How to Solve RESHAPE Function Error

I am trying to use a reshape function

If i use this syntax

plmprofile1=reshape(plmprofile1,90,180);

the function works well but i am trying to make this function more dynamic so when i created two integer variables nxint = 180 and nyint = 90

and using this syntax

plmprofile1=reshape(plmprofile1,nyint,nxint);

the code didn't work well and this error appeared

To RESHAPE the number of elements must not change.

[Walter Roberson]

That looks like it should work, but at the time of failure please show us the output of

size(plmprofile1)
nyint
nxint

Answer 1

[James Tursa]

Either:

1) The total number of elements of plmprofile1 is different between the reshape(plmprofile1,90,180) call and the reshape(plmprofile1,nyint,nxint) call

or

2) The variables nyint and nxint really don't contain the values you think they do.

To debug this problem, do the following. At the command line prompt issue the following:

dbstop if error

Then run your code. When the error is encountered, the code will pause with all variables intact. Examine size(plmprofile1) and the values of nyint and nxint to see what is really going on.

[Khaled AbdEldayem]

There is no different

but it works when i use nx and ny (they are float not integer values)

[Khaled AbdEldayem]

the variables contain the values as 8 bit integers

[Walter Roberson]

It does not seem to make any difference in my tests whether the size variables are uint8 or double.

Please go through the debugging steps I indicated, showing us

size(plmprofile1)
nyint
nxint

Answer 2

[Image Analyst]

It works fine for me, either with numbers or variables:

% Create an array with 16,000 elements.
plmprofile1 = rand(45, 360); 
% Reshape to 90 by 180.
plmprofile1a = reshape(plmprofile1, 90, 180);
% Reshape to 90 by 180.
nxint = 180 
nyint = 90
plmprofile1b = reshape(plmprofile1, nyint, nxint);

What did you do differently?

[Khaled AbdEldayem]

nxint and nyint are float numbers not integer

while nxint and nyint in my code is a 8 bit integer variables

[Image Analyst]

So it's solved now, right? You understand what's going on, right? You can't take a set of, say, 10 elements and rearrange them into a matrix 4.123 columns wide by 18.334567 rows high. If you want to get a new matrix at some fractional columns and rows, then you'll have to use interp2(), griddedInterpolant(), or imresize(). You'll have to figure out what the new number of rows and columns will be, and they must be integers, for your new, interpolated matrix.

[Walter Roberson]

I think Khaled is talking about the difference between

nxint = 180

and

nxint = uint8(180)

which is something that makes no difference in my testing.

[Image Analyst]

You could be right. When I said

nxint = 180 
nyint = 90

and asked the difference, and he said "nxint and nyint are float numbers not integer" I assume he meant that he had fractional parts off the integer, because everyone knows (or should know) that saying the above means that the variables are floating point doubles, even if they store integer values. Though maybe Khaled didn't know that.

But like Walter, in my tests, with the original uploaded resolution I didn't encounter any black frames. If Khaled wants to dive into it more then he might have to open a case with tech support since neither of us can reproduce his problem.

[Walter Roberson]

I could not read the file at all in MATLAB on my Mac.