eigvals Interface

experimental
38 statements
Source File

public interface eigvals

Returns the eigenvalues $lambda$ , $A \cdot \bar{v} - \lambda \cdot \bar{v}$ , for square matrix $A$ . (Specification)

Summary

Function interface for computing the eigenvalues of a square matrix.

Description

This interface provides functions for returning the eigenvalues of a general square matrix. Supported data types include real and complex, and no assumption is made on the matrix structure. An error stop is thrown in case of failure; otherwise, error information can be returned as an optional type(linalg_state_type) output flag.

Note

The solution is based on LAPACK's general eigenproblem solvers *GEEV.

Note

BLAS/LAPACK backends do not currently support extended precision (xdp).

Functions

private module function stdlib_linalg_eigvals_c(a, err) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
complex(kind=sp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]
type(linalg_state_type),	intent(out)			::	err	[optional] state return flag. On error if not requested, the code will stop

Return Value complex(kind=sp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_d(a, err) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=dp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]
type(linalg_state_type),	intent(out)			::	err	[optional] state return flag. On error if not requested, the code will stop

Return Value complex(kind=dp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_noerr_c(a) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
complex(kind=sp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]

Return Value complex(kind=sp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_noerr_d(a) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=dp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]

Return Value complex(kind=dp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_noerr_s(a) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=sp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]

Return Value complex(kind=sp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_noerr_z(a) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
complex(kind=dp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]

Return Value complex(kind=dp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_s(a, err) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=sp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]
type(linalg_state_type),	intent(out)			::	err	[optional] state return flag. On error if not requested, the code will stop

Return Value complex(kind=sp), allocatable, (:)

Array of singular values

private module function stdlib_linalg_eigvals_z(a, err) result(lambda)

Return an array of eigenvalues of matrix A.

Arguments

Type	Intent	Optional	Attributes		Name
complex(kind=dp),	intent(in),		target	::	a(:,:)	Input matrix A[m,n]
type(linalg_state_type),	intent(out)			::	err	[optional] state return flag. On error if not requested, the code will stop

Return Value complex(kind=dp), allocatable, (:)

Array of singular values