I hadn't tried that. Thanks.
Prior to replacing product() with sProduct(), my earlier non-factoring versions would not have produce a result because the intermediate terms blew the range of a double. That's what originally necessitated the introduction of M::BF and yielded the 4 1.2 hrs runtime.
sProduct() effectively gives me a cheap "BigFloat", and negates the need for the factoring.
Just goes to show there is more than one way to skin a cat :)
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.