Subscripted assignment dimension mismatch.

x = -10:0.1:10;

lower_1 = zeros(numel(x), 2);

upper_1 = zeros(numel(x), 2);

f1 = trapmf(x,[-2 0 0 2]);

[ss, firstmax] = max(f1);

lower_1(1:firstmax, :) = [x(1:firstmax), f1(1:firstmax)];

upper_1(firstmax:end, :) = [x(firstmax:end, :), f1(firstmax:end, :)];

I get a subscripted assignment dimesnion mismatch error. Why is this??

[soloby]

when i type in [x(1:firstmax), f1(1:firstmax)] in matlab, i get a 1x202 matrix for some reason?? should i not be getting a 2xlength(firstmax) matrix?

Answer 1

[Ingrid]

you should do this

lower_1(1:firstmax, :) = [x(1:firstmax)',f1(1:firstmax)'];
upper_1(firstmax:end,:) = [x(firstmax:end)', f1(firstmax:end)'];

since your x is a rowvector and not a columnvector or transpose x first

[soloby]

hey, thanks for an answer

I still get an error on the upper bound

Improper assignment with rectangular empty matrix.

Error in (line 13) upper_1(firstmax:end, :) = [x(firstmax:end, :)', f1(firstmax:end, :)'];

why would this be? it's the same concept pretty much

[cwshep]

It is because firstmax:end is empty (since firstmax is greater than end). To do it this way it would need to be: "upper_1(firstmax:end, :) = [x(:,firstmax:end).', f1(:, firstmax:end).'];"

Note that it's good habit to do a .' than just a ', since if they are complex values the ' does a conjugate transpose.

[Ingrid]

look at what I have shown in the code above you should not index x as x(firstmax:end,:) because this will be empty since x has dimensions 1x201 so just leave out the last :

but even easier would be to FIRST transpose x as I have also commented and then f1 is also a column vector and all subsequent transposes are not required which makes your code easier to maintain

Answer 2

[cwshep]

Your x and f1 arrays are 1x201. Your upper_1 array is 201x2. Presumably you want to do a "x = x.'; f1 = f1.';" before your assignment to lower_1.

Actually, the cleanest and best way is probably to just change your first line to "x = [-10:0.1:10].';"