<div dir="ltr">Laura,<br><br>Quoting from the documentation for "where":<br><br>"Caveat: NCL evaluates the entire expression inside the where function, which will cause problems if it's an expression NCL would normally fail on."<br><br>There is more than one way to fix this. This is my preferred method because it is self documenting.<br><br>rain@_FillValue = default_fillvalue(typeof(rain))<br> ; do this only if rain does not already have a good _FillValue<br><br>divisor = where (rain .ne. 0, rain, rain@_FillValue)<br>ratio_rainc = where (rain .gt. 5., rainc / divisor, rain@_FillValue)<br><br>That was a general solution. You have a special case where the two conditionals overlap, so one of them is unnecessary. You could merge conditionals like this:<br><br>divisor = where (rain .gt. 5, rain, rain@_FillValue)<br>ratio_rainc = rainc / divisor<br><br>--Dave<br><div class="gmail_extra"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Nov 7, 2016 at 11:59 AM, Laura Fowler <span dir="ltr"><<a href="mailto:laura@ucar.edu" target="_blank">laura@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Hello:<br>
<br>
I am trying to get around the error message:<br>
<br>
fatal:divide: Division by 0, Can't continue<br>
fatal:Div: operator failed, can't continue<br>
<br>
when trying to calculate the ratio between the convective rain and<br>
total rain on a global scale. To avoid dividing by zero, I defined the<br>
missing value:<br>
<br>
rain@_FillValue = default_fillvalue(typeof(rain)<wbr>)<br>
<br>
prior to the line:<br>
<br>
ratio_rainc = where(rain.gt.5.,rainc/rain,<wbr>rain@_FillValue)<br>
<br>
I thought that this would solve the issue of dividing by zero, but it<br>
did not. I am not sure what to try next?<br>
<br>
Thanks,<br>
Laura<br></blockquote></div></div></div>