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greg sterijevski commented on MATH-320: --------------------------------------- Did anyone notice that the 3rd eigenvalue is negative? On my box the eigenvalue is -2.1028862676867717E-14. I am not sure what the fix was, but whatever problems existed still persist. > NaN singular value from SVD > --------------------------- > > Key: MATH-320 > URL: https://issues.apache.org/jira/browse/MATH-320 > Project: Commons Math > Issue Type: Bug > Affects Versions: 2.0 > Environment: Linux (Ubuntu 9.10) java version "1.6.0_16" > Reporter: Dieter Vandenbussche > Fix For: 2.1 > > > The following jython code > Start code > from org.apache.commons.math.linear import * > > Alist = [[1.0, 2.0, 3.0],[2.0,3.0,4.0],[3.0,5.0,7.0]] > > A = Array2DRowRealMatrix(Alist) > > decomp = SingularValueDecompositionImpl(A) > > print decomp.getSingularValues() > End code > prints > array('d', [11.218599757513008, 0.3781791648535976, nan]) > The last singular value should be something very close to 0 since the matrix > is rank deficient. When i use the result from getSolver() to solve a system, > i end > up with a bunch of NaNs in the solution. I assumed i would get back a least > squares solution. > Does this SVD implementation require that the matrix be full rank? If so, > then i would expect > an exception to be thrown from the constructor or one of the methods. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira