A formula for IRR

[Didier Lachieze]

(05-19-2015 12:49 PM)DrD Wrote:  Since L1 is a reserved variable, it always exists. It may be an empty list, but it shouldn't give an error when referenced. For example, set L1 to an empty list, L1:={}; then run this program:

Code:


EXPORT IRR()
BEGIN
  EDITLIST(L1,"Internal Rate of Return");  // test vals: {-123400, 36200, 54800, 48100} 
  RETURN solve(ΣLIST(MAKELIST((L1(I)/X^(I-1)),I,1,SIZE(L1))),X)-1;
END;

It seems to run ok. EDITLIST() has optional parameters, which may be useful, but the above code is a very handy program for the purpose.

It run ok from Home but not from CAS. If you replace "solve" by "Solve.SOLVE" (with an uppercase 'S') it works fine from both.