GMP 6 the incomatible GMP?

Torbjorn Granlund tg at
Tue Jan 8 00:28:07 CET 2013

nisse at (Niels Möller) writes:

  Hmm. I guess one could go down to only 8 bits or so for the alloc field,
  and for larger allocations, store the number of allocated limbs at the
  head of the limb array (in the case limb size is not artificially small,
  it could be just _mp_d[-1]).
That's another idea.

  Do you think 48 bits (or 47 bits absolute value) for _mp_size will be
  large enough for the foreseeable future (say, 10 years)?
I think that will be sufficient for some hundred years, since any
super-linear algorithm applied to an operand of 2^53 bits (2^47 64-bit
limbs) would hardly ever terminate even with a multi-THz CPU.

  There are also other tweaks discussed for mpz_t, to allow initialization
  without allocation.

Yep, we should do that too.  I cannot recall the details, but I assume
that this would not create an incompatibility?


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