Fix my code in R for a bass diffusion model

Hi, I would like someone to have a look over my code and fix it, so that I can calculate the correct parameters m, q, and p based on my real-life sales data. Here is the code: [login to view URL] <-c(0.376000,0.937000,4.416000,22.497000,39.409000,51.630000,54.828000,54.132000,50.315000,42.628000,35.165000,26.379000,14.377000) Sales <- diff([login to view URL]) sales <- [login to view URL][-1] sales2 <- sales*sales l <- length(Sales) # T <- 1:l # T = [1,2,3,4,5,6,7,8,9,10,11,12,13] # Bass GA bassf <- function(x,theta) theta[1] * ( ((theta[2]+theta[3])^2 / theta[2]) * exp(-(theta[2]+theta[3]) * T) ) /(1+(theta[3]/theta[2])*exp(-(theta[2]+theta[3])*x))^2 # f(t) fitnessL <- function(theta,x,y) -sum((y-bassf(x,theta))^2) library(GA) maxiter=500 GA3 <- ga(type="real-valued",fitness=fitnessL,x=T,y=Sales,lower=c(0,0,0),upper=c(9999999999,1,1),popSize=500,crossover=gareal_blxCrossover,maxiter=500,run=200,names=c("m","p","q")) summary(GA3) bassf <- function(x,theta) theta[1] * ( ((theta[2]+theta[3])^2 / theta[2]) * exp(-(theta[2]+theta[3])* x) ) /(1+(theta[3]/theta[2])*exp(-(theta[2]+theta[3])*x))^2 theta <- GA3@solution salesfit <- bassf(0:15,theta) salesfit Total_customer <-cumsum(salesfit) Total_customer plot(Total_customer,type="l") When running the code in R, I always get a value for M that is not possible based on the assumptions of the bass model. In the end I also want to plot the bass model function and show the development from year 2002 (start date of the sales data) to the end of the sales data 2014 and forecast until 2020. The data is in pcs sold millions. Please dont hesitate if you have further questions