stan wagon

306 reputation

	306 reputation	bio	website	stanwagon.com	visits	member for	1 year, 4 months
12 badges		location			seen	May 11 at 22:48

2 Comments

Jan 27	comment	Updating Wagon's FindAllCrossings2D[] function Not on hand. But this function is used many many times in the VisualDSolve project to find equilibrium points for two autonomous DEs and I must have found some difficult examples there. Now, it is possible as Mathematica changes internally that some of the problems disappear. Let me mention that this function was able to solve one of the "100 Digit Challenge" problems in optimizing a complicated function of 2 vbles by finding all of the critical points in the region, and there were well over 2000 of them.
Jan 26	comment	Updating Wagon's FindAllCrossings2D[] function I'm afraid I cannot remember exactly why I chose 97 and 103, but the reason is related to the effect that when things are too symmetric then there can be problems at the centers of symmetry. So it is best to add in a little asymmetry. Also I note that someone commented that some new Mathematica functions do some of these sorts of things.. but only for nice functions. If one had the Zeta function involved, say, then I do not believe their new algebraic ideas would work. Of course, since typical usages might be in DEs, finding equil. pts., it might be worth adding some cases to detect niceness.