slartgs.f(3) LAPACK slartgs.f(3)NAMEslartgs.f -SYNOPSISFunctions/Subroutines subroutine slartgs (X, Y, SIGMA, CS, SN) SLARTGS Function/Subroutine Documentation subroutine slartgs (realX, realY, realSIGMA, realCS, realSN) SLARTGS Purpose: SLARTGS generates a plane rotation designed to introduce a bulge in Golub-Reinsch-style implicit QR iteration for the bidiagonal SVD problem. X and Y are the top-row entries, and SIGMA is the shift. The computed CS and SN define a plane rotation satisfying [ CS SN ] . [ X^2 - SIGMA ] = [ R ], [ -SN CS ] [ X * Y ] [ 0 ] with R nonnegative. If X^2 - SIGMA and X * Y are 0, then the rotation is by PI/2. Parameters: X X is REAL The (1,1) entry of an upper bidiagonal matrix. Y Y is REAL The (1,2) entry of an upper bidiagonal matrix. SIGMA SIGMA is REAL The shift. CS CS is REAL The cosine of the rotation. SN SN is REAL The sine of the rotation. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: November 2011 Definition at line 91 of file slartgs.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.1 Sun May 26 2013 slartgs.f(3)