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    <p>I dug a bit for you, and I think you might be able to use the <code>struct</code> module in combination with the information on at <a href="http://babbage.cs.qc.edu/courses/cs341/IEEE-754references.html#kevin_chart" rel="nofollow noreferrer">Kevin's Summary Charts</a>. They explain the exact bit patterns used for the various kinds of IEEE 754 floating point numbers.</p> <p>The only thing you probably will have to be careful for, if I read the topics on this <code>IND</code>-eterminate value, is that that value tends to trigger some kind of floating point interrupt when assigned directly in C code, causing it to be turned into a plain NaN. Which in turn meant those people were advised to do this kind of thing in ASM rather than C since C abstracted that stuff away.. Since it is not my field, and that I am not sure to what extent this kind of value would mess with Python, I figured I'd mention it so you can at least keep an eye for any such weird behaviour. (See the accepted answer for <a href="https://stackoverflow.com/questions/2247447/usefulness-of-signaling-nan">this question</a>).</p> <pre><code>&gt;&gt;&gt; import struct &gt;&gt;&gt; struct.pack("&gt;d", float('nan')).encode("hex_codec") 'fff8000000000000' &gt;&gt;&gt; import scipy &gt;&gt;&gt; struct.pack("&gt;d", scipy.nan).encode("hex_codec") '7ff8000000000000' </code></pre> <p>Referring to <a href="http://babbage.cs.qc.edu/courses/cs341/IEEE-754references.html#kevin_chart" rel="nofollow noreferrer">Kevin's Summary Charts</a>, that shows that <code>float('nan')</code> is actually technically the Indeterminate value, while <code>scipy.nan</code> is a Quiet NaN.</p> <p>Let's try making a Signaling NaN, and then verify it.</p> <pre><code>&gt;&gt;&gt; try_signaling_nan = struct.unpack("&gt;d", "\x7f\xf0\x00\x00\x00\x00\x00\x01")[0] &gt;&gt;&gt; struct.pack("&gt;d", try_signaling_nan).encode("hex_codec") '7ff8000000000001' </code></pre> <p>No, the Signaling NaN gets converted to a Quiet NaN.</p> <p>Now let's try making a Quiet NaN directly, and then verify it.</p> <pre><code>&gt;&gt;&gt; try_quiet_nan = struct.unpack("&gt;d", "\x7f\xf8\x00\x00\x00\x00\x00\x00")[0] &gt;&gt;&gt; struct.pack("&gt;d", try_quiet_nan).encode("hex_codec") '7ff8000000000000' </code></pre> <p>So that's how to make a proper Quiet NaN using <code>struct.unpack()</code>--at least, on a Windows platform.</p>
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    1. POHow to distinguish different types of NaN float in Python
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    1. COThanks for your answer Stigma. I've taken the liberty of editing it to add code samples. Much appreciated.
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    2. COI'm glad you got out of it what you needed, and thank you for adding the code samples for others like myself to learn from. :)
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    3. CONice -- thanks.
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