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Sign upbracket_and_solve_root, toms748_solve; underflow when max_iter == 0 #138
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jzmaddock
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Aug 19, 2018
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jzmaddock commentedJul 31, 2018
~line 295, math/tools/toms748_solve.hpp
std::pair<T, T> toms748_solve(...)
Parameter max_iter is boost::uintmax_t. Line ~343 decrements count (--count) with no prior checks on the value of max_iter, resulting in an underflow if the provided max_iter==0.
This was discovered when calling bracket_and_solve root (with max_iters==15), which internally calls toms748_solve with max_iter==0, leading to the underflow/infinite(?) loop.
Unfortunately due to the nature of bracket_and_solve root I'm unable to provide a minimal repro, but to repro the underflow simply call toms748_solve with max_iter==0, which it does not appear to be checking against.
Alternatively/additionally, bracket_and_solve root is calling toms748_solve with max_iter==0; I don't know if that is desired behavior.
Moved from : https://svn.boost.org/trac10/ticket/13129