<div dir="ltr"><div class="gmail_default" style="font-size:small">Kritanai,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">Yes, by default, this function will calculate the SPI by applying a 2-parameter gamma distribution fit, regardless of whether you have NCL Version 6.2.1 or 6.3.0.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">To get the Pearson type III distribution, you need to have NCL V6.3.0 or later, and you need to set:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small"> opt = True</div><div class="gmail_default" style="font-size:small"> opt@spi_type = 3</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">You can see full information on the dim_spi_n page:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style=""><a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_spi_n.shtml">http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_spi_n.shtml</a><br></div><div class="gmail_default" style=""><br></div><div class="gmail_default" style="">--Mary</div><div class="gmail_default" style=""><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sun, Apr 24, 2016 at 4:44 AM, Kritanai Torsri <span dir="ltr"><<a href="mailto:kritanai@haii.or.th" target="_blank">kritanai@haii.or.th</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear All,<br>
<br>
I used the "dim_spi_n" function with the Pearson type III to compute SPI.<br>
<br>
Am I correct that, by default, the NCL function still used the Maximum<br>
likelihood to estimate<br>
<br>
the location, scale, and shape of the gamma distribution as in<br>
two-parameter gamma distribution or it uses another method?<br>
<br>
If any one know, please give me suggestion and thanks in advance.<br>
<br>
BRGs,<br>
<br>
Kritanai Torsri<br>
<br>
Assistant Researcher<br>
<br>
Hydro and Agro Infomatics Institute, Bangkok, Thailand.<br>
<br>
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