functions at quadrature points

  • q_ref – [in] Array of length num_qpts * dim holding the locations of quadrature points on the reference element

  • q_weight – [in] Array of length num_qpts holding the quadrature weights on the reference element

  • basis – [out] Address of the variable where the newly created CeedBasis will be stored

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisCreateProjection(CeedBasis basis_from, CeedBasis basis_to, CeedBasis *basis_project)

Create a CeedBasis for projection from the nodes of basis_from to the nodes of basis_to.

Only CEED_EVAL_INTERP will be valid for the new basis, basis_project. For \(H^1\) spaces, CEED_EVAL_GRAD will also be valid. The interpolation is given by interp_project = interp_to^+ * interp_from, where the pseudoinverse interp_to^+ is given by QR factorization. The gradient (for the \(H^1\) case) is given by grad_project = interp_to^+ * grad_from.

Note: basis_from and basis_to must have compatible quadrature spaces.

Note: basis_project will have the same number of components as basis_from, regardless of the number of components that basis_to has. If basis_from has 3 components and basis_to has 5 components, then basis_project will have 3 components.

Note: If either basis_from or basis_to are non-tensor, then basis_project will also be non-tensor

User Functions

Parameters:

  • basis_from – [in] CeedBasis to prolong from

  • basis_to – [in] CeedBasis to prolong to

  • basis_project – [out] Address of the variable where the newly created CeedBasis will be stored

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisReferenceCopy(CeedBasis basis, CeedBasis *basis_copy)

Copy the pointer to a CeedBasis.

Note: If the value of *basis_copy passed into this function is non-NULL, then it is assumed that *basis_copy is a pointer to a CeedBasis. This CeedBasis will be destroyed if *basis_copy is the only reference to this CeedBasis.

User Functions

Parameters:

  • basis – [in] CeedBasis to copy reference to

  • basis_copy – [inout] Variable to store copied reference

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisSetNumViewTabs(CeedBasis basis, CeedInt num_tabs)

Set the number of tabs to indent for CeedBasisView() output.

User Functions

Parameters:

  • basis – [in] CeedBasis to set the number of view tabs

  • num_tabs – [in] Number of view tabs to set

Returns:

Error code: 0 - success, otherwise - failure

int CeedBasisGetNumViewTabs(CeedBasis basis, CeedInt *num_tabs)

Get the number of tabs to indent for CeedBasisView() output.

User Functions

Parameters:

  • basis – [in] CeedBasis to get the number of view tabs

  • num_tabs – [out] Number of view tabs

Returns:

Error code: 0 - success, otherwise - failure

int CeedBasisView(CeedBasis basis, FILE *stream)

View a CeedBasis

User Functions

Parameters:

  • basis – [in] CeedBasis to view

  • stream – [in] Stream to view to, e.g., stdout

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisApply(CeedBasis basis, CeedInt num_elem, CeedTransposeMode t_mode, CeedEvalMode eval_mode, CeedVector u, CeedVector v)

Apply basis evaluation from nodes to quadrature points or vice versa.

User Functions

Parameters:
Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisApplyAdd(CeedBasis basis, CeedInt num_elem, CeedTransposeMode t_mode, CeedEvalMode eval_mode, CeedVector u, CeedVector v)

Apply basis evaluation from quadrature points to nodes and sum into target vector.

User Functions

Parameters:
Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisApplyAtPoints(CeedBasis basis, CeedInt num_elem, const CeedInt *num_points, CeedTransposeMode t_mode, CeedEvalMode eval_mode, CeedVector x_ref, CeedVector u, CeedVector v)

Apply basis evaluation from nodes to arbitrary points.

User Functions

Parameters:

  • basis – [in] CeedBasis to evaluate

  • num_elem – [in] The number of elements to apply the basis evaluation to; the backend will specify the ordering in CeedElemRestrictionCreate()

  • num_points – [in] Array of the number of points to apply the basis evaluation to in each element, size num_elem

  • t_mode – [in] CEED_NOTRANSPOSE to evaluate from nodes to points; CEED_TRANSPOSE to apply the transpose, mapping from points to nodes

  • eval_mode – [in] CEED_EVAL_INTERP to use interpolated values, CEED_EVAL_GRAD to use gradients, CEED_EVAL_WEIGHT to use quadrature weights

  • x_ref – [in] CeedVector holding reference coordinates of each point

  • u – [in] Input CeedVector, of length num_nodes * num_comp for CEED_NOTRANSPOSE

  • v – [out] Output CeedVector, of length num_points * num_q_comp for CEED_NOTRANSPOSE with CEED_EVAL_INTERP

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisApplyAddAtPoints(CeedBasis basis, CeedInt num_elem, const CeedInt *num_points, CeedTransposeMode t_mode, CeedEvalMode eval_mode, CeedVector x_ref, CeedVector u, CeedVector v)

Apply basis evaluation from nodes to arbitrary points and sum into target vector.

User Functions

Parameters:
Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetCeed(CeedBasis basis, Ceed *ceed)

Get the Ceed associated with a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • ceed – [out] Variable to store Ceed

Returns:

An error code: 0 - success, otherwise - failure

Ceed CeedBasisReturnCeed(CeedBasis basis)

Return the Ceed associated with a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

Returns:

Ceed associated with the basis

int CeedBasisGetDimension(CeedBasis basis, CeedInt *dim)

Get dimension for given CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • dim – [out] Variable to store dimension of basis

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetTopology(CeedBasis basis, CeedElemTopology *topo)

Get topology for given CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • topo – [out] Variable to store topology of basis

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetNumComponents(CeedBasis basis, CeedInt *num_comp)

Get number of components for given CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • num_comp – [out] Variable to store number of components

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetNumNodes(CeedBasis basis, CeedInt *P)

Get total number of nodes (in dim dimensions) of a CeedBasis

Utility Functions

Parameters:

  • basis – [in] CeedBasis

  • P – [out] Variable to store number of nodes

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetNumNodes1D(CeedBasis basis, CeedInt *P_1d)

Get total number of nodes (in 1 dimension) of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • P_1d – [out] Variable to store number of nodes

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetNumQuadraturePoints(CeedBasis basis, CeedInt *Q)

Get total number of quadrature points (in dim dimensions) of a CeedBasis

Utility Functions

Parameters:

  • basis – [in] CeedBasis

  • Q – [out] Variable to store number of quadrature points

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetNumQuadraturePoints1D(CeedBasis basis, CeedInt *Q_1d)

Get total number of quadrature points (in 1 dimension) of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • Q_1d – [out] Variable to store number of quadrature points

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetQRef(CeedBasis basis, const CeedScalar **q_ref)

Get reference coordinates of quadrature points (in dim dimensions) of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • q_ref – [out] Variable to store reference coordinates of quadrature points

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetQWeights(CeedBasis basis, const CeedScalar **q_weight)

Get quadrature weights of quadrature points (in dim dimensions) of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • q_weight – [out] Variable to store quadrature weights

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetInterp(CeedBasis basis, const CeedScalar **interp)

Get interpolation matrix of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • interp – [out] Variable to store interpolation matrix

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetInterp1D(CeedBasis basis, const CeedScalar **interp_1d)

Get 1D interpolation matrix of a tensor product CeedBasis

Backend Developer Functions

Parameters:

  • basis – [in] CeedBasis

  • interp_1d – [out] Variable to store interpolation matrix

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetGrad(CeedBasis basis, const CeedScalar **grad)

Get gradient matrix of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • grad – [out] Variable to store gradient matrix

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetGrad1D(CeedBasis basis, const CeedScalar **grad_1d)

Get 1D gradient matrix of a tensor product CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • grad_1d – [out] Variable to store gradient matrix

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetDiv(CeedBasis basis, const CeedScalar **div)

Get divergence matrix of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • div – [out] Variable to store divergence matrix

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisGetCurl(CeedBasis basis, const CeedScalar **curl)

Get curl matrix of a CeedBasis

Advanced Functions

Parameters:

  • basis – [in] CeedBasis

  • curl – [out] Variable to store curl matrix

Returns:

An error code: 0 - success, otherwise - failure

int CeedBasisDestroy(CeedBasis *basis)

Destroy a CeedBasis: fully discrete finite element-like objects.

User Functions

Parameters:

  • basis – [inout] CeedBasis to destroy

Returns:

An error code: 0 - success, otherwise - failure

int CeedGaussQuadrature(CeedInt Q, CeedScalar *q_ref_1d, CeedScalar *q_weight_1d)

Construct a Gauss-Legendre quadrature.

Utility Functions

Parameters:

  • Q – [in] Number of quadrature points (integrates polynomials of degree 2*Q-1 exactly)

  • q_ref_1d – [out] Array of length Q to hold the abscissa on [-1, 1]

  • q_weight_1d – [out] Array of length Q to hold the weights

Returns:

An error code: 0 - success, otherwise - failure

int CeedLobattoQuadrature(CeedInt Q, CeedScalar *q_ref_1d, CeedScalar *q_weight_1d)

Construct a Gauss-Legendre-Lobatto quadrature.

Utility Functions

Parameters:

  • Q – [in] Number of quadrature points (integrates polynomials of degree 2*Q-3 exactly)

  • q_ref_1d – [out] Array of length Q to hold the abscissa on [-1, 1]

  • q_weight_1d – [out] Array of length Q to hold the weights

Returns:

An error code: 0 - success, otherwise - failure

Typedefs and Enumerations

enum CeedTransposeMode

Denotes whether a linear transformation or its transpose should be applied.

Values:

enumerator CEED_NOTRANSPOSE

Apply the linear transformation.

enumerator CEED_TRANSPOSE

Apply the transpose.

enum CeedEvalMode

Basis evaluation mode.

Values:

enumerator CEED_EVAL_NONE

Perform no evaluation (either because there is no data or it is already at quadrature points)

enumerator CEED_EVAL_INTERP

Interpolate from nodes to quadrature points.

enumerator CEED_EVAL_GRAD

Evaluate gradients at quadrature points from input in the basis.

enumerator CEED_EVAL_DIV

Evaluate divergence at quadrature points from input in the basis.

enumerator CEED_EVAL_CURL

Evaluate curl at quadrature points from input in the basis.

enumerator CEED_EVAL_WEIGHT

Using no input, evaluate quadrature weights on the reference element.

enum CeedQuadMode

Type of quadrature; also used for location of nodes.

Values:

enumerator CEED_GAUSS

Gauss-Legendre quadrature.

enumerator CEED_GAUSS_LOBATTO

Gauss-Legendre-Lobatto quadrature.

enum CeedElemTopology

Type of basis shape to create non-tensor element basis.

Dimension can be extracted with bitwise AND (CeedElemTopology & 2**(dim + 2)) == TRUE

Values:

enumerator CEED_TOPOLOGY_LINE

Line.

enumerator CEED_TOPOLOGY_TRIANGLE

Triangle - 2D shape.

enumerator CEED_TOPOLOGY_QUAD

Quadralateral - 2D shape.

enumerator CEED_TOPOLOGY_TET

Tetrahedron - 3D shape.

enumerator CEED_TOPOLOGY_PYRAMID

Pyramid - 3D shape.

enumerator CEED_TOPOLOGY_PRISM

Prism - 3D shape.

enumerator CEED_TOPOLOGY_HEX

Hexehedron - 3D shape.