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# dlar2v

```
NAME
DLAR2V - apply a vector of real plane rotations from both
sides to a sequence of 2-by-2 real symmetric matrices,
defined by the elements of the vectors x, y and z

SYNOPSIS
SUBROUTINE DLAR2V( N, X, Y, Z, INCX, C, S, INCC )

INTEGER        INCC, INCX, N

DOUBLE         PRECISION C( * ), S( * ), X( * ), Y( * ),
Z( * )

PURPOSE
DLAR2V applies a vector of real plane rotations from both
sides to a sequence of 2-by-2 real symmetric matrices,
defined by the elements of the vectors x, y and z. For i =
1,2,...,n

( x(i)  z(i) ) := (  c(i)  s(i) ) ( x(i)  z(i) ) ( c(i)
-s(i) )
( z(i)  y(i) )    ( -s(i)  c(i) ) ( z(i)  y(i) ) ( s(i)
c(i) )

ARGUMENTS
N       (input) INTEGER
The number of plane rotations to be applied.

X       (input/output) DOUBLE PRECISION array,
dimension (1+(N-1)*INCX) The vector x.

Y       (input/output) DOUBLE PRECISION array,
dimension (1+(N-1)*INCX) The vector y.

Z       (input/output) DOUBLE PRECISION array,
dimension (1+(N-1)*INCX) The vector z.

INCX    (input) INTEGER
The increment between elements of X, Y and Z. INCX >
0.

C       (input) DOUBLE PRECISION array, dimension (1+(N-
1)*INCC)
The cosines of the plane rotations.

S       (input) DOUBLE PRECISION array, dimension (1+(N-
1)*INCC)
The sines of the plane rotations.

INCC    (input) INTEGER
The increment between elements of C and S. INCC > 0.
```