From: KAMAL ABAZA on
Hello Guys,
I'm Having a problem at integration a function on matlab the function is as follow :
Integral = ∫[ϕ(ω) e^(-jωE) dω] " integration from -∞ to +∞ "
Where: ϕ(ω)=∏[(1-j2ωλ(i))]^(-1) "multiplication"
λ is vector of eigen values KNOWN (the whole vector is available)
E is also known
ω is a variable unknown and I want to integrate on .
hope that the equations are clear enough
how can integrate this function numerically ???? !!!!
thanks in Advance
From: Roger Stafford on
"KAMAL ABAZA" <abaza_kamal(a)yahoo.com> wrote in message <hs46cc$ndc$1(a)fred.mathworks.com>...
> Hello Guys,
> I'm Having a problem at integration a function on matlab the function is as follow :
> Integral = &#8747;[&#981;(&#969;) e^(-j&#969;E) d&#969;] " integration from -&#8734; to +&#8734; "
> Where: &#981;(&#969;)=&#8719;[(1-j2&#969;&#955;(i))]^(-1) "multiplication"
> &#955; is vector of eigen values KNOWN (the whole vector is available)
> E is also known
> &#969; is a variable unknown and I want to integrate on .
> hope that the equations are clear enough
> how can integrate this function numerically ???? !!!!
> thanks in Advance
- - - - - - - -
Use 'quadgk', which accepts infinite limits of integration. You will need to write a function for your integrand which accepts vector arguments, and it will need to accept the known parameters E and vector lambda.

I assume that some of the eigenvalues in lambda are complex-valued in appropriate ways. Otherwise the function would not be integrable.

Roger Stafford
From: Bruno Luong on
"KAMAL ABAZA" <abaza_kamal(a)yahoo.com> wrote in message <hs46cc$ndc$1(a)fred.mathworks.com>...
> Hello Guys,
> I'm Having a problem at integration a function on matlab the function is as follow :
> Integral = &#8747;[&#981;(&#969;) e^(-j&#969;E) d&#969;] " integration from -&#8734; to +&#8734; "
> Where: &#981;(&#969;)=&#8719;[(1-j2&#969;&#955;(i))]^(-1) "multiplication"
> &#955; is vector of eigen values KNOWN (the whole vector is available)
> E is also known
> &#969; is a variable unknown and I want to integrate on .
> hope that the equations are clear enough
> how can integrate this function numerically ???? !!!!

It seems like you can use Residue Theorem to compute such thing almost by hand.

Bruno
From: Roger Stafford on
"Bruno Luong" <b.luong(a)fogale.findmycountry> wrote in message <hs4kef$c9p$1(a)fred.mathworks.com>...
> It seems like you can use Residue Theorem to compute such thing almost by hand.
>
> Bruno

I agree, Bruno!

Roger Stafford
From: Patricia Rosales on
Thank you for your help.

Best wishes

"John D'Errico" <woodchips(a)rochester.rr.com> wrote in message <hs12j9$7h6$1(a)fred.mathworks.com>...
> "Patricia Rosales" <proslop(a)oc.mde.es> wrote in message <hrmnul$qv9$1(a)fred.mathworks.com>...
> > Hello,
> >
> > I have an image that is a matrix of 508x640 values of a physical magnitude(radiance).
> > In order to obtain the whole radiance of the image, i want to integrate all the values in the whole image. But this means to perform an integration where the integrand is a set of values, not a function. Could anyone to help me with this?
> >
> > Thank you!
>
> Let me try again. trapz is the tool to integrate an array
> or vector of numbers.
>
> Perhaps you are confused in that trapz did not give you
> a SINGLE number.
>
> Perhaps you do not understand that an integration is
> applied to a SINGLE variable at once. Since an array
> (an image) is a two dimensional thing, you will need
> to do two integrations.
>
> How do you do two integrations, one on each variable?
>
> Call trapz twice!
>
> If this is not the answer to your problem, then you need
> to seriously learn to explain your problems better and
> more clearly. Learn to explain problems in mathematics
> by using mathematics.
>
> John