Hi,<div><br></div><div>I&#39;m using the axis_and_angle_as_r3_rotation_matrix method of scitbx.matrix.col in some Python code. Now I need to calculate the first derivative of the rotation matrix with respect to the rotation angle. Is there a function to do that somewhere in scitbx (or elsewhere in cctbx)? I had a brief look around but couldn&#39;t find anything that looked hopeful.</div>

<div><br></div><div>If there isn&#39;t something there already I have some Fortran code from David Thomas that I could adapt to do this. Of course it wouldn&#39;t be very efficient in pure Python, and calculating the matrix and its derivative separately, but that&#39;s okay for now as the code is just for testing out some ideas.</div>

<div><br></div><div>By the way, links to <a href="http://skal.planet-d.net/demo/matrixfaq.htm">http://skal.planet-d.net/demo/matrixfaq.htm</a> in the documentation (e.g. <a href="http://cctbx.sourceforge.net/current/c_plus_plus/namespacescitbx_1_1math_1_1r3__rotation.html#aaa200e3366d2e91e0ba9e01ecf99e99e">here</a>) are broken. I found a document with the same name here: <a href="http://vamos.sourceforge.net/matrixfaq.htm">http://vamos.sourceforge.net/matrixfaq.htm</a>, but I have no idea if this has the same content as the original.</div>

<div><br></div><div>Cheers</div><div><br>-- David<br>
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