cobbler_squad
2010-Jan-29 21:44 UTC
[R] Help interpreting libarary(nnet) script output..URGENT
Hello, I am pretty new to R. I am working on neural network classifiers and I am feeding the nnet input from different regions of interest (fMRI data). The script that I am using is this: library (MASS) heap_lda <- data.frame(as.matrix(t(read.table(file="R_10_5runs_matrix9.txt")))*100000,syll = c(rep("heap",3),rep("hoop",3),rep("hop",3))) library(nnet) heap_nnet <- nnet(syll ~ ., data=heap_lda, size=12,iter=100,MaxNWts=10000) predict(heap_nnet,heap_lda,type = "class") table(predict(heap_nnet,heap_lda,type = "class"),heap_lda$syll) # do leave-one-out crossvalidation... heap_nnet.out<-NULL all = c(1:9) for(n in all){ heap_nnet <- nnet(syll ~ ., data=heap_lda[all != n,], CV =TRUE,size=12,iter=100,MaxNWts=10000) heap_nnet.out <- c(heap_nnet.out,predict(heap_nnet,heap_lda[all =n,],type = "class")) } table(heap_nnet.out,heap_lda$syll) ..the output I am receiving so far is fits in this structure..(this input is from 1 Region of interest file)> library(MASS) > heap_lda <- > data.frame(as.matrix(t(read.table(file="R_10_5runs_matrix9.txt")))*100000,syll > = c(rep("heap",3),rep("hoop",3),rep("hop",3))) > library(nnet) > heap_nnet <- nnet(syll ~ ., data=heap_lda, size=12,iter=100,MaxNWts=10000)# weights: 1719 initial value 10.469219 iter 10 value 0.057269 iter 20 value 0.000276 final value 0.000069 converged>> predict(heap_nnet,heap_lda,type = "class")[1] "heap" "heap" "heap" "hoop" "hoop" "hoop" "hop" "hop" "hop"> table(predict(heap_nnet,heap_lda,type = "class"),heap_lda$syll)heap hoop hop heap 3 0 0 hoop 0 3 0 hop 0 0 3> heap_nnet.out<-NULL > all = c(1:9) > > for(n in all){+ heap_nnet <- nnet(syll ~ ., data=heap_lda[all != n,], CV =TRUE,size=12,iter=100,MaxNWts=10000) + heap_nnet.out <- c(heap_nnet.out,predict(heap_nnet,heap_lda[all =n,],type = "class")) + } # weights: 1719 initial value 10.602879 iter 10 value 1.417881 iter 20 value 1.387453 iter 30 value 1.386296 final value 1.386294 converged # weights: 1719 initial value 11.055741 iter 10 value 0.096622 iter 20 value 0.000189 final value 0.000060 converged # weights: 1719 initial value 10.029384 iter 10 value 0.046705 final value 0.000063 converged # weights: 1719 initial value 10.997292 iter 10 value 0.011758 final value 0.000086 converged # weights: 1719 initial value 8.527452 iter 10 value 0.019332 final value 0.000060 converged # weights: 1719 initial value 7.470868 iter 10 value 0.016888 final value 0.000085 converged # weights: 1719 initial value 10.694363 iter 10 value 0.000740 iter 20 value 0.000310 final value 0.000057 converged # weights: 1719 initial value 13.334826 iter 10 value 0.032689 final value 0.000091 converged # weights: 1719 initial value 6.861594 iter 10 value 0.008161 final value 0.000081 converged> > table(heap_nnet.out,heap_lda$syll)heap_nnet.out heap hoop hop heap 2 1 1 hoop 0 1 0 hop 1 1 2 I am having trouble understanding how to interpret the output. is my intuition correct and we are comparing the heap_nnet <- nnet(syll ~ ., data=heap_lda, size=12,iter=100,MaxNWts=10000) [[[[[# weights: 1719 initial value 10.469219 iter 10 value 0.057269 iter 20 value 0.000276 final value 0.000069 converged]]]]] to the output of leave one out cross-validation? Is the better match the one that goes through least iterations and arrives at the closest approximation of the neural network classifier? General ideas/notes regarding this would be greatly appreciated. Also, which number of weights is best, the one with larger or the smaller number (given that our max_weights limit is set at 10000). I apologize for my lack of familiarity with this and the resulting stupid questions. Thanks. -- View this message in context: http://n4.nabble.com/Help-interpreting-libarary-nnet-script-output-URGENT-tp1431725p1431725.html Sent from the R help mailing list archive at Nabble.com.