```%% Example: Rotate EPANET Inp File
clc; close all; clear all;

start_toolkit;
d = epanet('Net1.inp');

%Plot nework initial
h = d.plot;

% Rotate degrees theta
theta = pi/2; %90 degrees
for theta = 0:pi/20:pi*2
% define the x- and y-data for the original line we would like to rotate
x = d.getNodeCoordinates{1}';
y = d.getNodeCoordinates{2}';

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% ****
% create a matrix of these points, which will be useful in future calculations
v = [x;y];
% choose a point which will be the center of rotation
x_center = x(1);
y_center = y(1);
% create a matrix which will be used later in calculations
center = repmat([x_center; y_center], 1, length(x));
% define a 60 degree counter-clockwise rotation matrix
% theta = pi/3; % pi/3 radians = 60 degrees
R = [cos(theta) -sin(theta); sin(theta) cos(theta)];
% do the rotation...
s = v - center; % shift points in the plane so that the center of rotation is at the origin
so = R*s; % apply the rotation about the origin
vo = so + center; % shift again so the origin goes back to the desired center of rotation
% this can be done in one line as:
% vo = R*(v - center) + center
% pick out the vectors of rotated x- and y-data
x_new = vo(1,:);
y_new = vo(2,:);
% ****
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

for i=1:d.NodeCount
d.setNodeCoordinates(i, [x_new(i) y_new(i)]);
end

% Plot rotated network
cla;
d.plot('axes', h)
pause(.05)
end
% d.saveInputFile('rotated.inp');

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