What's New - April, 2007
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April 30, 2007: A Large Files listing program was posted about 5 years ago has worked without error since then. Well there was an error that just was not recognized until Colin K found it the other day. The program lists the N largest files on a drive and worked fine unless a file exceeded the maximum value which could be contained in a 32 bit integer (about 2.1 Gigabytes). Sizes up to 64 bit integer capacity (9*1018)are now handled OK. That should be large enough for awhile J
April 29, 2007: There have been distractions from programming this month between spring time outside stuff, planning our vacation to Hawaii in June, and ferrying my wife around as she went through surgery for a herniated disk. Her doctor now has her on a walking program starting at a mile per day and working up to 3 miles per day in the next few weeks. I'll be walking with her, which should do us both good. And good preparation for climbing the 270 steps up to the Diamond Head overlook in Honolulu when we visit!
I did post the first bug fix today for the CuttingStock program posted early this month. Non-integer stock or part lengths were not handle properly. The Pascal code I adapted has integer dependency deeply embedded. Until I find a better solution, I now recognize decimal values and scale the lengths up by 10 or 100 to convert them to integers before solving. Then of course, divide all lengths by the same value before reporting results to users. (This works because, for example, the best away to cut parts of length 15 and 25 from stock of length 100 is has the same solution as cutting the same number of parts of length 1.5 and 2.5 from stock of length 10.)
April 13, 2007: Viewer Samuel from The Netherlands recently sent me the semitones for a Minor scale to add to the Major scale used in a BeepExDemo in our Delphi Techniques section. BeepExDemo was written originally to play notes on the PC speaker for all versions of Windows (the capability was missing from Win95, 98 and ME). I added the Minor scale as well as a Chromatic scale and, just for fun, a PlayTune procedure to play a predefined tune for you on your special day.
April 5, 2007: A small fix for Cutlist was posted today which should only affect those who used the manual method to layout pieces to be cut. Assume that a manual solution is saved and the program stopped. On next usage if the case is reloaded and an auto-solve solution is created, the manual solution might not have displayed correctly when reloaded. It should now.
April 1, 2007: Here is my crack at solving the Cutting Stock problem: how best to cut parts that only vary in one dimension, length or width, from stock that comes in lengths at least as long as the parts required. Those giant rolls of paper you've seen on "How It's Made" TV shows often need to be cut into narrower widths for specific applications. Manufacturers, distributors, or commercial users of wire, pipe, dimensional lumber, etc. often face a similar problem. And they lwant to do it in such a way that makes the best use of available stock. It made an interesting programming exercise and contains some interesting mathematics, at least conceptually within the grasp of us mere mortals. A sample solved problem is shown at right.