Jamcleat

I do not claim any understanding of Nelder-Mead or anything like it, also called a downhill method of finding a minimum for a system of equations, which, if you keep up with these things, may be old news. But consider the possibility of the inverse, nearing the summit realizing that whatever your strategy and method, the climb has led you up the wrong peak. Or more to the point, in the valley, you cannot realize or see that the adjacent (or some very distant) valley is lower but not chosen because the initial solution set off in the wrong direction. The desired goal is now distant. Maybe in Step n, there could be a global check for other minima. Or maybe this accomplishes that trick.

While looking for information on “splines”, I stumbled over an interesting article in the Community Resources section of the Resources Tab for the Geology Department of Portland State University. The pdf file is a Self-guided tour of Portland, Oregon’s geology. This field trip provides an introduction to the geology of the Portland, Oregon, area. Five field trip stops, all accessible by public transportation and walks of easy to moderate difficulty, provide opportunities to see outcrops of Columbia River Basalt, Troutdale Formation, Boring volcanic field flow and vents, Portland Hills Silt, and a small landslide. I have never had a chance to visit the Northwest but might like to some day. This paper is an exciting chance to visit the neighborhood of Mt. St. Helens vicariously. And a way to spend a day or two out and about in the Portland area.

Also exciting is the description of the floods in the Portland area on 20-15 thousand years ago. Water levels 150m higher than current sea level! What short memories humans have. Maybe the geologists should buy the climatologists a cup of coffee and fill them in on life on earth.