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CentOS 7.0 - man page for dlanv2 (centos section 3)

dlanv2.f(3)							      LAPACK							       dlanv2.f(3)

NAME
dlanv2.f -
SYNOPSIS
Functions/Subroutines subroutine dlanv2 (A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN) DLANV2 computes the Schur factorization of a real 2-by-2 nonsymmetric matrix in standard form. Function/Subroutine Documentation subroutine dlanv2 (double precisionA, double precisionB, double precisionC, double precisionD, double precisionRT1R, double precisionRT1I, double precisionRT2R, double precisionRT2I, double precisionCS, double precisionSN) DLANV2 computes the Schur factorization of a real 2-by-2 nonsymmetric matrix in standard form. Purpose: DLANV2 computes the Schur factorization of a real 2-by-2 nonsymmetric matrix in standard form: [ A B ] = [ CS -SN ] [ AA BB ] [ CS SN ] [ C D ] [ SN CS ] [ CC DD ] [-SN CS ] where either 1) CC = 0 so that AA and DD are real eigenvalues of the matrix, or 2) AA = DD and BB*CC < 0, so that AA + or - sqrt(BB*CC) are complex conjugate eigenvalues. Parameters: A A is DOUBLE PRECISION B B is DOUBLE PRECISION C C is DOUBLE PRECISION D D is DOUBLE PRECISION On entry, the elements of the input matrix. On exit, they are overwritten by the elements of the standardised Schur form. RT1R RT1R is DOUBLE PRECISION RT1I RT1I is DOUBLE PRECISION RT2R RT2R is DOUBLE PRECISION RT2I RT2I is DOUBLE PRECISION The real and imaginary parts of the eigenvalues. If the eigenvalues are a complex conjugate pair, RT1I > 0. CS CS is DOUBLE PRECISION SN SN is DOUBLE PRECISION Parameters of the rotation matrix. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Further Details: Modified by V. Sima, Research Institute for Informatics, Bucharest, Romania, to reduce the risk of cancellation errors, when computing real eigenvalues, and to ensure, if possible, that abs(RT1R) >= abs(RT2R). Definition at line 128 of file dlanv2.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.2 Tue Sep 25 2012 dlanv2.f(3)