org.netlib.lapack
Class Dlasr
java.lang.Object
org.netlib.lapack.Dlasr
public class Dlasr
- extends java.lang.Object
Following is the description from the original
Fortran source. For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact seymour@cs.utk.edu with any questions.
* ..
*
* Purpose
* =======
*
* DLASR applies a sequence of plane rotations to a real matrix A,
* from either the left or the right.
*
* When SIDE = 'L', the transformation takes the form
*
* A := P*A
*
* and when SIDE = 'R', the transformation takes the form
*
* A := A*P**T
*
* where P is an orthogonal matrix consisting of a sequence of z plane
* rotations, with z = M when SIDE = 'L' and z = N when SIDE = 'R',
* and P**T is the transpose of P.
*
* When DIRECT = 'F' (Forward sequence), then
*
* P = P(z-1) * ... * P(2) * P(1)
*
* and when DIRECT = 'B' (Backward sequence), then
*
* P = P(1) * P(2) * ... * P(z-1)
*
* where P(k) is a plane rotation matrix defined by the 2-by-2 rotation
*
* R(k) = ( c(k) s(k) )
* = ( -s(k) c(k) ).
*
* When PIVOT = 'V' (Variable pivot), the rotation is performed
* for the plane (k,k+1), i.e., P(k) has the form
*
* P(k) = ( 1 )
* ( ... )
* ( 1 )
* ( c(k) s(k) )
* ( -s(k) c(k) )
* ( 1 )
* ( ... )
* ( 1 )
*
* where R(k) appears as a rank-2 modification to the identity matrix in
* rows and columns k and k+1.
*
* When PIVOT = 'T' (Top pivot), the rotation is performed for the
* plane (1,k+1), so P(k) has the form
*
* P(k) = ( c(k) s(k) )
* ( 1 )
* ( ... )
* ( 1 )
* ( -s(k) c(k) )
* ( 1 )
* ( ... )
* ( 1 )
*
* where R(k) appears in rows and columns 1 and k+1.
*
* Similarly, when PIVOT = 'B' (Bottom pivot), the rotation is
* performed for the plane (k,z), giving P(k) the form
*
* P(k) = ( 1 )
* ( ... )
* ( 1 )
* ( c(k) s(k) )
* ( 1 )
* ( ... )
* ( 1 )
* ( -s(k) c(k) )
*
* where R(k) appears in rows and columns k and z. The rotations are
* performed without ever forming P(k) explicitly.
*
* Arguments
* =========
*
* SIDE (input) CHARACTER*1
* Specifies whether the plane rotation matrix P is applied to
* A on the left or the right.
* = 'L': Left, compute A := P*A
* = 'R': Right, compute A:= A*P**T
*
* PIVOT (input) CHARACTER*1
* Specifies the plane for which P(k) is a plane rotation
* matrix.
* = 'V': Variable pivot, the plane (k,k+1)
* = 'T': Top pivot, the plane (1,k+1)
* = 'B': Bottom pivot, the plane (k,z)
*
* DIRECT (input) CHARACTER*1
* Specifies whether P is a forward or backward sequence of
* plane rotations.
* = 'F': Forward, P = P(z-1)*...*P(2)*P(1)
* = 'B': Backward, P = P(1)*P(2)*...*P(z-1)
*
* M (input) INTEGER
* The number of rows of the matrix A. If m <= 1, an immediate
* return is effected.
*
* N (input) INTEGER
* The number of columns of the matrix A. If n <= 1, an
* immediate return is effected.
*
* C (input) DOUBLE PRECISION array, dimension
* (M-1) if SIDE = 'L'
* (N-1) if SIDE = 'R'
* The cosines c(k) of the plane rotations.
*
* S (input) DOUBLE PRECISION array, dimension
* (M-1) if SIDE = 'L'
* (N-1) if SIDE = 'R'
* The sines s(k) of the plane rotations. The 2-by-2 plane
* rotation part of the matrix P(k), R(k), has the form
* R(k) = ( c(k) s(k) )
* ( -s(k) c(k) ).
*
* A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
* The M-by-N matrix A. On exit, A is overwritten by P*A if
* SIDE = 'R' or by A*P**T if SIDE = 'L'.
*
* LDA (input) INTEGER
* The leading dimension of the array A. LDA >= max(1,M).
*
* =====================================================================
*
* .. Parameters ..
Constructor Summary |
Dlasr()
|
Method Summary |
static void |
dlasr(java.lang.String side,
java.lang.String pivot,
java.lang.String direct,
int m,
int n,
double[] c,
int _c_offset,
double[] s,
int _s_offset,
double[] a,
int _a_offset,
int lda)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Dlasr
public Dlasr()
dlasr
public static void dlasr(java.lang.String side,
java.lang.String pivot,
java.lang.String direct,
int m,
int n,
double[] c,
int _c_offset,
double[] s,
int _s_offset,
double[] a,
int _a_offset,
int lda)