<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello Shijie,<div><br></div><div>Yes, its the factors in the recursion relationship that we were surprised to find, as the rest the </div><div>recursion relationship steps are the same as that in Numerical recipes...I'm glad to know that this</div><div>is stable for large L as we'll be going up to about L=360. Any chance that there's a reference</div><div>for the recursion relationship (or maybe point us in the right direction, we've looked up several others</div><div>and haven't found the same thing)? No hurry, but it seems like this is a good thing to have reference for general</div><div>CitcomS background information too.</div><div><br></div><div>Thanks for answering our e-mail so quickly,</div><div>Magali</div><div><br><div><div>On Mar 3, 2010, at 5:13 PM, Shijie Zhong wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="font-family: monospace; ">You are right that the recursion relation for the Legendre polynomials used in<span class="Apple-converted-space"> </span><br>CitcomS is different from the standard in Numerical Recipes by Press. The<span class="Apple-converted-space"> </span><br>standard one in Numerical Recipes blows up for spherical harmonic degree l ><span class="Apple-converted-space"> </span><br>20 or something, even with double precision computation. I re-derived a<span class="Apple-converted-space"> </span><br>recursion relation in 1997 that is stable for nearly all l's and is used in CitcomS.<span class="Apple-converted-space"> </span></span></span></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>-----------------------------</div><div>Associate Professor, U.C. Davis</div><div>Department of Geology/KeckCAVEs</div><div>Earth & Physical Sciences Bldg, rm 2129</div><div>Davis, CA 95616</div><div>-----------------</div><div><a href="mailto:mibillen@ucdavis.edu">mibillen@ucdavis.edu</a></div><div>(530) 754-5696</div><div><b>--------------------------</b></div><div><b>** Note new e-mail, building, office</b></div><div><b> information as of Sept. 2009 **</b></div><div>-----------------------------</div></div></div></span></div></span></div></span> </div><br></div></body></html>