In fact I am not looking for an implementation but a method to update a vector iteratively when the value of an item of the vector depend partly on the already updated items and partly depend on the old items.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Nils Wagner Sent: Friday, February 16, 2007 9:19 AM To: Discussion of Numerical Python Subject: Re: [Numpy-discussion] Numpy and iterative procedures Nadav Horesh wrote: > At first glance it doesn't look hard to, at least, avoid looping over i, by replacing [i] by [:-2], [i+1] by [1:-1] and [i+2] by [2:]. But I might be wrong. Can you submit the piece of code with at least the most internal loop? > > Nadav. > I guess he is looking for an implementation of http://en.wikipedia.org/wiki/Successive_over-relaxation Nils > -----Original Message----- > From: [EMAIL PROTECTED] on behalf of Geoffrey Zhu > Sent: Thu 15-Feb-07 18:32 > To: Discussion of Numerical Python > Cc: > Subject: Re: [Numpy-discussion] Numpy and iterative procedures > > Thanks Chuck. > > I am trying to use Successive Over-relaxation to solve linear > equations defined by M*v=q. > > There are several goals: > > 1. Eventually (in production) I need it to be fast. > 2. I am playing with the guts of the algorithm for now, to see how it > works. that means i need some control for now. > 3. Even in production, there is a chance i'd like to have the ability > to tinker with the algorithm. > > > _____ > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Charles R > Harris > Sent: Thursday, February 15, 2007 10:11 AM > To: Discussion of Numerical Python > Subject: Re: [Numpy-discussion] Numpy and iterative procedures > > > > > > On 2/15/07, Geoffrey Zhu <[EMAIL PROTECTED]> wrote: > > Hi, > > I am new to numpy. I'd like to know if it is possible to code > efficient > iterative procedures with numpy. > > Specifically, I have the following problem. > > M is an N*N matrix. Q is a N*1 vector. V is an N*1 vector I am trying > to > find iteratively from the initial value V_0. The procedure is simply > to > calculate > > V_{n+1}[i]=3D1/M[I,i]*(q[i]- > (M[i,1]*v_{n+1}[1]+M[I,2]*v_{n+1}[2]+..+M[i,i-1]*v_{n+1}[i-1]) - > (M[I,i+1]*v_{n}[i+1]+M[I,i+2]*v_{n}[i+2]+..+M[I,N]*v_{n}[N])) > > I do not see that this is something that can esaily be vectorized, is > it? > > > I think it would be better if you stated what the actual problem is. Is > it a differential equation, for instance. That way we can determine what > the problem class is and what algorithms are available to solve it. > > Chuck > > > > > _______________________________________________________ > > The information in this email or in any file attached > hereto is intended only for the personal and confiden- > tial use of the individual or entity to which it is > addressed and may contain information that is propri- > etary and confidential. If you are not the intended > recipient of this message you are hereby notified that > any review, dissemination, distribution or copying of > this message is strictly prohibited. This communica- > tion is for information purposes only and should not > be regarded as an offer to sell or as a solicitation > of an offer to buy any financial product. Email trans- > mission cannot be guaranteed to be secure or error- > free. P6070214 > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Numpy-discussion mailing list > [email protected] > http://projects.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ Numpy-discussion mailing list [email protected] http://projects.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ Numpy-discussion mailing list [email protected] http://projects.scipy.org/mailman/listinfo/numpy-discussion
