Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
The essential difference between the first assignments to $x and $y, and the assignments made later (in the "#now with simpler math" section) is that while 2, 1.25, 5, and 0.5 can *all* be represented exactly in base 2, the same cannot be said of 0.95, 806, 1.3 and 589.
Sure ... both 806 and 589 can be represented exactly in base 2, but 0.95 and 1.3 cannot.

Hence the first calculations do not yield "expected" values, whereas the second calculations *do* yield expected values.

Workarounds include doing base 10 calculations - eg by using Math::Decimal (pure perl) or Math::Decimal64 (XS access to the C compiler's _Decimal64 arithmetic).


In reply to Re: Comparing results of math operations by syphilis
in thread Comparing results of math operations by stangoesagain

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others rifling through the Monastery: (13)
    As of 2015-11-30 09:43 GMT
    Find Nodes?
      Voting Booth?

      What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

      Results (769 votes), past polls