# RegionPlot fails

Consider a function

f[x_,y_]:=NIntegrate[g[x,y,z],{z,1.1*x,3000}]


where g[x,y,z] is some function. The function f[x,y] is smooth and works perfectly when Plot it. However, when using

RegionPlot[f[10^x,10^y],{x,-3,62.5},{y,-20,-10}]


I got the message

Throw::nocatch: Uncaught Throw[-HolonomicDifferentialRootReduceDumpy[NIntegrateLevinRuleDumpx]+(HolonomicDifferentialRootReduceDumpy^\[Prime])[NIntegrateLevinRuleDumpx],NIntegrateLevinRuleDumpFastLookupHolonomicDifferentialEquation] returned to top level.


I tried to remove it by modifying

f[x_?NumericQ,y_?NumericQ]:=NIntegrate[g[x,y,z],{z,1.1*x,3000}]
RegionPlot[f[10^x,10^y],{x,-3,62.5},{y,-20,-10},"NumericalFunction"->False]


I got that 1.1*10^x is not a valid limit of integration.

What is the problem with this RegionPlot?

• Have you done Clear[f] before the second definition of f? You can check with ?f whether the first definition (the f[x_,y_]:= one) is still lingering around. – Roman May 14 '19 at 9:24
• Try `ContourPlot´ – Ulrich Neumann May 14 '19 at 9:50