Review Request: BigInteger patch for efficient multiplication and division (#4837946)

Alan Eliasen eliasen at
Mon Mar 4 23:24:16 UTC 2013

On 03/04/2013 03:37 PM, Dr Heinz M. Kabutz wrote:
> Whilst we're at it, could we also add an option, perhaps via
> environment variable, to parallelize Karatsuba and other calculations?
> Here's an article I wrote about the inefficiencies of BigInteger and
> working out large numbers:

   That's an interesting article, thanks.

   When I first made the patches for faster multiplication, I was asked
to generate small, simple patches so that they would be reviewed more
rapidly.  I didn't make any attempt to use multiple threads, although
these recursive divide-and-conquer algorithms would seem to be good
candidates for such algorithms

   Brian, as you may also not know, I have further patches to
drastically improve the toString behavior of BigInteger using
Schoenhage-Strassen recursive decomposition.  This makes toString orders
of magnitude faster for large numbers and will likely improve the
performance of some of the stuff you're doing in BigDecimal as well.  I
will polish those up and submit them when you've reviewed the
multiplication and pow fixes.

  Alan Eliasen
  eliasen at

More information about the core-libs-dev mailing list