Floating point "closeness" predicate

[epage]

This isn't needed for any of my cases but just wanted to bring it up for rounding things out.

Floating point equality is weird. Generally, its best to do a "closeness" check.

[epage]

Hamcrest seems to have this
https://github.com/ujh/hamcrest-rust/blob/master/src/matchers/close_to.rs

[epage]

float_cmp might be useful for this
https://mikedilger.github.io/float-cmp/float_cmp/index.html

See also

• https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
• http://floating-point-gui.de/errors/comparison/