Description

Namespace with classes for the modal module.

Classes
class	callback_Ax
	Generic A*x callback. More...

class	callback_Ax_sparse_complexshiftinvert
	The callback to be used for "Ax" where for shift&invert is: A = (As - sigma Bs)/Bs , with COMPLEX sigma shift, so Ax = (As - sigma Bs)/(Bsx), just like a linear system with coefficient matrix (As - sigma Bs) and known rhs Bsx. More...

class	callback_Ax_sparse_shiftinvert
	The callback to be used for "Ax" where for shift&invert is: A = (As - sigma Bs)/Bs , so Ax = (As - sigma Bs)/(Bsx), just like a linear system with coefficient matrix (As - sigma Bs) and known rhs Bsx. More...

class	ChGeneralizedEigenvalueSolver
	Base interface class for generalized eigenvalue solvers Ax = lambdaB*x. More...

class	ChKrylovSchurEig
	Compute (complex) eigenvalues and eigenvectors using the Krylov-Schur algorithm. More...

class	ChModalAssembly
	Class for assemblies of items, for example ChBody, ChLink, ChMesh, etc. More...

class	ChModalDamping
	Base class for damping models of modal reduced assemblies. More...

class	ChModalDampingCustom
	Class for damping defined with an user-defined matrix that could be obtained via external tools such as Matlab or FEA. More...

class	ChModalDampingFactorAssembly
	Class for setting the damping via N damping factors z_i for all the modes of the subassembly, where assembly n.modes = (boundary coords+internal modes) R^ = V'^-1 * Dd * V^-1 with Dd=diag { 2 z_1 w_1, 2 z_2 w_2, ..., 2 z_i w_i }, and V = eigenvectors of (M^, K^). More...

class	ChModalDampingFactorRayleigh
	Class for setting the damping via N damping factors z_i of the internal mode coordinates and alpha-beta Rayleigh damping for the boundary nodes, assuming R^ = [Rbb Rbm ] [Rmb Rmm ] with Rmm=diag { 2 z_1 w_1, 2 z_2 w_2, ..., 2 z_i w_i }, Rbb= alphaMbb + betaKbb, Rbm = 0, Rmb = 0. More...

class	ChModalDampingFactorRmm
	Class for setting the damping via N damping factors z_i of the internal mode coordinates. More...

class	ChModalDampingNone
	Class for no damping model. More...

class	ChModalDampingRayleigh
	Class for simple Rayleigh damping model R^ = alphaM^ + betaK^ where M^ and K^ are the reduced matrices, both for boundary nodes and modal coords. More...

class	ChModalDampingReductionR
	Class for damping as reduction of the original damping matrix via the eigenvectors of the undamped assembly, i.e. More...

class	ChModalSolver
	Base class for modal solvers. More...

class	ChModalSolverDamped
	Modal solver for damped systems of the form (-w^2M + iwR + K)x = 0 s.t. More...

class	ChModalSolverUndamped
	Modal solver for undamped systems (-w^2M+K)x = 0 s.t. More...

class	ChSymGenEigenvalueSolver
	Base interface class for iterative eigenvalue solvers for generalized problem with real symmetric matrices. More...

class	ChSymGenEigenvalueSolverKrylovSchur
	Generalized iterative eigenvalue solver implementing Krylov-Schur shift-and-invert method for real symmetric matrices. More...

class	ChSymGenEigenvalueSolverLanczos
	Generalized iterative eigenvalue solver implementing Lanczos shift-and-invert method for real symmetric matrices. More...

class	ChUnsymGenEigenvalueSolver
	Base interface class for iterative eigenvalue solvers for generalized problem with real generic matrices. More...

class	ChUnsymGenEigenvalueSolverKrylovSchur
	Generalized iterative eigenvalue solver implementing Krylov-Schur shift-and-invert method for real generic matrices. More...

Functions
template<typename EigSolverType >
int	Solve (EigSolverType &eig_solver, ChSparseMatrix &A, ChSparseMatrix &B, ChMatrixDynamic< typename EigSolverType::ScalarType > &eigvects, ChVectorDynamic< typename EigSolverType::ScalarType > &eigvals, const std::list< std::pair< int, typename EigSolverType::ScalarType >> &eig_requests, bool uniquify=true, int eigvects_clipping_length=0)
	Helper function to solve any kind of generalized eigenvalue problem even with multiple requests. More...

void	ordschur (ChMatrixDynamic< std::complex< double >> &U, ChMatrixDynamic< std::complex< double >> &T, ChVectorDynamic< bool > &select)

int	testConverge (ChMatrixDynamic< std::complex< double >> &H, int k, int i, double tol)

void	truncateKrylov (ChMatrixDynamic< std::complex< double >> &Q, ChMatrixDynamic< std::complex< double >> &H, const int k, const int m)

void	sortSchur (ChMatrixDynamic< std::complex< double >> &US, ChMatrixDynamic< std::complex< double >> &TS, bool &isC, const ChMatrixDynamic< std::complex< double >> &A, const int k)

void	expandKrylov (ChMatrixDynamic< std::complex< double >> &Q, ChMatrixDynamic< std::complex< double >> &H, callback_Ax *Ax_function, int sk, int ek)

void	KrylovSchur (ChMatrixDynamic< std::complex< double >> &Q, ChMatrixDynamic< std::complex< double >> &H, bool &isC, bool &flag, int &nc, int &ni, callback_Ax *Ax_function, const ChVectorDynamic< std::complex< double >> &v1, const int n, const int k, const int m, const int maxIt, const double tol)

void	swap (ChModalAssembly &first, ChModalAssembly &second)

void	util_sparse_assembly_2x2symm (ChSparseMatrix &HCQ, const ChSparseMatrix &H, const ChSparseMatrix &Cq, bool resize_and_reserve=true)

void	util_convert_to_colmajor (Eigen::SparseMatrix< double, Eigen::ColMajor, int > &H_col, const ChSparseMatrix &H)

void	BuildDampedEigenProblemMatrices (ChAssembly &assembly, ChSystemDescriptor &temp_descriptor, ChSparseMatrix &A, ChSparseMatrix &B, int n_vars)
	Partially build the damped eigenvalue problem matrices A and B from a given ChAssembly. More...

void	BuildUndampedEigenProblemMatrices (ChAssembly &assembly, ChSystemDescriptor &temp_descriptor, ChSparseMatrix &A, ChSparseMatrix &B, int n_vars)
	Partially build the undamped eigenvalue problem matrices A and B from a given ChAssembly. More...

void	CountNonZerosForEachRow (const ChSparseMatrix &Q, Eigen::VectorXi &nonZerosPerRow, int offset)

void	CountNonZerosForEachRowTransposed (const ChSparseMatrix &Q_transp, Eigen::VectorXi &nonZerosPerRow, int offset)

Function Documentation

◆ BuildDampedEigenProblemMatrices()

void chrono::modal::BuildDampedEigenProblemMatrices	(	ChAssembly &	assembly,
		ChSystemDescriptor &	temp_descriptor,
		ChSparseMatrix &	A,
		ChSparseMatrix &	B,
		int	n_vars
	)

Partially build the damped eigenvalue problem matrices A and B from a given ChAssembly.

WARNING: Cq and Cq' signs are not flipped here: the user is expected to flip it during scaling (if any) The final shape of the matrices is:

A = [ 0 I 0 ] [ -K -R -Cq' ] [ -Cq 0 0 ]

B = [ I 0 0 ] [ 0 M 0 ] [ 0 0 0 ]

◆ BuildUndampedEigenProblemMatrices()

void ChApiModal chrono::modal::BuildUndampedEigenProblemMatrices	(	ChAssembly &	assembly,
		ChSystemDescriptor &	temp_descriptor,
		ChSparseMatrix &	A,
		ChSparseMatrix &	B,
		int	n_vars
	)

Partially build the undamped eigenvalue problem matrices A and B from a given ChAssembly.

Utility function to build the A and B matrices for the undamped eigenvalue problem.

WARNING: Cq and Cq' signs are not flipped here: the user is expected to flip it during scaling (if any). The finale shape should be: A = [ -K -Cq' ] [ -Cq 0 ]

B = [ M 0 ] [ 0 0 ]

◆ Solve()

template<typename EigSolverType >

int chrono::modal::Solve	(	EigSolverType &	eig_solver,
		ChSparseMatrix &	A,
		ChSparseMatrix &	B,
		ChMatrixDynamic< typename EigSolverType::ScalarType > &	eigvects,
		ChVectorDynamic< typename EigSolverType::ScalarType > &	eigvals,
		const std::list< std::pair< int, typename EigSolverType::ScalarType >> &	eig_requests,
		bool	uniquify = `true`,
		int	eigvects_clipping_length = `0`
	)

Helper function to solve any kind of generalized eigenvalue problem even with multiple requests.

The eigenvectors are also filtered to avoid duplicates with the same frequency. This means that only one of the complex eigenvectors that come in conjugate pairs is stored. The eigrequest argument is a list of pairs, where the first element is the number of modes to be found, and the second element is the shift to apply for that specific search.

◆ swap()

void chrono::modal::swap	(	ChModalAssembly &	first,
		ChModalAssembly &	second
	)

Implemented as a friend (as opposed to a member function) so classes with a ChModalAssembly member can use ADL when implementing their own swap.

◆ util_convert_to_colmajor()

void chrono::modal::util_convert_to_colmajor	(	Eigen::SparseMatrix< double, Eigen::ColMajor, int > &	H_col,
		const ChSparseMatrix &	H
	)

Parameters

H_col	resulting sparse matrix (column major)
H	input sparse matrix (row major)

◆ util_sparse_assembly_2x2symm()

void chrono::modal::util_sparse_assembly_2x2symm	(	ChSparseMatrix &	HCQ,
		const ChSparseMatrix &	H,
		const ChSparseMatrix &	Cq,
		bool	resize_and_reserve = `true`
	)