Not a solution, but What Every Computer Scientist Should Know About Floating Point Arithmetic may help you understand what is happening and how to code to avoid the problems.

update: there are many surprising/disappointing features in floating point hardware and software. If you dump the internal representations of the values in your program, you might discern what is happening. I would consider whether values are rounded or truncated when converted from double to float, for example. It appears to be handled differently in the different contexts in your program. If you know what the conversion is doing, you should be able to test and make appropriate adjustments so that the result of the conversion is what you want. Alternatively, you might use a well defined/implemented function to perform the conversion rather than relying on the compiler built-in function.

In reply to Re: [Win32, C, and way OT] C floats, doubles, and their equivalence by ig
in thread [Win32, C, and way OT] C floats, doubles, and their equivalence by syphilis

Title:
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, details, 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, summary, 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.