SFEerrorsurf (R 2.13.1)
plots error surface Q(w)=1/2sum(y-o)^2, using sigmoid activation y=1./(1+exp(-p*x))
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Fri, June 15 2012 by Dedy Dwi Prastyo
Description: -
Description: -
rm(list=ls(all=TRUE)) graphics.off() require(lattice) x = matrix(c(0,1,0,1,0,0,1,1),ncol=2) y = cbind(0,1,1,1) # boolean function OR bias = 0.5 p = 5 k = 60 s = -1 b = 0.05 q = seq(s,by=b,length.out =k) q = as.matrix(q) w = matrix(1,k^2,2) for(i in 1:k) { for(j in 1:k) { w[i+(j-1)*k,1] = q[i] w[i+(j-1)*k,2] = q[j] } } w4 = matrix(0,nrow=nrow(w),1) i = 1 while(i<=nrow(x)) { w1 = x[i,1]*w[,1]+x[i,2]*w[,2]-bias w2 = 1/(1+exp(-p*w1)) w3 = (y[i]-w2)^2 w4 = w4+w3 i=i+1 } aa = cbind(w,w4) w4res = matrix(w4,60,byrow=T) # reshape w4 meshgrid = function(a,b){ # define meshfunction list( x=outer(b*0,a,FUN="+"), y=outer(b,a*0,FUN="+") )} a = meshgrid(seq(s,by=b,length.out =k),seq(s,by=b,length.out =k)) # compute meshgrid wireframe(w4res~a$x+a$y,main="Error Surface Q(w)",screen = list(z = -70, x = -70, y = 3), aspect = c(1,1),scales=list(arrows=FALSE, x=list(labels=seq(-1,2,0.5)),y=list(labels=seq(-1,2,0.5)),z=list(labels=seq(0,3,0.5))), xlab="X", ylab="Y", zlab="Q(w)") w4 = matrix(0,nrow=nrow(w),1) i = 1 while(i<=nrow(x)){ w1 = x[i,1]*w[,1]+x[i,2]*w[,2]-bias w2 = w1/abs(w1) w2=cbind(w2) w2[w2==-1]=0 # replace -1 with 0 w2[is.nan(w2)==TRUE]=0 # replace NaN with 0 w3 = (y[i]-w2)^2 w4 = w4+w3 i=i+1 } w4res=matrix(w4,60,60) # reshape dev.new() wireframe(w4res~a$x+a$y, main="Error Surface Q(w)",screen = list(z = -70, x = -70, y = 3), aspect = c(1,1),scales=list(arrows=FALSE, x=list(labels=seq(-1,2,0.5)),y=list(labels=seq(-1,2,0.5)),z=list(labels=seq(0,3,0.5))), xlab="X", ylab="Y", zlab="Q(w)")