I tried to estimate the SEIR MODEL parameter in R by using the following code .Unfortunately I couldn't get it because I get the following error :
"Error in names(parameters) <- c("beta_value", "gamma_value", "delta_value") : 'names' [3] has to be of the same length of the vector [2] .
Where am I wrong? The code used follow here.
R CODE :
seir_model = function (current_timepoint, state_values, parameters) { # create state variables (local variables) S = state_values [1] # susceptibles E = state_values [2] # exposed I = state_values [3] # infectious R = state_values [4] # recovered with ( as.list (parameters), # variable names within parameters can be used { # compute derivatives dS = (-beta_value * S * I) dE = (beta_value * S * I) - (delta_value * E) dI = (delta_value * E) - (gamma_value * I) dR = (gamma_value * I) # combine results results = c (dS, dE, dI, dR) list (results) } ) } RSS <- function(parameters) { names(parameters) <- c("beta_value", "gamma_value","delta_value") out <- ode(y = init, times = Day, func = seir_model, parms = parameters) fit <- out[, 3] sum((Infected - fit)^2) } library(deSolve) Opt_seir <- optim(c(0.5, 0.5), RSS, method = "L-BFGS-B", lower = c(0, 0), upper = c(1, 1) Opt_seir ``` 
