<div dir="ltr">Hello,<div><br></div><div>I am trying to figure out how to calculate the following coefficients in the source code for the Radau integration method.</div><div><br></div><div><table class="gmail-highlight gmail-tab-size gmail-js-file-line-container" style="border-spacing:0px;border-collapse:collapse;color:rgb(36,41,46);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px"><tbody style="box-sizing:border-box"><tr style="box-sizing:border-box"><td id="gmail-LC37" class="gmail-blob-code gmail-blob-code-inner gmail-js-file-line" style="box-sizing:border-box;padding:0px 10px;line-height:20px;vertical-align:top;overflow:visible;font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,monospace;font-size:12px;white-space:pre"><span class="gmail-pl-c" style="box-sizing:border-box;color:rgb(106,115,125)"># Interpolator coefficients.</span></td></tr></tbody></table><span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">P</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">=</span> <span class="gmail-pl-s1" style="box-sizing:border-box">np</span>.<span class="gmail-pl-en" style="box-sizing:border-box;color:rgb(111,66,193)">array</span>([    [<span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">13</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">+</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">7</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">*</span><span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">S6</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>, <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">-</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">23</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">-</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">22</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">*</span><span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">S6</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>, <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">10</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">+</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">5</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">*</span> <span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">S6</span>], </div><div>  [<span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">13</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">-</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">7</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">*</span><span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">S6</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>, <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">-</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">23</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">+</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">22</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">*</span><span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">S6</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>, <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">10</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">-</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">5</span> <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">*</span> <span class="gmail-pl-v" style="box-sizing:border-box;color:rgb(227,98,9)">S6</span>],</div><div> [<span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">1</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>, <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">-</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">8</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>, <span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">10</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">/</span><span class="gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197)">3</span>]])  <br></div></div>