Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Replies: 7   Last Post: Apr 22, 2013 10:39 AM

 Messages: [ Previous | Next ]
 Steven Lord Posts: 18,038 Registered: 12/7/04
Posted: Apr 22, 2013 10:39 AM

"A " <skgt046@ucl.ac.uk> wrote in message
news:kkvhcv\$30r\$1@newscl01ah.mathworks.com...
> "Torsten" wrote in message <kk8or3\$4eo\$1@newscl01ah.mathworks.com>...
>> "Bruno Luong" <b.luong@fogale.findmycountry> wrote in message
>> <kk8o6f\$2r5\$1@newscl01ah.mathworks.com>...

>> > "A " <skgt046@ucl.ac.uk> wrote in message
>> > <kk8njm\$1a4\$1@newscl01ah.mathworks.com>...
>> >

>> > >
>> > > It did not work with me. It says that there is no matching between
>> > > the inner matrix!

>> >
>> > I bet there is no matching between what you post and what you test on
>> >
>> > Bruno

>>
>> Looks as if the OP's vectors are row vector. not column vectors.
>> Otherwise I don't see why X_orth*Y'
>> should give a scalar.
>>
>> Best wishes
>> Torsten.

>
> It works with me !!
>
> but I thought the result Should be zero ?

In an ideal world, yes it should be exactly zero. The real world is not
ideal. In the real world, it should be close to zero for some definition of
close.

> Is there another way or making X'*Y=0

Going to arbitrary precision arithmetic calculations using Symbolic Math
Toolbox may do what you're asking for, but you will suffer a performance hit
for doing so. Better ...

> Since I am entering these in a program that evaluate orthogonality and
> should find it equals 0

modify the program that evaluates the orthogonality to count results that
are "close enough" to 0 as orthogonal. The definition of "close enough" is
up to you.

--
Steve Lord
slord@mathworks.com
http://www.mathworks.com

Date Subject Author
4/11/13 A
4/12/13 Bruno Luong
4/12/13 A
4/12/13 Bruno Luong
4/12/13 Torsten
4/20/13 A
4/21/13 Bruno Luong
4/22/13 Steven Lord