Very cool! Re bolts: I used to work in the clothing industry. "Bolts" of cloth go from nominally 42 inches wide (British wools), to nominally 60 inches wide (American wools). In reality, the usable cloth is around 4-6 inches smaller. Wool is notorious for changing its "size" with temperature and humidity, so clothing manufacturers often put it through a standardization process when it is received which wets it and dries it. The entire bolt is unrolled, goes through the machine, and is re-rolled, during which time the width is continuously recorded & stored in a database for that bolt. I worked on a computer program to virtually "lay out" ("marking") the pattern pieces on the wool to figure out how much cloth a suit would require. Laying out multiple suits at the same time is typically more efficient in terms of fitting the parts together better, but it is more complex to find all the parts after the cutting process and put them together. This process is a 2-D knapsack problem, and is obviously very difficult. Additional constraints involve "one way materials", matching stripes, matching plaids, non-symmetrical stripes, non-symmetrical plaids. It was lots of fun. At 11:59 PM 10/31/03 -0800, R. William Gosper wrote:
My unit-conversion challenges prompted me to write a long-planned Macsyma package. (Macsyma comes with a units package that leaves much to be desired and brings much to be undesired.)
To further show off my package, (c151) uconv(hectare,meter*yard)
12500000 meter yard (d151) ------------------- 1143
a crazy unit of area that was claimed to be used in Japanese cloth trade, due to cutting off metric lengths from bolts woven with the old British loom width. However, Rowlett's definition of "bolt" lists different widths for different fabrics, none of which is a yard.