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Avoiding computational underflow when using Plot3D

bob frenkel

bob frenkel, Retired

Posted 6 months ago

I get a surface when using Plot3d that is incomplete. The error message says that some numbers could not be handled because of underflow. How can I avoid underflow and get a complete surface? Thank you. Bob Frenkel frenkelfamily@hotmail,com Attachments: Rev29Oct.nb

POSTED BY: bob frenkel

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Gareth Russell

Gareth Russell, New Jersey Institute of Technology

Posted 6 months ago

Even simpler: just add the option "PlotPoints->101" to your original code.

POSTED BY: Gareth Russell

Michael Rogers

Michael Rogers, Emory University

Posted 6 months ago

If you want a nicer plot, try scaling: Plot3D[(1/(2Pi))(1/0.2)(1/0.5)(1/ 6)(Exp[-(0.5/0.04)(x + 2.0)^2]Exp[-(0.5/0.25)(y - 1.2)^2] + Exp[-(0.5/0.04)(x + 0.5)^2]Exp[-(0.5/0.25)(y - 1.5)^2] + Exp[-(0.5/0.04)(x - 1.4)^2]Exp[-(0.5/0.25)(y - 2.9)^2] + Exp[-(0.5/0.04)(x - 3.1)^2]Exp[-(0.5/0.25)(y - 3.1)^2] + Exp[-(0.5/0.04)(x - 4.3)^2]Exp[-(0.5/0.25)(y - 3.3)^2] + Exp[-(0.5/0.04)(x - 5.7)^2] Exp[-(0.5/0.25)*(y - 4.2)^2]), {x, -4, 8}, {y, -4, 8}, PlotRange -> {0, 0.5}, ScalingFunctions -> {10^4 # &, #/10^4 &}]

If you want a nicer plot, try scaling:

Plot3D[(1/(2*Pi))*(1/0.2)*(1/0.5)*(1/
    6)*(Exp[-(0.5/0.04)*(x + 2.0)^2]*Exp[-(0.5/0.25)*(y - 1.2)^2] + 
    Exp[-(0.5/0.04)*(x + 0.5)^2]*Exp[-(0.5/0.25)*(y - 1.5)^2] + 
    Exp[-(0.5/0.04)*(x - 1.4)^2]*Exp[-(0.5/0.25)*(y - 2.9)^2] + 
    Exp[-(0.5/0.04)*(x - 3.1)^2]*Exp[-(0.5/0.25)*(y - 3.1)^2] + 
    Exp[-(0.5/0.04)*(x - 4.3)^2]*Exp[-(0.5/0.25)*(y - 3.3)^2] + 
    Exp[-(0.5/0.04)*(x - 5.7)^2]*
     Exp[-(0.5/0.25)*(y - 4.2)^2]), {x, -4, 8}, {y, -4, 8},
 PlotRange -> {0, 0.5}, ScalingFunctions -> {10^4 # &, #/10^4 &}]

POSTED BY: Michael Rogers