Matrix inversion function correctness issue
Posted Wednesday, 21 April, 2010 - 08:02 by pontifikas| Project: | The Open Toolkit library |
| Version: | 1.0.0-rc1 |
| Component: | Code |
| Category: | bug report |
| Priority: | normal |
| Assigned: | Unassigned |
| Status: | confirmed |
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Description
Matrix "Invert" method returns incorrect results.
The matrix referenced below is Singular. However, Invert method returns a result.
Matrix "sumC" is of type "dnAnalytics.LinearAlgebra.SparseMatrix" of the dnAnalytics library and correctly recognizes the matrix as Singular.
The data were alse checked with Matlab and again the Matrix was found to be singular.
//Values Matrix4d Mat = new Matrix4d(sumC[0, 0], sumC[0, 1], sumC[0, 2], sumC[0, 3], //(2.37972721044496, 0, -0.0993767007536986, -0.745316262570544) sumC[1, 0], sumC[1, 1], sumC[1, 2], sumC[1, 3],//(0, 0, 0, 0) sumC[2, 0], sumC[2, 1], sumC[2, 2], sumC[2, 3],//(-1.76508718476331, 0, 1.0137436046165, 0.895168793026055) sumC[3, 0], sumC[3, 1], sumC[3, 2], sumC[3, 3]);//(0, 0, 0, 1) Mat.Invert();//Passes and returns: //(0.42021623134402, 0, -0.0417597026741217, 0.313193991016804) //(0, 0, 0, 0) //(0.741718284774864, 0, 0.94003408858688, -0.342354093137419) //(0, 0, 0, 1) sumCInv = (SparseMatrix)sumC.Inverse();//Throws Singularity exception
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