Re: Reasonable integration speed? (24 hrs and counting)
- To: mathgroup at smc.vnet.net
- Subject: [mg68063] Re: Reasonable integration speed? (24 hrs and counting)
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Fri, 21 Jul 2006 17:35:59 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <e9nkvm$9vo$1@smc.vnet.net> <e9q97p$7tf$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
axlq wrote: > Update: Going on 48 hours now. I'm concerned that something is > hung, but I fear aborting the job if there's any chance it may > actually be progressing to a solution. I'm unfamiliar with what I > can expect in terms of Mathematica's speed of solving an integral. > Is this reasonable? Is there a setting somewhere that shows some > sort of progress indicator? > > -Alex > > In article <e9nkvm$9vo$1 at smc.vnet.net>, axlq <axlq at spamcop.net> wrote: >> I downloaded the trial version of Mathematica to see if it could >> solve a complex integral. After getting comfortable with solving >> simple integrals, I input my target problem: >> >> In[1]:= f[x] = Sqrt[a^2+(q-x)^2] >> >> In[2]:= Integrate[Cos[(2*n + 1)*Pi*x/d]* >> (Exp[-I*k*f[x]]/(4*Pi*f[x]^5)*((1 + I*k*f[x])*(2*f[x]^2 - 3*a^2) >> + (k*a*f[x])^2) * I*d/(2*Pi* w) + p), {x, -d/2, d/2}] >> >> Observations: >> >> 1. It's been sitting there for over 24 hours now. >> >> 2. Task Manager shows Mathematica's CPU usage at a constant 50%. >> >> 3. The "Kernel" pull-down menu has "Interrupt Evaluation" grayed out. >> I can abort it. >> >> 4. Mathematica won't solve any subsequent problem in another window >> (seems like the first one is occupying a queue). >> >> Earlier I tested some simple function-reference integrals (e.g. >> defining f[x] first and then integrating f[x]dx) and they worked. >> >> What sort of speed can I expect from this? Is 24 hours too long to >> solve a problem like this on a 2.6 GHz Windows XP platform with 1.25 >> GB RAM? Is Mathematica hung up on something? Is the fact that I'm >> using the trial version make any difference? Did I do something >> wrong? >> >> Thanks. >> -Alex > Hi Alex, I think you can abort the evaluation. Here is what I get on my system: f[x] = Sqrt[a^2 + (q - x)^2] Integrate[Cos[(2*n + 1)*Pi*(x/d)]*((Exp[(-I)*k*f[x]]/(4*Pi*f[x]^5))*((1 + I*k*f[x])*(2*f[x]^2 - 3*a^2) + (k*a*f[x])^2)*I*(d/(2*Pi*w)) + p), {x, -d/2, d/2}] displays after several minutes Integrate::"gener" : "Unable to check convergence. (I aborted the still running evaluation loop after that.) $Version "5.2 for Microsoft Windows (June 20, 2005)" Regards, Jean-Marc