RE: Speeding up ReadList[]?
- To: mathgroup@smc.vnet.net
- Subject: [mg12028] RE: [mg12020] Speeding up ReadList[]?
- From: "jmt" <jmthomas@cybercable.tm.fr>
- Date: Fri, 24 Apr 1998 01:52:02 -0400
You can down load a copy of a package I wrote to read Excel files: ftp://tea.fr.eu.org The directory Mathematica/Spreadsheet contains a .m file and a .nb file for documentation (in English). Hope this helps, **************************************** Jean-Marie THOMAS Conseil et Audit en Inginierie de Calcul Strasbourg, France **************************************** -----Original Message----- From: John Sidles [mailto:sidles@u.washington.edu] To: mathgroup@smc.vnet.net Subject: [mg12028] [mg12020] Speeding up ReadList[]? I use Mathematica to process Excel spreadsheets containing large arrays ({500,500}) of ASCII-coded floats. To read in the lists, I use the Mathematica function ReadList[stream, Number, RecordLists->True] Everything works fine, except that as each new array, is read and processed, ReadList[] gets slower and s l o w e r and s...l...o...w...e...r. The first ReadList[] takes only 40 seconds, while the second ReadList[] can take 400 seconds or longer, and I don't even know how long the third ReadList[] takes. Each file is processed independently, and no large arrays are retained in memory (they are stored as local variables inside Module[] blocks). VIrtual memory is not used, and both the Kernel and the Notebook retain plenty of unallocated memory. Each file does generate a large Graphics[] object, but surprisingly, Mathematica does not slow down while computing each graphic. Thus, ReadList[] is the only function evidencing a slowdown. Neither the MathSource nor the FAQ seem to address this problem. Has anyone else run into this slowdown, and how can it be avoided? Thanks ... JAS