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Question G4RotationMatrix defined by specifying actual Matrix gives warning 

Keywords: G4RotationMatrix, round-off errors
Forum: Geometry
Date: 20 Oct, 2006
From: Ioannis Sechopoulos <Ioannis Sechopoulos>

Hello, I am defining a G4RotationMatrix to rotate a volume using:

A = new G4RotationMatrix(G4ThreeVector(alpha1, alpha2, alpha3),
				G4ThreeVector(beta1, beta2, beta3),
				G4ThreeVector(gamma1, gamma2, gamma3));

which specifically defines the rotation matrix according to the header file. alpha1, alpha2, etc are all floats. I get the following warnings:

ZMxpvNotOrthogonal:

ZMxpvNotOrthogonal: col's X and Y supplied for Rotation are not close to orthogonal
at line 86 in file RotationC.cc ZMxpvNotOrthogonal:
ZMxpvNotOrthogonal: col's X and Z supplied for Rotation are not close to orthogonal
at line 92 in file RotationC.cc ZMxpvNotOrthogonal:
ZMxpvNotOrthogonal: col's Y and Z supplied for Rotation are not close to orthogonal

I checked, and the rotation matrix is not exactly orthogonal because transpose(A)*A gives me almost the identity matrix but with small round off errors in the fourth decimal place. Will I face a problem if I still use this RotationMatrix? The volume appears fine in graphical output, but I am concerned that maybe the Navigator will run into trouble.

Thanks!

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1 Feedback: Re: G4RotationMatrix defined by specifying actual Matrix gives warning   (Gabriele Cosmo - 25 Oct, 2006)
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