Inconsistent dimensions of arrays

Hi. I am trying to add the Park Transformation matrix to my m file but it won't run. The error message reads:

>> Park_Transformation_matrix

Error using vertcat

Dimensions of arrays being concatenated are not consistent.

Error in Park_Transformation_matrix (line 4)

Park_1 = [cos(theta) cos(theta-(2*pi/3)) cos(theta+(2*pi/3));

My code is simply the matrix itself:

theta=0:0.01:2*pi;

Park_1 = (2/3)*[cos(theta) cos(theta-(2*pi/3)) cos(theta+(2*pi/3));

-sin(theta) -sin(theta-(2*pi/3)) -sin(theta+(2*pi/3));

0.5 0.5 0.5];

Answer 1

[the cyclist]

Note what the upper-left element of your array is:

theta=0:0.01:2*pi;
cos(theta)

ans = 1×629

1.0000 1.0000 0.9998 0.9996 0.9992 0.9988 0.9982 0.9976 0.9968 0.9960 0.9950 0.9940 0.9928 0.9916 0.9902 0.9888 0.9872 0.9856 0.9838 0.9820 0.9801 0.9780 0.9759 0.9737 0.9713 0.9689 0.9664 0.9638 0.9611 0.9582

So, you are trying to concatenate two rows that have 1,887 elements with one row that has 3 elements.

It looks like you intended to create the matrix as a function of theta. You can do this as follows:

Park_1 = @(theta) ((2/3)*[cos(theta),  cos(theta-(2*pi/3)),  cos(theta+(2*pi/3)); ...
                         -sin(theta), -sin(theta-(2*pi/3)), -sin(theta+(2*pi/3)); ...
                              0.5,             0.5,                     0.5    ]);

Park_1(pi)

ans = 3×3

-0.6667 0.3333 0.3333 -0.0000 -0.5774 0.5774 0.3333 0.3333 0.3333

You still cannot call this with a vector theta, though. Depending on how you want to use this in a next step, you may need to code it differently.

Answer 2

[Walter Roberson]

Your theta is on the order of 625 elements long. What size are you expecting sin(theta) to be? What size are you expecting 0.5 0.5 0.5 to be?