Problem when assigning vectors

Hi,

i want to do this:

b=zeros(size(f),1)

b=f(k);

And i get this error:

Index exceeds matrix dimensions.

I print the size of each variable and this is the result:

size(f)= 500 1;

size(k)= 500 1;

size(b)= 500 1; %Here, i get this warning:

           %Warning: Input arguments must be scalar.

Can anyone explain me why am i returned this result? How could i fix my mistake and make b=f(k); works??

Thank you in advance.

[Azzi Abdelmalek]

can you post a sample of your data

[Mike]

Which ones?? f?? Do you want results of my signal f?? or my signal?

[Azzi Abdelmalek]

f and k

Answer 1

[John Petersen]

the value of k must be positive and less than the size of f.

[Mike]

Thank you, but how could i fix the error. I do not understand why this error exists as each vector has size [ 500 1 ].

Answer 2

[José-Luis]

b = zeros(numel(f),1);

[Mike]

Thank you. Now i do not get the warning i wrote above. but the error still exists.

[José-Luis]

Try

   max(k)

Given your error, the value returned should be larger than the size of f. You are trying to access elements of f beyond the defined range. I recommend you read the getting started part of the documentation to understand indexing.

[Mike]

Thank you for your help.

Answer 3

[Loren Shure]

First, Mike, there is no reason to preallocate the vector b with zeros since you overwrite the variable in the next statement.

Second, as pointed out above, the first input to zeros needs to be a scalar value.

And finally, also pointed out above, the value for k can't exceed the number of values in f.

So, I guess (and I think others above have too) that your value for k is larger than the number of elements in f. Perhaps you can post a bit more of the code so we can see better what is happening.

[Mike]

Thank you for your reply. I just try to preallocate the b in case i fix tmy mistake. But, i understand it is not needed.

I write:

display(max(k));

and i got the result: 4991. So, you are right.

Thank you.