What's New -  January, 2005



January 30, 2005:  We'll squeeze in one more update before the 1st month of the new year ends.   I have rewritten the divide procedure used in our Big Integers unit.  It's now between 10 and 10,000 times faster depending on the problem.   Here's a link to the Long Division test program that I wrote to compare old and new timing and results.  I also have a link there to the best paper available describing long division algorithms - essentially 23 pages written by a distinguished professor of Computer Science to describe what every 4th grader learns how to do.  And which I couldn't implement in code after several days of effort until I found Dr. Hansen's paper! 

The new Big Integer unit consolidates several versions that had evolved as I used it in other projects.  The  Big integers link above identifies the programs which have been recompiled and reposted using the new unit.    As I was in the middle of this, viewer Hans Klein sent me some interesting additions (and a couple of corrections) to the original Big Integers unit.   If the terms "ModPow", "InvMod", "Miller-Rabin", "Fermat's Little Theorem", "Carmichael numbers", or "RSA encryption" mean anything to you, you may want to check out the additions in the new version.   Thanks to Hans for the contributions and for your efforts in testing UBigIntsV2.     

January 23, 2005:  I finally posted the updates to DFF Play CD this afternoon.   This is a compilation of executable versions of 75 or so of our most popular programs.  The initial version was posted about 6 months ago.  Programs are categorized as Science, Math,  Two Player Games, Playable Puzzles, Solvers, and Tricks. 

This is version 2 has the following updated and added programs:

 I put in hyperlinks to the description pages in the above list , in case you are interested in  only one or two of the offerings.   The DFF Play CD files are downloadable as  DFF_Play_CD.zip, about 20 megabytes.   The files may be extracted to a disk folder  and run from that location or (as I originally intended) copied to a CD to hand out to the grandkids or anyone else you want to expose to math, science and the fun of learning!  

January 20, 2005:  Here is a MatchMerge  program which merges two text files in alpha text sequence and optionally saves the merged records in a new file.  Options are provided  to sort input files if they are not in sequence, and to eliminate duplicate records in the output file.  

January 15, 2005:  


I took a little time off to play with grandkids over the holidays, but apparently you viewers did not,  so I'm a little behind on fixes, never mind the new projects underway.    If your email is over a week old and hasn't been answered with at least an "I'll look into it", consider writing again.  

I did post Version 2 of my Cutlist program today.   The program plans the best way to cut a set of rectangular parts from a given set of supply material.   Today's fixes include:   

  • The European comma used for decimal point did not work properly when files were saved and restored.  I think it is working now, but I have a hard time testing it here.    

  • The material editing process has been improved, now  pops up a menu to let users modify, insert, delete, rotate, or duplicate parts.

  • Fixed some sort errors to make the solving process work better (i.e. more like I thought it should work). 

Thanks to Jasmin Bajric for the Cutlist bug reports and suggestions.