Re: Direction Fields

*To*: mathgroup at smc.vnet.net*Subject*: [mg2088] Re: Direction Fields*From*: kluge at seuss.cc.utexas.edu ()*Date*: Fri, 29 Sep 1995 01:13:49 -0400*Organization*: Computation Center, University of Texas

nprive at mbhs.edu (Nikki Prive ) asks: in an attempt to create direction fields ... My textbook says I must first type ">>Graphics`PlotField` Your problem here is in part do to an incorrect Mathematica syntax. The syntax to read in this package is "<<Graphics`PlotField`", with <<, not >>. This produces the error message: Syntax::sntxf: ">>Graphics`PlotField" cannot be followed by "`". However, this still leaves your first problem. The first error message is the result of reading in the package (so I think you had the right syntax that time), which defines the function PlotVectorField. Somehow this function has already been defined to Mathematica. Try to reload the Graphics`PlotField` package, with the correct syntax, as the FIRST thing you do when you start Mathematica. If the Warning: Symbol PlotVectorField appears in multiple contexts persists, then it is likely that you are preloading the PlotField package, i.e. it is loaded automatically for you when Mathematica starts. If this is the case then you can use PlotField without having to load any packages. Hope this helps, A. Kluge The University of Texas at Austin