FindRoot

*To*: mathgroup at yoda.physics.unc.edu*Subject*: FindRoot*From*: deutsch at bu-pub.bu.edu*Date*: Wed, 9 Sep 92 11:15:09 -0400

Hello, I provide Mathematica support for users here at Boston University. Recently a user has shown me a problem with FindRoot. Using Timing[s] where s := N[ FindRoot[{d1v==0,d2v==0},{p2,p20},{m3,m30}] ,15] and d1v := a function of p2 and m3 d2v := a function of p2 and m3 we observed that the time for solution was about 33 seconds which was reasonable given the complexity of d1v and d2v. However, when we repeated the same calculation we observed that the time more than doubled. Further attempts showed that the time continued to increase by a factor of 2. Are there any known problems with FindRoot that people are aware of? Does anyone have any suggestions as to what could be causing a problem of this type. Thank you, David Deutsch Information Technology Boston University deutsch at bu-it.bu.edu