On Dec 4, 2013, at 6:56 PM, Joe Darcy wrote: > As a double-check, can you run the now failing regression test against the > earlier versions of java.math.* between when Karatsuba and friends went in > and the current version of the code?
If I go back to rev 7466 changeset: 7466:9b802d99cb52 user: bpb date: Wed Jun 19 08:59:39 2013 -0700 summary: 4837946: Faster multiplication and exponentiation of large integers changeset: 4554:2a8072c7cf99 user: darcy date: Wed Sep 14 11:32:11 2011 -0700 summary: 6879143: java.math.BigInteger misses the xxxValueExact methods which is when Karatsuba, et. al., were introduced, then the code as-is in 7466 passes the test in question, but if I change the two multiplication thresholds to the current values without modifying anything else, the test fails with similar errors to what was observed for the current tip. It seems the threshold change exposes a different profile of numbers to the algorithm which reveals the problem. I highly doubt any intervening changes are behind this. Brian
