# Tetration Forum

Full Version: How to force precision in SAGE?
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I've been trying to remove some inaccuracy from my tetration library, and I keep getting precision limited to about 10-15 digits or so. I've finally figured out that despite using a RealField(256), which should provide at least a good 80 digits of precision, I'm getting truncations to double precision at some point. The net result is that I can perform a reversible series of transformations on 0 and get back numbers like -0.00000000718...

Needless to say, it's very frustrating. I haven't found a global setting in SAGE for the precision of real arithmetic, so I'm stuck having to push all my reversible transformations (like e^z-1 and ln(z+1)) through a RealField variable. Even then, I'm still losing precision somewhere. What's the "right" way to use arbitrary precision math in SAGE?

$e^z = \frac{e^z}{ln(b)}$, with b = 2.7182818284590458..., where that final 8 should be a 2.