Sequential Sum of Squares Code

Hello,

I am new to r and programming in general. I cant figure out why the following code is not working.

###############################################################################################
#Sequentail Sum of Squares--------------------------------------------------------------------#
###############################################################################################

SS.seq = function(y,predictor,all.predictors)
{

SS = vector(,length=all.dim(predictors)[2])

mean = mean(y)
yhat = lm(y~all.predictors[,1])

sum.RSS.full = 0 #initialize sum#
sum.RSS.red = 0 #initialize sum#
sum.SSyy = 0 #initialize sum$

for (i in 1:length(y)) #calculate RSS#
{

sum.RSS.full = (yhat.full[i]-y[i])^2 + sum.RSS.full
sum.RSS.red = (yhat.red[i]-y[i])^2 + sum.RSS.red
sum.SSyy = (y[i]-mean)^2 + sum.SSyy

}

SS.seq = sum.RSS.red-sum.RSS.full
SSyy = sum.SSyy
SS = 100*(SS.seq/SSyy)

cat("SS1: ",SS.seq) #print result#
cat("\n")

for (i in 2:dim(predictors)[2])
{

yhat.full = lm(y~all.predictors[,i])
yhat.red = lm(y~subset(all.predictors,c(1:i-1,i+1:dim(predictors)[2]))

sum.RSS.full = 0 #initialize sum#
sum.RSS.red = 0 #initialize sum#
sum.SSyy = 0 #initialize sum#

for (j in 1:length(y)) #calculate RSS#
{

sum.RSS.full = (yhat.full[j]-y[j])^2 + sum.RSS.full
sum.RSS.red = (yhat.red[j]-y[j])^2 + sum.RSS.red
sum.SSyy = (y[j]-mean)^2 + sum.SSyy
}

SS.seq[i] = sum.RSS.red-sum.RSS.full
SSyy[i] = sum.SSyy
SS[i] = 100*(SS.seq/SSyy)

}

cat("Sequential Sum of Sqaures: ",SS)

}

###############################################################################################
#Sequentail Sum of Squares--------------------------------------------------------------------#
###############################################################################################

I am not sure if my loops are correct.

Any help would be great.

Thansk