Contours for negative and positive in ContourPlot

*To*: mathgroup at smc.vnet.net*Subject*: [mg123145] Contours for negative and positive in ContourPlot*From*: Chris Young <cy56 at comcast.net>*Date*: Thu, 24 Nov 2011 06:58:54 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

I got the following to plot different styles of contours for negative and positive values, by using RegionPlot to make separate plots. I suppose I could use a list of contours with style directives included. This would be more cumbersome coding, but the current version is really slow to respond. Chris Young cy56 at comcast.net Manipulate[ Row[ { Show[ ContourPlot[ Sin[x y], {x, x0, x1}, {y, y0, y1}, ColorFunction -> (Hue[#, sat, bri] &), ContourStyle -> {Directive[Green, Dotted, AbsoluteThickness[thick], Opacity[opac]]}, RegionFunction -> Function[{x, y}, Sin[x y] > 0] ], ContourPlot[ Sin[x y], {x, x0, x1}, {y, y0, y1}, ColorFunction -> (Hue[#, sat, bri] &), ContourStyle -> {Directive[Red, Dotted, AbsoluteThickness[thick], Opacity[opac]]}, RegionFunction -> Function[{x, y}, Sin[x y] < 0] ] ], ContourPlot3D[ Sin[x y] == z, {x, x0, x1}, {y, y0, y1}, {z, -1, 1}, BoxRatios -> {x1 - x0, y1 - y0, 2}, MeshFunctions -> {#3 &}, Lighting -> "Neutral", ColorFunction -> (Hue[#3, sat, bri] &) ] } ], {{x0, -4}, -4, 4}, {{x1, 4}, -4, 4}, {{y0, -4}, -4, 4}, {{y1, 4}, -4, 4}, {{thick, 1}, 0.1, 4, 0.1}, {{n, 4}, 0, 35, 1}, {{sat, 0.5}, 0, 1}, {{bri, 0.5}, 0, 1}, {{opac, 0.5}, 0, 1} ]