Transformations of a Large matrix

I have a very long matrix, 2 x1000 double.

I wish to rotate it, and project it - simply - aka like my linear transformations in linear algebra, see minimalistic code

but all solutions I have found are either

• for square matrices, or
• image-related, and then I would just copy/paste, I wish to understand what I´m doing.

Can this be done?

A = Matrixfilename
x = A(1,:)
y = A(2,:)
plot(x,y,'.')  % gives a figure of a logo

% reflect on x-axis
B = flipud(A)
x2a = B(1,:)
y2a = B(2,:)
plot(x2a,y2a,'.')

% stretching on x-axis
plot(x.*2,y,'r.');

% rotate 140CCW

% project A onto plane N=[1,2,3]

[Walter Roberson]

% reflect on x-axis
B = flipud(A)
x2a = B(1,:)
y2a = B(2,:)

That does not reflect on x axes. That exchanges x and y, which is reflection on x=y axes.

Answer 1

[Walter Roberson]

You have rotation and scale but no translation. You can formulate as

[x(:), y(:)] * A

where A is a 2x2 matrix and * is matrix multiplication. 1000x2 * 2x2 gives 1000x2, which you would split into xprime yprime

For example

A = [0 2; 1 0]

would exchange x and y and multiply the new x by 2

[Jessica]

Thank You so much for this :D

with the added bonus, for me, that it was a quick reply ^^