Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview?

[Paul Dale]

(03-16-2014 01:45 PM)Werner Wrote:  in DEG mode:
SIN(180°+x) = -SIN(x) fails for x=10^-31, 10^-30, 10^-16 ... and many more (these fail on the WP34 as well btw)

I'm not surprised here. 180 + 10^-31 is pushing the number of digits in double precision whereas -10^-31 isn't stretching anything. In single precision there doesn't seem to be an issue thankfully.

I know the 34S trigonometric functions don't do the usual full reduction to the first octant before evaluating the functions. I brute force things with a longer series -- it is smaller codewise. There is also the conversion to radians involved to disturb the results a bit.

In summary:

* not unexpected,
* doesn't impact single precision,
* will take space to fix.

Is it worthwhile trying? I'll see if I can come up with something nice and simple.


- Pauli