Hacker News Reader

I’m too late to update my own comment, but I now suspect BigFloat(π, precision=20000000) may allocate a Bigfloat with precision of two million digits and then store the constant π which has much lower precision in it.

What value does that print?

It definitely does calculate it otherwise it would diverge significantly at lower digits from the Gauss Legendre and Chudnovsky algorithm that I compared it to. It just defers calculation to MPFR, the C library Julia binds to for BigFloat calculations.

Also one additional comment is that you are setting precision in number of bits, not in decimal digits. It obviously runs much faster when it is only computing log2(20000000) not 20000000 digits of precision.

> (Plain Windows took ~26 seconds for some reason?)

Maybe the allocations were the reason?