Re: [eigen] inconsistency in fast eigen decomposition |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] inconsistency in fast eigen decomposition*From*: Gael Guennebaud <gael.guennebaud@xxxxxxxxx>*Date*: Thu, 3 Feb 2011 14:58:34 +0100*Dkim-signature*: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:from:date :message-id:subject:to:content-type; bh=+1n5U6LrvoVwZRXEkXcgpkBTOcZMNukuCt3oP7Q0/KA=; b=Xw64+OIOePqXerR52FS0WC9RFoOCPELYiMcLP8Y5wslpDNhehTYLXI4s5CgdG9VTyi zMW3lMKB/YsFSkkOwwgaY+SKiWESKn/xSd8KqsqO2lTrMM/BKt3O8lYvho9Fg/4Sv/j9 SPwSBoD4856r7//ctH/+pFBXdlleN58Di0740=*Domainkey-signature*: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type; b=URWid7i2d49ib3Twk35CEY7x4aLqn9qgVTX98QLLt+9eK2+U1W17t5Yb7nNsgDfVW4 +9bVWX4iZfeInHbEVl5fZhkrbr5TjvnuswsNZ79Kz9eQNodL5WU7Jtna/QpTdoBVQf1s 2UYx54/cJlvtDEp886/iuXPxJJioYmLmerN0s=

he is not using something which is officially in eigen, but a function which is in bench/eig33.cpp that I added for benchmarking purpose and possible inclusion in Eigen in the future. The main question is how to integrate it (option of SelfAdjointEigenSolver, a new class, both...) That can be discussed for 3.1 since there already is a template Options parameter in SelfAdjointEigenSolver. gael On Thu, Feb 3, 2011 at 2:24 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote: > Could a unit test be added? Maybe just take his matrix, decompose, > reconstruct original matrix, compare. My understanding is that before > your fix, eigen would have given a completely wrong reconstructed > matrix, so just a fuzzy compare at default test precision would be > good enough. > > Benoit > > 2011/2/3 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>: >> yes but was is strange in Radu's example is that the direct method >> find a negative eigenvalue while they should all be positive (or equal >> to zero). I guess that's because of the multiple trigonometric >> functions. Anyway, now I start to compute the eigenvectors from the >> biggest eigenvalue and compute the last eigenvectors from the first >> two while taking care of some degenerated cases. >> >> gael >> >> On Thu, Feb 3, 2011 at 1:52 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote: >>> Yeah, it's hard to be accurate when there are degenerate eigenvalues. >>> Radu's example had well separated eigenvalues. >> >> >> > > >

**Follow-Ups**:**Re: [eigen] inconsistency in fast eigen decomposition***From:*Benoit Jacob

**References**:**[eigen] inconsistency in fast eigen decomposition***From:*Radu Bogdan Rusu

**Re: [eigen] inconsistency in fast eigen decomposition***From:*Gael Guennebaud

**Re: [eigen] inconsistency in fast eigen decomposition***From:*Benoit Jacob

**Re: [eigen] inconsistency in fast eigen decomposition***From:*Gael Guennebaud

**Re: [eigen] inconsistency in fast eigen decomposition***From:*Benoit Jacob

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