Torture tests: what do they mean?

[DavidM]

(05-13-2014 10:58 PM)jebem Wrote:  For example, the tan(355/226) has an ideal result of -7497258.185...
It gives me the following results (in Radian mode) for these models:

HP-Prime: -7497089.06508
HP-50G: -7497089.06508
Casio FX-991DE PLUS: -7497258.44
WP-34S: -7497258.194

Clearly the HP models algorithms deviates somehow from the expected result, contrary to what the Walter&Pauli algorithms which are giving fantastic close results.

As Pauli has mentioned, the 34s is giving the correctly rounded result to 16 digits.

Likewise, I believe you will find that the Prime/50g results listed above are the correctly rounded results to 12 digits for a 12-digit input parameter.

In other words, the results are not for the exact value of 355/226, but rather 355/226 rounded to x digits.

For what it's worth, a SysRPL program using 15-digit extended reals on a 50g gives a result of -7.49725824999067E6 (-7497258.24999067). A quick check with Wolfram Alpha shows this to be a correctly rounded result to 15 digits for the 15-digit input of "tan(1.57079646017699)".