Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?larrr
Performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues.
Syntax
call slarrr ( n , d , e , info )
call dlarrr ( n , d , e , info )
Include Files
mkl.fi
Description
slarrr dlarrr
The routine performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues.
Input Parameters
- n
-
INTEGER . The order of the matrix T . ( n> 0 ).
- d
-
REAL for slarrr DOUBLE PRECISION for dlarrr Array, DIMENSION ( n ). Contains n diagonal elements of the matrix T .
- e
-
REAL for slarrr DOUBLE PRECISION for dlarrr Array, DIMENSION ( n ). The first (n-1) entries contain sub-diagonal elements of the tridiagonal matrix T ; e(n) is set to 0.
Output Parameters
info
INTEGER .
= 0: the matrix warrants computations preserving relative accuracy (default value).
= -1: the matrix warrants computations guaranteeing only absolute accuracy.