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                | Anne6 | 
                Posted - 04/29/2013 : 05:43:32 AM  Origin Ver. and Service Release (Select Help-->About Origin): 8 Operating System: windows 7
  Hello everyone, 
  I'm not familiar with the user defined fitting functions in Origin 8 and I a trying to implement one but don't succeed so far.. 
  Here is the function :  independent variable : x dependent variable : y parameters names : as,ar,b,f,a,c
  loop(int n,0,c-1){f = f + ((a*x)^n * exp(-a*x))/n!);}; y = f*exp(-as*x) + (1,0-f)*exp(-ar*x - b*x^2);
  I selected Origin C as function form. If I try to compile, I get an error message telling that something is not declared inside the loop.  What should I do to get it work ? 
  Thanks a lot ! 
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                | greg | 
                Posted - 05/03/2013 : 4:34:29 PM  loop is not found in Origin C and neither is factorial (n!) Try this
  for(int n = 0 ; n <= c-1 ; n++) { 	val = n; 	for( factorial = 1 ; val > 1 ; val -- ) factorial *= val; 	f = f + ((a*x)^n * exp(-a*x))/factorial); } y = f*exp(-as*x) + (1,0-f)*exp(-ar*x - b*x^2);
  Note that c must be an integer less than 171. | 
               
             
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