Hi Motes,<br><br><br> "Glimpsing at the source leaves no doubt"<br><br><br>If you look at itkTransform.h,<br><br>the type of the Jacobian matrix is an itkArray2D<double><br><br>The itkArray2D<T> derives from the vnl_matrix<T><br>
<br>When you call "size()" you are calling the "size()" method<br>of the vnl_matrix:<br><br><br>which is defined in:<br><br>Insight/Utilities/vxl/core/vnl/vnl_matrix.h in line 157 as:<br><br> unsigned size() const { return rows()*cols(); }<br>
<br><br>So, yes,<br>The value returned by "size()" is the total number of<br>elements in the matrix.<br><br><br> Regards,<br><br><br> Luis<br><br><br>------------------------------------------------------------------------------------------<br>
<div class="gmail_quote">On Sun, Sep 6, 2009 at 6:24 AM, motes motes <span dir="ltr"><<a href="mailto:mort.motes@gmail.com">mort.motes@gmail.com</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;">
I am using the BSplineDeformableTransform in a 2D registation application.<br>
<br>
I am using a cubic BSpline, order=3 and have choosen to cover the<br>
image with 5*5 nodes. The total nodes are 8*8 = 64 (3 boundary nodes<br>
in each dimension). Since I am working in 2D I get 64*2=128<br>
coefficients. And since I am using a third order BSpline I get<br>
(3+1)*(3+1) = 16 weights for each pixel.<br>
<br>
When I print the m_Jacobian:<br>
<br>
std::cout << "m_Jacobian size = " << m_Jacobian.size() << std::endl;<br>
<br>
from the GetJacobian() function I get the size:<br>
<br>
256.<br>
<br>
I thought that the jacobian was a matrix with number of rows equal to<br>
the dimension (2) and number of columns equal to the number of<br>
parameters (128). But maybe the two rows are just concatenated into a<br>
flat array:<br>
<br>
[x0,x1,x2,...,xN, y0,y1,...,yN]<br>
<br>
like the parameters array?<br>
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