Description of slrotmat

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slrotmat

PURPOSE

SLROTMAT Get the 2x2 rotation matrix

SYNOPSIS

function R = slrotmat(theta)

DESCRIPTION

SLROTMAT Get the 2x2 rotation matrix

 $ Syntax $
   - R = slrotmat(theta)

 $ Arguments $
   - theta:      the radian of rotation
   - R:          the rotation matrix

 $ Description $
   - R = slrotmat(theta) computes the 2x2 rotation matrix R which
     rotates a 2D point anti-clockwisely by radian of theta. 
     If theta is a scalar, then R will be a 2x2 matrix, if
     theta is an n1 x n2 x ... array, then R will be a set of 
     matrices stored in an 2 x 2 x n1 x n2 x ... array.

 $ Remarks $
   - The R is given by following formula:
     R = [ cos(theta)   -sin(theta);
           sin(theta)    cos(theta) ];

 $ History $
   - Created by Dahua Lin on Apr 23, 2006

CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

SOURCE CODE

0001 function R = slrotmat(theta)
0002 %SLROTMAT Get the 2x2 rotation matrix
0003 %
0004 % $ Syntax $
0005 %   - R = slrotmat(theta)
0006 %
0007 % $ Arguments $
0008 %   - theta:      the radian of rotation
0009 %   - R:          the rotation matrix
0010 %
0011 % $ Description $
0012 %   - R = slrotmat(theta) computes the 2x2 rotation matrix R which
0013 %     rotates a 2D point anti-clockwisely by radian of theta.
0014 %     If theta is a scalar, then R will be a 2x2 matrix, if
0015 %     theta is an n1 x n2 x ... array, then R will be a set of
0016 %     matrices stored in an 2 x 2 x n1 x n2 x ... array.
0017 %
0018 % $ Remarks $
0019 %   - The R is given by following formula:
0020 %     R = [ cos(theta)   -sin(theta);
0021 %           sin(theta)    cos(theta) ];
0022 %
0023 % $ History $
0024 %   - Created by Dahua Lin on Apr 23, 2006
0025 %
0026 
0027 if isscalar(theta)  % single
0028     R = [cos(theta), -sin(theta);
0029          sin(theta),  cos(theta)];
0030 else % multiple
0031     TM = reshape(theta, [1, 1, size(theta)]);
0032     CM = cos(TM);
0033     SM = sin(TM);
0034     R = [CM, -SM;
0035          SM,  CM];
0036 end
0037 
0038     
0039 
0040

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