GNU/Linux |
CentOS 4.8 |
i386 |
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slartg(l) |
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SLARTG - generate a plane rotation so that [ CS SN ]
SUBROUTINE SLARTG( |
F, G, CS, SN, R ) |
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REAL |
CS, F, G, R, SN |
SLARTG generate a plane rotation so that [ CS SN ] . [ F ] = [ R ] where CS**2 + SN**2 = 1. [ -SN CS ] [ G ] [ 0 ]
This is a
slower, more accurate version of the BLAS1 routine SROTG,
with the following other differences:
F and G are unchanged on return.
If G=0, then CS=1 and SN=0.
If F=0 and (G .ne. 0), then CS=0 and SN=1 without doing any
floating point operations (saves work in SBDSQR when
there are zeros on the diagonal).
If F exceeds G in magnitude, CS will be positive.
F (input) REAL
The first component of vector to be rotated.
G (input) REAL
The second component of vector to be rotated.
CS (output) REAL
The cosine of the rotation.
SN (output) REAL
The sine of the rotation.
R (output) REAL
The nonzero component of the rotated vector.
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slartg(l) | ![]() |