diff --git a/R/cnbinom.pars_function.R b/R/cnbinom.pars_function.R
index a347fbc..22432a1 100644
--- a/R/cnbinom.pars_function.R
+++ b/R/cnbinom.pars_function.R
@@ -3,7 +3,7 @@ library(stringr)
 # cnbinom.pars is a function that outputs mu and r from univariate censored table input 
 # assume negative binomial 
 
-cnbinom.pars<-function (censoredtable){
+cnbinom.pars<-function (censoredtable, mu0 = 100, r0 = 100, warn = -1, ...){
   
   
   # make probabilities if not already
@@ -283,11 +283,12 @@ findtypeofcensoring_univariatetable<-function (univariatefreqtable){
 
   # optimize mu and r in loglikelihood_univariatecase
   # hide warnings... 
-  options(warn=-1)
+    options(warn = warn)
+    
   fixdata_univariatecase_output=fixdata_univariatecase(censoredtable)
-  op<- optim(par=c(100,100),
+  op<- optim(par=c(mu0, r0),
              fn =loglikelihood_univariatecase, 
-             fixdata_univariatecase_output=fixdata_univariatecase_output)
+             fixdata_univariatecase_output=fixdata_univariatecase_output, ...)
   final<-op$par
   mu = final[1]
   r = final[2]
diff --git a/README.md b/README.md
index c955dcc..6c77659 100644
--- a/README.md
+++ b/README.md
@@ -23,13 +23,16 @@ library(revengc)
 ## Usage
 `cnbinom.pars()` has the following format 
 ```
-cnbinom.pars(censoredtable)
+cnbinom.pars(censoredtable, mu0 = 100, r0 = 100, warn = -1, ...)
 ``` 
 
 where a description of the argument directly below 
 
 * **censoredtable** - A frequency table (censored and/or uncensored).  A data.frame and matrix are acceptable classes.  See Table format section below.
-
+* **mu0, r0** starting values for `mu` and `r` used by optim.
+* **warn** - Value used for `options(warn)` during `optim()` fitting. 
+  `-1` suppresses warnings
+* **...** - Additional arguments to be passed to `optim()`
 
 `rec()` has the following format where a description of each argument is found below