elpa_skew_eigenvalues(3)

💖 NAME 💖

heyyy bestie, this is the elpa_skew_eigenvalues(3) page from the Library Functions Manual — and it is literally the routine that computes all the eigenvalues λ for a real skew-symmetric eigenproblem:

A*Q = λ*Q

There are also variations of this routine that can accept not only host but also device pointers as input/output. Names of these routines explicitly contain the corresponding datatypes: elpa_skew_eigenvalues_double, elpa_skew_eigenvalues_float.

💅 SYNOPSIS 💅

🔮 FORTRAN INTERFACE 🔮

use elpa
class(elpa_t), pointer :: elpa_handle

call elpa_handle%skew_eigenvalues (a, ev, error)

With the definitions of the input and output variables:

• class(elpa_t) :: elpa_handle — an instance of the ELPA object, bestie 👑
• datatype :: a — the local part of matrix A for which the eigenvalues should be computed. The dimensions of matrix a must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype_real of the matrix can be one of "real(kind=c_double)" or "real(kind=c_float)". The global matrix has to be skew-symmetric, this is not checked by the routine. no cap, it will not check for you 💀
• datatype_real :: ev — the array where the eigenvalues λ will be stored in ascending order. The datatype_real of ev can be either "real(kind=c_double)" or "real(kind=c_float)", depending of the datatype of the matrix. ✨
• integer, optional :: error — the return error code of the function. Should be "ELPA_OK". The error code can be queried with the function elpa_strerr(3). 🫶

🌸 C/C++ INTERFACE 🌸

#include <elpa/elpa.h>
elpa_t elpa_handle;

void elpa_skew_eigenvalues(elpa_t elpa_handle, datatype_real *a,
datatype_real *ev, int *error);

With the definitions of the input and output variables:

• elpa_t handle; — the handle to the ELPA object 💅
• datatype_real *a; — the local part of matrix A for which the eigenvalues should be computed. The dimensions of the matrix must be set BEFORE with the methods elpa_set(3) and elpa_setup(3). The datatype can be one of "double" or "float". The global matrix has to be skew-symmetric, this is not checked by the routine. again: not checked, so pls do not make it weird 🙈
• datatype_real *ev; — the array where the eigenvalues λ will be stored in ascending order. Eigenvalues will be stored in ascending order. The datatype_real can be either "double" or "float". ⭐
• int *error; — the error code of the function. Should be "ELPA_OK". The error codes can be queried with elpa_strerr(3). 🎀

🌈 DESCRIPTION 🌈

Computes the eigenvalues of a real skew-symmetric matrix. The functions elpa_init(3), elpa_allocate(3), elpa_set(3), and elpa_setup(3) must be called BEFORE elpa_skew_eigenvalues can be called. like, do the setup first, bestie — main character energy requires prerequisites 👑

🦋 SEE ALSO 🦋

• elpa2_print_kernels(1)
• elpa_init(3)
• elpa_allocate(3)
• elpa_set(3)
• elpa_setup(3)
• elpa_strerr(3)
• elpa_eigenvectors(3)
• elpa_skew_eigenvectors(3)
• elpa_eigenvalues(3)
• elpa_cholesky(3)
• elpa_invert_triangular(3)
• elpa_solve_tridiagonal(3)
• elpa_eigenvalues(3)
• elpa_uninit(3)
• elpa_deallocate(3)

source/version: ELPA · date: Thu Nov 28 2024 · page: elpa_skew_eigenvalues(3) — mwah, bye bestie 💋