text: #include <R.h>
   #include <math.h>
   void errfn_petab_deriv_2hp97lty ( double * x, double * y, double * p, int * n, int * k, int * l ) {
   for(int i = 0; i< *n; i++) {
   y[16+i**l] = 1.0 ;
  y[21+i**l] = 1.0 ;
  y[26+i**l] = 1.0 ;
  y[31+i**l] = 1.0 ; 
  }
  }