Hi Christian,<br><br><br>This optimizer does the following<br><br><br> A) Compute Gradient of the Cost function at initial point<br> B) Use current step length to multiply the unit vector <br> of the gradient computed in (A)<br>
C) Jump from current point to new point using the vector<br> computed in (B)<br> D) compute direction of jump in (B) with the one of the <br> previous iteration (by scalar product).<br> E) If directions are opposite, then reduce Step Length<br>
by the "Relaxation factor" (which by default is 0.5).<br> F) If current Step length is larger than Minimum Step <br> length then goto (A).<br> G) Otherwise, stop.<br><br><br><br> Regards,<br>
<br><br> Luis<br><br><br>--------------------------------------------<br><div class="gmail_quote">On Fri, Jul 24, 2009 at 1:26 PM, c23562 <span dir="ltr"><<a href="mailto:c.popko@gmx.de">c.popko@gmx.de</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>
Hi all,<br>
<br>
Where i can learn something about the workings of RegularStepGradientDescent<br>
Optimizer? I would like to know what exacly is a step? What is changing when<br>
doing a step?<br>
I have an imagine about regularStepGradientDescent optimizer and translation<br>
transform but what about BSplineDeformable transform? I have no idea what<br>
happens if the optimizer is working.<br>
I have read the ITKSoftwareGuide and read all lectures. There is described<br>
what happens if the optimizer is used with curves like parabolas but what<br>
about the contour lines in BSplineDeformableTransform?<br>
<br>
Thanks in advance and best regards,<br>
Christian<br>
--<br>
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