Hello R Group I'm trying to apply the function interp.surface of the following data frame and it doesn't work x value is $Strike [1] 100 102 y Value is $Maturity [1] 25 35 z Value is ImplVol.100 ImplVol.102 1 0.419177 0.331999 2 0.264417 0.195447 I want to find the value of z for (x,y)=(101,30) Now I apply obj<- list( x=x, y=y, z=z) I define make.surface.grid( list(c(101,30),c(101,30)))-> loc (I want to interpolate for (x,y)=(101,30)) and interp.surface( obj, loc)-> look gives me an error. could you tell me where I'm wrong? Thanks -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._