<div dir="ltr">Thanks!<div>I&#39;ll try CReal.<br><div>But can I set <strong style="font-size:13px;font-weight:normal;color:rgb(204,0,0);font-family:Arial,Helvetica,sans-serif;line-height:18px">significant figures </strong><strong style="font-size:13px;font-weight:normal;font-family:Arial,Helvetica,sans-serif;line-height:18px"><font color="#000000">myself?</font></strong></div>
</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Feb 6, 2013 at 6:50 AM, Brandon Allbery <span dir="ltr">&lt;<a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div class="h5">On Tue, Feb 5, 2013 at 5:41 PM, yi lu <span dir="ltr">&lt;<a href="mailto:zhiwudazhanjiangshi@gmail.com" target="_blank">zhiwudazhanjiangshi@gmail.com</a>&gt;</span> wrote:<br>
</div></div><div class="gmail_quote"><div><div class="h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr"><div>I found that in ghci, I input </div><div>[0.1,0.2..2]<br></div><div>and run, I get a result of </div><div><br></div><div>[0.1,0.2,0.30000000000000004,0.4000000000000001,0.5000000000000001,0.6000000000000001,0.7000000000000001,0.8,0.9,1.0,1.1,1.2000000000000002,1.3000000000000003,1.4000000000000004,1.5000000000000004,1.6000000000000005,1.7000000000000006,1.8000000000000007,1.9000000000000008,2.000000000000001]</div>


<div><br></div><div>But, as you know, it is not the exact answer.</div><div><br></div><div>So, I wonder if there is something I can do to achieve a better performance and get <span style="background-color:rgb(153,153,153)">[0.1,0.2,0.3,0.4..]</span> as the result.</div>

</div></blockquote><div><br></div></div></div><div>Welcome to the world of floating point numbers.  Perfect accuracy is not possible; the CReal type from the &quot;numbers&quot; package may handle cases you care about, or may not.  (Other languages often use output formats that can largely hide the errors, but they&#39;re still there and will eventually accumulate into visibility.)</div>
<span class="HOEnZb"><font color="#888888">
<div><br></div></font></span></div><span class="HOEnZb"><font color="#888888">-- <br><div dir="ltr"><div>brandon s allbery kf8nh                               sine nomine associates</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a>                                  <a href="mailto:ballbery@sinenomine.net" target="_blank">ballbery@sinenomine.net</a></div>

<div>unix, openafs, kerberos, infrastructure, xmonad        <a href="http://sinenomine.net" target="_blank">http://sinenomine.net</a></div></div>
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