<div dir="ltr"><div class="gmail_quote"><div dir="ltr">On Sun, Nov 25, 2018 at 1:47 PM David Gobbi <<a href="mailto:david.gobbi@gmail.com">david.gobbi@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi Eric,<div><br></div><div>In your benchmarks, most of the time is going to the Python overhead. So I agree with your hypothesis: in Python, InsertPoint() will be faster than SetPoint() simply because the InsertPoint() only has 3 parameters while SetPoint() has 4. It's all about the time that Python takes to build the args tuple (function calls in Python are not cheap).</div></div></blockquote><div><br></div><div>Actually it's probably not just the Python function call overhead. The benchmark loop for SetPoint() also contains more operations and creates an additional variable.</div><div><br></div><div> David</div><div> </div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div class="gmail_quote"><div dir="ltr">On Sun, Nov 25, 2018 at 1:09 PM Fahlgren, Eric <<a href="mailto:eric.fahlgren@smith-nephew.com" target="_blank">eric.fahlgren@smith-nephew.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="blue" vlink="purple">
<div class="m_-3030390620558875841m_-9182447438078335742WordSection1">
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d">Using InsertPoint alone instead of SetPoint+Modified also pings the modified time, which brings us to an interesting side point.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d">We apparently had avoided InsertPoint due to performance issues in the past, so I benchmarked them and InsertPoint is now about 10% faster than SetPoint (which seems odd, since
you’d think InsertPoint would be doing some extra mallocs that are clearly </span>
<span style="font-family:Wingdings;color:#1f497d">J</span><span style="font-family:"Calibri","sans-serif";color:#1f497d"> more expensive than simple indexing). Maybe the extra data marshalling for the id parameter is the difference?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">from tools.timethis import timethis<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">import vtk<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">nPts = 5<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">points = vtk.vtkPoints()<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">for iteration in range(21):<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> print(f'{iteration:3d} {nPts:9_d}')<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> with timethis('Insert'):<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.SetNumberOfPoints(0)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> for i in range(nPts):<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> x = y = z = float(i)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.InsertNextPoint(x, y, z)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.InsertNextPoint(x+1, y+2, z+3)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> with timethis('Set'):<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.SetNumberOfPoints(nPts * 2)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> for i in range(nPts):<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> id = i*2<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> x = y = z = float(i)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.SetPoint(id+0, x, y, z)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.SetPoint(id+1, x+1, y+2, z+3)<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> points.Modified()<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> nPts *= 2<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> 0 5<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> 1 10<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console""> 2 20<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">...<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">18 1_310_720<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">19 2_621_440<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">20 5_242_880<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">Insert : 0.367240s : N= 21 : stddev=0.89898<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:11.0pt;font-family:"Lucida Console"">Set : 0.417269s : N= 21 : stddev=1.01908<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<div>
<div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> vtkusers [mailto:<a href="mailto:vtkusers-bounces@public.kitware.com" target="_blank">vtkusers-bounces@public.kitware.com</a>]
<b>On Behalf Of </b>Fahlgren, Eric<br>
<b>Sent:</b> Sunday, November 25, 2018 10:01 AM<br>
<b>To:</b> David Gobbi<br>
<b>Cc:</b> <a href="mailto:vtkusers@public.kitware.com" target="_blank">vtkusers@public.kitware.com</a><br>
<b>Subject:</b> Re: [vtkusers] vtkPoints.SetPoints bug?<u></u><u></u></span></p>
</div>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d">Thanks, David, that fixes it. I’m pretty surprised at this since the code was actually written back in the 5.2 days and hasn’t been touched since…<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d">Eric<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> David Gobbi [mailto:<a href="mailto:david.gobbi@gmail.com" target="_blank">david.gobbi@gmail.com</a>]
<br>
<b>Sent:</b> Sunday, November 25, 2018 8:25 AM<br>
<b>To:</b> Fahlgren, Eric<br>
<b>Cc:</b> <a href="mailto:vtkusers@public.kitware.com" target="_blank">vtkusers@public.kitware.com</a><br>
<b>Subject:</b> Re: [vtkusers] vtkPoints.SetPoints bug?<u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
<div>
<p class="MsoNormal">Hi Eric,<u></u><u></u></p>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">It's necessary to call Modified() after calling SetPoint() in order for ComputeBounds() to re-compute the bounds. This is because ComputeBounds() checks the timestamp and does nothing if the timestamp shows that the previous bounds are
still good.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">As far as I understand, vtkPoints has behaved this way for many years. Recently, however, there have been many changes to the VTK rendering pipeline that increase the reliance on timestamps. Perhaps in VTK 8.0 something was triggering a
Modified() call or was otherwise forcing a re-computation of the bounds.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal"> David<u></u><u></u></p>
</div>
</div>
</div>
</div>
</blockquote></div></div></div>
</blockquote></div></div>