Bug: HP Prime can't do Log's

[Werner]

(12-15-2015 07:43 AM)davimle Wrote:  Now for the very small differences: 1 + 1E-13 - 1
[Note: I debated about whether I should adjust this to 1E-14 for the calculators that are using 15 digits, however, it seems their threshold is also 1E-13.]

Code:

  Prime (Home):   0
  Prime (CAS):    9.94759830064E-14
  EL-W516X:       0
  iOS calc:       1E-13
  pCalc app:      9.9999977916E-14

So it would seem that Prime in regular mode employs some of the same tricks as attributed to TI in the paper. CAS mode is again, just strange (why can't it get the precise answer?).

Prime regular carries only 12 digits for intermediate results, so 1. + 1e-13 equals 1. No fiddling here (or anywhere, on HP calcs!)
Prime CAS uses binary floating point, I seem to remember from Bernard's posts a while ago. And 0.99 and 0.01 are not exactly representable in binary, hence the small errors.

Cheers, Werner