title: How to alter a float by its smallest increment (or close to it)?
body: <p>I have a <code>double</code> value <code>f</code> and would like a way to nudge it very slightly larger (or smaller) to get a new value that will be as close as possible to the original but still strictly greater than (or less than) the original.</p>
  
  <p>It doesn't have to be close down to the last bit—it's more important that whatever change I make is guaranteed to produce a different value and not round back to the original.</p>