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From: Samuel on 27 Feb 2010 12:44
Given a 2D matrix A, I need to write a function that displays a subsection of the matrix subA given the following inputs:
A – A 2-D matrix. [r,c] = size(A) where r>=i+m and c>=j+n
i – An integer scalar. A row number in A were the requested subsection begins.
j – An integer scalar. A column number in A were the requested subsection
begins.
m – the number of rows in the subsection
n – the number of column in the subsection
Anybody have any ideas on where I can find more information on this or how I can write this code? Thanks for all your help!
From: Oleg Komarov on 27 Feb 2010 12:48
"Samuel " <boo161620(a)yahoo.com> wrote in message <hmbl64$686$1(a)fred.mathworks.com>...
> I am knew at writing matlab code, and I have this problem. Given a 2D matrix, A, of any size [r,c]=size(A), I need to be able to write a function that finds a sub-section of the matrix A from the given inputs,
> 1. i=scalar, the row where the sub section begins,
> 2. j=scalar, the column where the sub section begins
> 3. m= number of rows in the sub-section
> 4. n= number of columns in the sub-section
>
> From this the function must output the subsection of the matrix, subA. Does anyone know where I can find a method to do this?

On the getting started guide, in the matrix indexing guide and in the function guide (google them).

BTW

function OUT = foo(A, i, j, m, n)
OUT = A(i:i+m, j:j+n)
end

Oleg
From: Samuel on 27 Feb 2010 12:57
"Oleg Komarov" <oleg.komarovRemove.this(a)hotmail.it> wrote in message <hmblsk$kat$1(a)fred.mathworks.com>...
> "Samuel " <boo161620(a)yahoo.com> wrote in message <hmbl64$686$1(a)fred.mathworks.com>...
> > I am knew at writing matlab code, and I have this problem. Given a 2D matrix, A, of any size [r,c]=size(A), I need to be able to write a function that finds a sub-section of the matrix A from the given inputs,
> > 1. i=scalar, the row where the sub section begins,
> > 2. j=scalar, the column where the sub section begins
> > 3. m= number of rows in the sub-section
> > 4. n= number of columns in the sub-section
> >
> > From this the function must output the subsection of the matrix, subA. Does anyone know where I can find a method to do this?
>
> On the getting started guide, in the matrix indexing guide and in the function guide (google them).
>
> BTW
>
> function OUT = foo(A, i, j, m, n)
> OUT = A(i:i+m, j:j+n)
> end
>
> Oleg



Thanks, I am having this problem though when I test the function.

with
A =
1 2 3 4 17
5 6 7 8 18
9 10 11 12 19
13 14 15 16 20

I would like to take out subA=(11, 12; 15, 16), so i=3, j=3, m=2, and n=2. I get the message index is out of bounds. Which I am assuming is because there is not 5 rows in my current A.
From: Oleg Komarov on 27 Feb 2010 13:07
"Samuel "
> "Oleg Komarov"
> > "Samuel "
> > > I am knew at writing matlab code, and I have this problem. Given a 2D matrix, A, of any size [r,c]=size(A), I need to be able to write a function that finds a sub-section of the matrix A from the given inputs,
> > > 1. i=scalar, the row where the sub section begins,
> > > 2. j=scalar, the column where the sub section begins
> > > 3. m= number of rows in the sub-section
> > > 4. n= number of columns in the sub-section
> > >
> > > From this the function must output the subsection of the matrix, subA. Does anyone know where I can find a method to do this?
> >
> > On the getting started guide, in the matrix indexing guide and in the function guide (google them).
> >
> > BTW
> >
> > function OUT = foo(A, i, j, m, n)
> > OUT = A(i:i+m, j:j+n)
> > end
> >
> > Oleg
>
>
>
> Thanks, I am having this problem though when I test the function.
>
> with
> A =
> 1 2 3 4 17
> 5 6 7 8 18
> 9 10 11 12 19
> 13 14 15 16 20
>
> I would like to take out subA=(11, 12; 15, 16), so i=3, j=3, m=2, and n=2. I get the message index is out of bounds. Which I am assuming is because there is not 5 rows in my current A.

In fact I'm bad at math:
> > OUT = A(i:i+m, j:j+n)
should be
OUT = A(i:i+m-1, j:j+n-1)

Oleg
From: Matt Dunham on 27 Feb 2010 13:49
"Samuel " <boo161620(a)yahoo.com> wrote in message <hmbll5$5h9$1(a)fred.mathworks.com>...
> Given a 2D matrix A, I need to write a function that displays a subsection of the matrix subA given the following inputs:
> A &#8211; A 2-D matrix. [r,c] = size(A) where r>=i+m and c>=j+n
> i &#8211; An integer scalar. A row number in A were the requested subsection begins.
> j &#8211; An integer scalar. A column number in A were the requested subsection
> begins.
> m &#8211; the number of rows in the subsection
> n &#8211; the number of column in the subsection
> Anybody have any ideas on where I can find more information on this or how I can write this code? Thanks for all your help!

subA = A(i:i+m-1, j:j+n-1)
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