Dear Sir/Madam,
I am using the same approach in 'Inverse Modelling, Sensitivity and Monte Carlo Analysis in R Using Package FME' with different equations.  I have gone through this paper and is very useful to me specially how to use MCMC approach. I am doing similar thing by using your approach in your written R codes. 

I am finding it very difficult to continue from page 16. Kindly find my problem below. I will be very delighted if the list members can assist me.

>  plot(AIDScost(pars), xlab="time")
> AIDScost2 <- function(lpars){
+   AIDScost(c(exp(lpars), n = 900))
+ }
> Pars <- pars[1:10] * 2
>  Fit <- modFit(f = AIDScost2, p = log(Pars))
DLSODA-  Warning..Internal T (=R1) and H (=R2) are
      such that in the machine, T + H = T on the next step  
     (H = step size). Solver will continue anyway.
In above message, R = 
[1] 0 0
DINTDY-  T (=R1) illegal      
In above message, R = 
[1] 0.1
      T not in interval TCUR - HU (= R1) to TCUR (=R2)      
In above message, R = 
[1] 0 0
DINTDY-  T (=R1) illegal      
In above message, R = 
[1] 0.2
      T not in interval TCUR - HU (= R1) to TCUR (=R2)      
In above message, R = 
[1] 0 0
DLSODA-  Trouble in DINTDY.  ITASK = I1, TOUT = R1
In above message, I = 
[1] 1
In above message, R = 
[1] 0.2
Error in lsoda(y, times, func, parms, ...) : 
  illegal input detected before taking any integration steps - see written message

Thank you very much and to hope to hear list members. I will very appreciated for any help.

Regards,
Ofosuhene

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