Ray and other contributors, Might some of these Excel scripts/methods be candidates for posting to the SI web site for general distribution? I understand that many may be company confidential. regards, jon -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Ray Anderson Sent: Thursday, September 30, 2004 8:47 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Excel:an excellent tool for SI? yu.yanfeng@xxxxxxxxxx wrote: >All Gurus, > >Although Microsoft's Excel is applicable to some of SI's calculation, but >It's not a pratical method for recursive calculations, because it's >running time is very long. Ofcourse, I believe you can writes own codes >for SI analysis. As we known, lot of engineers often write Mathlab codes >to do thier analysis. But Do you consider whether the running speed is >comaparable to those commercial tools which dedicated to SI? Writing codes >and writing speedy codes are different things. > >Ultraeditor will replace 10,000,000 instances of a character in seconds. >Notepad also can do same things but in hours, Wordpad in less hours, >Winword in ten minutes. > >Yanfeng Yu > > Whether a particular tool is practical or not depends on your application and requirements. In one application where I utilized the recursive calculation capabilities of Excel to determine the voltage drop from the VRM to every node on the PCB (in this case, 400 nodes, the result of 20x20 griding), the approx.10,000 recursive iterations it took to converge required a bit less than 30 seconds. This was certainly acceptable to me. Had I elected to use much more dense griddling and needed to evaluate the voltage at say 10,000 nodes, then perhaps Excel might not have been the right tool. I agree that tools written in Matlab, Mathcad, Excel or other more or less general purpose tools will usually exhibit performance much less than special purpose tools that have been painstakingly optimized for execution speed and efficiency. However, depending on circumstances, the reduced efficiency and resulting longer run times might be just fine. Some tasks require special purpose industrial strength tools to achieve usable execution time and accuracy. Some tasks can be solved less expensively at the expense of run time and/or accuracy with lesser tools. It is just another case of using engineering judgment to do a cost/performance trade off. When you elect to use a well developed commercial tool you can gain at least several benefits: the expertise of the tool developers, better accuracy, faster execution time, ease of use. A Masserati and a '64 VW bug will both get you from point A to point B, it's up to the user to determine which one is appropriate to use for any particular trip.... Having more than 1 or 2 tools in your toolbox gives one the flexibility to choose which one is best a particular task at a particular time. Some tasks might requires one particular tool while other tasks might be accomplished with one of several available tools. -Ray ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.762 / Virus Database: 510 - Release Date: 9/13/2004 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.762 / Virus Database: 510 - Release Date: 9/13/2004 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu