[xsl] Unexpected result in sum

["Angela Williams" <Angela.Williams@xxxxxxxxxxxxxxxxxx>]

Why does this not output 0.00?  When formatted, I end up with -$0.00.

I've read what I can find on negative zero, but can't see how this node
set and operation could produce it.

Using Saxon 8.9 processor (internal to Oxygen.)

Input:
<?xml version="1.0" encoding="UTF-8"?>
<a>
    <b>1103.86</b>
    <b>1829.30</b>
    <b>-853.77</b>
    <b>-243.17</b>
    <b>-1.11</b>
    <b>-1296.66</b>
    <b>588.52</b>
    <b>849.25</b>
    <b>-1976.22</b>
</a>

Output:
<?xml version="1.0" encoding="UTF-8"?>
<a>
   <sum-b>-2.2737367544323206E-13</sum-b>
   <sum-nodes>-2.2737367544323206E-13</sum-nodes>
</a>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
version="2.0">
    <xsl:output method="xml" indent="yes"/>

    <xsl:template match="/a">
        <a>
            <sum-b>
                <xsl:value-of select="sum(b)"/>
            </sum-b>

            <xsl:variable name="nodes" select="b"/>

            <sum-nodes>
                <xsl:value-of select="sum($nodes)"/>
            </sum-nodes>
        </a>
    </xsl:template>
</xsl:stylesheet>

Thanks!
Angela Williams
Office: 512.344.1547 ~ Fax: 512.397.6656
Angela.Williams@xxxxxxxxxxxxxxxxxx