Thread Subject:

can I use bsxfun for this?

Hi

I have

A=[a11 a12 a13;
     a11 a12 a13;
     a11 a12 a13]

and

b=[b1 b2 b3]

and would like to compute

[ a11-b1 a12-b2 a13-b3;
     a11-b1 a12-b2 a13-b3;
     a11-b1 a12-b2 a13-b3]

The actual number of columns of A and b is typically ~100
The number of columns of A und b can vary only together (i.e. 3 columns for A and 3 columns for b)

Thanks for any help.

Peter

On 12/27/2012 3:06 AM, Peter Schreiber wrote:
> Hi
>
> I have
>
> A=[a11 a12 a13;
> a11 a12 a13;
> a11 a12 a13]
>

Are you saying A has the same rows duplicated?
Becuase that is what you wrote above.


> and
>
> b=[b1 b2 b3]
>
> and would like to compute
>
> [ a11-b1 a12-b2 a13-b3;
> a11-b1 a12-b2 a13-b3;
> a11-b1 a12-b2 a13-b3]
>
> The actual number of columns of A and b is typically ~100
> The number of columns of A und b can vary only together
>(i.e. 3 columns for A and 3 columns for b)
>
> Thanks for any help.
>
> Peter
>

Peter:
Use
[rows columns] = size(A);
to get the number of rows in A, then use
B = repmat(B, [rows 1]);
to replicate B like this
b1 b2 b3
b1 b2 b3
b1 b2 b3
Then simply subtract
output = A-B;

In article <kbh320$1fp$1@newscl01ah.mathworks.com>,
 "Peter Schreiber" <schreiber.peter15@gmail.com> wrote:

> Hi
>
> I have
>
> A=[a11 a12 a13;
> a11 a12 a13;
> a11 a12 a13]
>
> and
>
> b=[b1 b2 b3]
>
> and would like to compute
>
> [ a11-b1 a12-b2 a13-b3;
> a11-b1 a12-b2 a13-b3;
> a11-b1 a12-b2 a13-b3]
>
> The actual number of columns of A and b is typically ~100
> The number of columns of A und b can vary only together (i.e. 3 columns for A
> and 3 columns for b)
>
> Thanks for any help.
>
> Peter

Yes,

bsxfun(@minus,A,b)

--
Doug Schwarz
dmschwarz&ieee,org
Make obvious changes to get real email address.