Prev: Hex to IEEE single precision conversion
Next: Correlation changes over time programming question
From: TideMan on 16 Jul 2010 17:29
On Jul 17, 9:18 am, "Sean Douglas" <seanjdoug...(a)hotmail.com> wrote:
> dpb <n...(a)non.net> wrote in message <i1qhmc$36...(a)news.eternal-september.org>...
> > Sean Douglas wrote:
> > > i want to look at a matab built in function to understand it better. the
> > > particular function is:    qr(x,0)  , so i think there must be a built
> > > in function called qr.
>
> > > can someone tell me how to pull up this build in mfile so i can look at
> > > the code that operates this built in function?
>
> > type qr.m
>
> > What you'll see, of course, is the help header including the note at the
> > bottom that QR is a built-in function.  That means it is compiled code
> > and the source is not available as for functions implemented as m-files..
>
> it thought i should be able to see the built in function  because i know there have been times when i screw up code from say maybe not defining enough variables. when this happens red lettering shows up in the command window showing what built in function has the error. When this happens i can click on the red letters which indicate the built in function and an mfile will come up that i can look at.    
>
>
>
> > So, you'll have to recast your wishes to be in consonance w/ reality in
> > this particular instances... :)
>
> > --
>
> it thought i should be able to see the built in function  because i know there have been times when i screw up code from say maybe not defining enough variables. when this happens red lettering shows up in the command window showing what built in function has the error. When this happens i can click on the red letters which indicate the built in function and an mfile will come up that i can look at.    
>
>

Instead of continuing to bash your head against a wall, may I suggest
a different strategy?
You want to see how QR works, so why not type:
orthogonal-triangular decomposition
into Google and sit back and watch what happens?
From: Sean Douglas on 16 Jul 2010 18:16
TideMan <mulgor(a)gmail.com> wrote in message <7e523c54-e493-4d6d-8704-b5bd6b18d1d3(a)w37g2000prc.googlegroups.com>...
> On Jul 17, 9:18 am, "Sean Douglas" <seanjdoug...(a)hotmail.com> wrote:
> > dpb <n...(a)non.net> wrote in message <i1qhmc$36...(a)news.eternal-september.org>...
> > > Sean Douglas wrote:
> > > > i want to look at a matab built in function to understand it better. the
> > > > particular function is:    qr(x,0)  , so i think there must be a built
> > > > in function called qr.
> >
> > > > can someone tell me how to pull up this build in mfile so i can look at
> > > > the code that operates this built in function?
> >
> > > type qr.m
> >
> > > What you'll see, of course, is the help header including the note at the
> > > bottom that QR is a built-in function.  That means it is compiled code
> > > and the source is not available as for functions implemented as m-files.
> >
> > it thought i should be able to see the built in function  because i know there have been times when i screw up code from say maybe not defining enough variables. when this happens red lettering shows up in the command window showing what built in function has the error. When this happens i can click on the red letters which indicate the built in function and an mfile will come up that i can look at.    
> >
> >
> >
> > > So, you'll have to recast your wishes to be in consonance w/ reality in
> > > this particular instances... :)
> >
> > > --
> >
> > it thought i should be able to see the built in function  because i know there have been times when i screw up code from say maybe not defining enough variables. when this happens red lettering shows up in the command window showing what built in function has the error. When this happens i can click on the red letters which indicate the built in function and an mfile will come up that i can look at.    
> >
> >
>
> Instead of continuing to bash your head against a wall, may I suggest
> a different strategy?
> You want to see how QR works, so why not type:
> orthogonal-triangular decomposition
> into Google and sit back and watch what happens?


all the examples i see in for qr factorization are for matrixes of at least 2 columns. Does anyone know what to do if i am doing qr factorization on a one column matix? should i create a 2 column matrix and just make the second colomn alll zeros?
thanks for any help
From: Bruno Luong on 17 Jul 2010 03:01
"Sean Douglas" <seanjdouglas(a)hotmail.com> wrote in message <i1qln4$lhl$1(a)fred.mathworks.com>...
>
> all the examples i see in for qr factorization are for matrixes of at least 2 columns. Does anyone know what to do if i am doing qr factorization on a one column matix? should i create a 2 column matrix and just make the second colomn alll zeros?
> thanks for any help

Unbelievable question showing you do not really understand QR yet want to use it. Obviously the goal you want to achieve is not clear in your mind. Sorry for the hard words but I think it's better if someone (me) spells it out.

Bruno
From: Jan Simon on 17 Jul 2010 07:12
Dear Sean,

> all the examples i see in for qr factorization are for matrixes of at least 2 columns. Does anyone know what to do if i am doing qr factorization on a one column matix? should i create a 2 column matrix and just make the second colomn alll zeros?

If all examples you found in the world wide web concern at least 2 columns, this is a strong evidence, that 1-column-QR is not needed by anybody else.
Why?

Look in the documentation of QR in Matlab or at wikipedia and think of the possibilities to create an right-upper-triangular matrix with 1 column. The best solution is of course to let R equal A, which has the magic side-effect, that Q is the identity matrix.

I'm really sure, that seeing the QR implementation used as built-in Matlab function will *not* help to answer your questions.

Kind regards, Jan
From: dpb on 17 Jul 2010 10:25
Jan Simon wrote:
....

> the possibilities to create an right-upper-triangular matrix with 1
> column. The best solution is of course to let R equal A, ...

which is also a somewhat peculiar shape for an rut-matrix (excepting one
special case, of course)... :)

--
First  |  Prev  |  Next  |  Last
Pages: 1 2 3
Prev: Hex to IEEE single precision conversion
Next: Correlation changes over time programming question