Gradient matrix in Eigen?

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vernal Registered Member Posts 37 Karma 0	Gradient matrix in Eigen? Tue Feb 01, 2011 9:54 am Hi all does Eigen provide a way to calculate a numerical gradient matrix the way Matlab does with the gradient command? Matlab sample: Code: Select all `A=magic(5) [dAx dAy] = gradient(A)` If not, is there some (clever) implementation of the Matlab diff functionality in Eigen? Regards vernal
jitseniesen Registered Member Posts 204 Karma 2	Re: Gradient matrix in Eigen? Tue Feb 01, 2011 2:55 pm I don't think Eigen has something like Matlab's gradient. However, Matlab's diff can easily be translated into Eigen code: Code: Select all `dAx = A.rightCols(A.cols()-1) - A.leftCols(A.cols()-1); // Matlab: dAx = diff(A,1,2) dAy = A.bottomRows(A.rows()-1) - A.topRows(A.rows()-1); // Matlab: dAy = diff(A)`
vernal Registered Member Posts 37 Karma 0	Re: Gradient matrix in Eigen? Wed Feb 02, 2011 11:31 am Thank you! Do you know if this formulation in Eigen can be optimized by the compiler (using SSE etc.)?
bjacob Registered Member Posts 658 Karma 3	Re: Gradient matrix in Eigen? Wed Feb 02, 2011 1:56 pm If your matrices are dynamic-sized (as in MatrixXf) and large enough, Eigen will vectorize that. Join us on Eigen's IRC channel: #eigen on irc.freenode.net Have a serious interest in Eigen? Then join the mailing list!
vernal Registered Member Posts 37 Karma 0	Re: Gradient matrix in Eigen? Thu Feb 03, 2011 4:46 pm Thank you for that clear statement