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Bruno Vincent Richefeu a écrit :
If 'eigen' is used instead of Wm3 to find principal axes of inertia, eigenvalues must NOT be ordered (as Wm3 do).So don't forgot to disable "ordering" in 'eigen' (if possible) Le 8 févr. 2010 à 17:05, Anton Gladky a écrit :Thanks for comments. You are right, eigendecomposition in yade uses in:- Tetra.cpp { * The inertia tensor is in global coordinates; by eigendecomposition, we find principal axes}- Clump.cpp We have a next comment there: http://bazaar.launchpad.net/%7Eyade-dev/yade/trunk/annotate/head%3A/pkg/dem/DataClass/Clump.cpp#L240/*! @bug eigendecomposition might be wrong. see http://article.gmane.org/gmane.science.physics.yade.devel/99 for message. It is worked around below, however.*/ Vaclav, it seems, it is your comment. So, we just let it be? ______________________________ Anton Gladkyy2010/2/8 Vincent Richefeu <richefeu@xxxxxxxxxxxxxxx <mailto:richefeu@xxxxxxxxxxxxxxx>>if numerical recipes, numpy and eigen give the same result, we can have some confidence with this result. It means that Wm3 result is "less good". However, I don't know where eigen values and vectors are needed in yade (maybe for the computation of inertia?). I don't know if my comments help (sorry), but all I can say is that eigenvalues from Wm3 seems correct but unordered, and eigenvectors seems not well converged (maybe it is not a problem) Le 8 févr. 2010 à 16:21, Anton Gladky a écrit :Vincent, what do you think, if we use these "new values" it will not work? ______________________________ Anton Gladkyy 2010/2/8 Vincent Richefeu <richefeu@xxxxxxxxxxxxxxx <mailto:richefeu@xxxxxxxxxxxxxxx>> Hi, At first glance, it seems the eigenvalues (and thus the eigenvectors) are not ordered with Wm3. The difference can also be due to the fact that the solution is not converged. If needed, I can send a peace of code (based on "jacobi" in numerical recipes) for doing that taskVRLe 8 févr. 2010 à 13:46, Anton Gladky a écrit :Thanks, Vaclav! So, it seems Wm3 is broken for that function? I have taken another matrix, which is positive definite: 1 7 3 6 2 4 2 5 3 ======================== Eigen gives: Rot: -0.584754 -0.665682 -0.466054 -0.617452 0.703421 -0.301128 -0.526133 -0.266722 0.841805 Diag: 11.0907 0 0 0 -5.19482 0 0 0 0.104141 ======================== Numpy gives (see checkEigen.py): Rot: array([[-0.58475406, -0.66268234, -0.46225138], [-0.61745205, 0.70025076, -0.29867115], [-0.52613273, -0.26552022, 0.83493665]]) Diag: array([ 11.09067395, -5.1948153 , 0.10414135]) So, it was similar to Eigen results. ======================== But Wm3: Rot: 0.710682 0.404879 0.57533 -0.699213 0.316215 0.641178 0.0776719 -0.857952 0.507825 Diag: -5.55916 0 0 0 0.10998 0 0 0 11.4492 ======================== Is it the Wm3 library problem? ______________________________ Anton Gladkyy 2010/2/8 Václav Šmilauer <eudoxos@xxxxxxxx <mailto:eudoxos@xxxxxxxx>> > I'm trying to create a wrapper for Eigen library. Almost all functions > are already done, but I have a problem with EigenDecomposition. > Unfortunately, I never used this functions and do not clearly > understand what it implements. > > Eigen library has an EigenSolver for those tasks > http://eigen.tuxfamily.org/dox/classEigen_1_1EigenSolver.html > > I tried to get all values from that solver and compare with results, > what Wm3 gives. It is completely different. Using numpy to check: >>> from numpy import array >>> fron numpy.linalg import eig >>> a=array([[-26.8141,20.0536,-37.6382],[-17.0536,-4.37217,13.4546],[39.0891,8.34892,-21.6416]]) >>> eig(a) ## http://docs.scipy.org/doc/numpy/reference/generated/numpy.linalg.eig.html (array([-26.91393664+42.69101435j, -26.91393664-42.69101435j, 1.00000328 +0.j ]),array([[ 0.70584131+0.j , 0.70584131+0.j , 0.05979811+0.j ],[-0.03806586+0.30786093j, -0.03806586-0.30786093j, 0.89863520+0.j ], [-0.01840919-0.63657033j, -0.01840919+0.63657033j, 0.43460208+0.j ]])) You've picked matrix that has complex eigenvalues, that explains the difference; eigen handles it just fine ("(real,imag)" notation), wm3 obviously doesn't. (the matrix should be positive definite for real eigenvalues, iirc). Cheers, Vaclav > Here is the source matrix: > > -26.8141 20.0536 -37.6382 > -17.0536 -4.37217 13.4546 > 39.0891 8.34892 -21.6416 > > > ======================= > wm3: > > tRot: > -0.698021 -0.0166317 -0.715884 > 0.339616 -0.887829 -0.310515 > -0.630419 -0.459872 0.625372 > > tDiag: > -70.5641 0 0 > 0 2.97262 0 > 0 0 14.7635 > > ======================= > Eigen: > eigenvalues: > (-26.91,42.69) > (-26.91,-42.69) > (1,0) > > eigenvectors: > (-0.117,0.6961) (-0.117,-0.6961) (0.0598,0) > (-0.2973,-0.08855) (-0.2973,0.08855) (0.8986,0) > (0.6308,0.08732) (0.6308,-0.08732) (0.4346,0) > > pseudoEigenvalueMatrix: > -26.91 42.69 0 > -42.69 -26.91 0 > 0 0 1 > > pseudoEigenvectors: > -0.1654 0.9844 0.0598 > -0.4204 -0.1252 0.8986 > 0.8921 0.1235 0.4346 > ======================= _______________________________________________ Mailing list: https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> Post to : yade-dev@xxxxxxxxxxxxxxxxxxx <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx> Unsubscribe : https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> Post to : yade-dev@xxxxxxxxxxxxxxxxxxx <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx> Unsubscribe : https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> More help : https://help.launchpad.net/ListHelp_______________________________________________ Mailing list: https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> Post to : yade-dev@xxxxxxxxxxxxxxxxxxx <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx> Unsubscribe : https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> Post to : yade-dev@xxxxxxxxxxxxxxxxxxx <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx> Unsubscribe : https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> More help : https://help.launchpad.net/ListHelp_______________________________________________ Mailing list: https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> Post to : yade-dev@xxxxxxxxxxxxxxxxxxx <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx> Unsubscribe : https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> More help : https://help.launchpad.net/ListHelp _______________________________________________Mailing list: https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev> Post to : yade-dev@xxxxxxxxxxxxxxxxxxx <mailto:yade-dev@xxxxxxxxxxxxxxxxxxx> Unsubscribe : https://launchpad.net/~yade-dev <https://launchpad.net/%7Eyade-dev>More help : https://help.launchpad.net/ListHelp------------------------------------------------------------------------ _______________________________________________ Mailing list: https://launchpad.net/~yade-dev Post to : yade-dev@xxxxxxxxxxxxxxxxxxx Unsubscribe : https://launchpad.net/~yade-dev More help : https://help.launchpad.net/ListHelp
-- _______________ Bruno Chareyre Associate Professor Grenoble INP Lab. 3SR BP 53 - 38041, Grenoble cedex 9 - France Tél : 33 4 56 52 86 21 Fax : 33 4 76 82 70 43 ________________
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