plotting unconditional quantile graph using xtrifreg

[Scott Kang]

I have some difficulty in plotting unconditional quantile graph using xtrifreg

I found an example for rifreg here (http://faculty.arts.ubc.ca/nfortin/g...ifreg_coef1.do) but when I simply changed rifreg to xtrifreg, the code does not work.
I got an error "new variables cannot be uniquely named or already defined" at line " svmat double B, name(coef)".
If possible, I would like to also incorporate 95% CI (something like lfitci) on the graph

 set more off
save tempcf, replace emptyok  

forvalues q = 0.1(0.1)0.9 {
  use graph, clear
  quietly xtrifreg depvar lag_depvar indepvar time_dummy_list [aweight = matching_weights], quantile(`q') fe i(id)
  matrix B=e(b)
  svmat double B, name(coef)
  gen quant=`q'
  keep quant coef*
  keep if _n==1  
  append using tempcf 
  save tempcf, replace
 }
 

use tempcf, clear
sort quant
label var quant "Quantile"
*** choose the coefficient(s) that you want to graph, here coef2 is the coefficient of interest 
graph twoway (connected coef2 quant if quant>0.0 & quant<1.0  ) /*
   */, xlabel(0.0 0.2 0.4 0.6 0.8 1.0) title("indepvar") ytitle(" ") /*
   */  yline(0.0, lw(thin) lc(black)) saving(quantile_graph,replace)

graph export quantile_graph.wmf, replace