Boost C++ Libraries: Ticket #8798: pow(cpp_dec_float_type(0), cpp_dec_float_type(n)) != 0 for n > 1

attachment set

Mon, 08 Jul 2013 12:47:17 GMT

attachment → boost_multiprecision_power_demo.cpp

Demonstration of the error

attachment set

Mon, 08 Jul 2013 13:06:23 GMT

attachment → boost_multiprecision_power_demo.2.cpp

Demonstration of the error - without annoyance, please remove previous

Tue, 09 Jul 2013 06:04:28 GMT

Output of the attached code:

pow(0, 0) = 1
pow(0, 1) = 0
pow(0, 2) = 0
pow(1, 0) = 1
pow(1, 1) = 1
pow(1, 2) = 1
pow(2, 0) = 1
pow(2, 1) = 2
pow(2, 2) = 4
pow(0, 0) = 1
pow(0, 1) = 0
pow(0, 2) = 1 - Unexpected!
pow(1, 0) = 1
pow(1, 1) = 1
pow(1, 2) = 1
pow(2, 0) = 1
pow(2, 1) = 2
pow(2, 2) = 4
pow(0, 0) = 1
pow(0, 1) = 0
pow(0, 2) = 1 - Unexpected!
pow(1, 0) = 1
pow(1, 1) = 1
pow(1, 2) = 1
pow(2, 0) = 1
pow(2, 1) = 2
pow(2, 2) = 4
pow(0, 0) = 1
pow(0, 1) = 0
pow(0, 2) = 1 - Unexpected!
pow(1, 0) = 1
pow(1, 1) = 1
pow(1, 2) = 1
pow(2, 0) = 1
pow(2, 1) = 2
pow(2, 2) = 4

status changed; resolution set

John Maddock — Wed, 10 Jul 2013 16:08:14 GMT

status new → closed
resolution → fixed

(In [84997]) Fix bug in eval_pow that causes 0^{N to be none-zero.
Fixes #8798.}