Two prebuilt executables to use AUSAlib's geometry fitting routines. It contains two executables one for each routine. They handle the fitting and gives a nice graphical output. They are called IsotropicFitter and PolynomialFitter:
| n | Name of the detector to be calibrated | ``-n DSSSD1`` |
| p | Name of the hitpattern histogram in the input file | ``-p chits_DSSD1`` |
| o | Outputs the plot to a file. It can either be a pdf or root file. | ``-o output.pdf``|
| V | Outputs the full minimazation report | ``-V``|
| a | The isotropic fitter supports three fitting schemes: (N)eyman, (P)earson or (L)ikelihoodRatio. (IsotropicFitter only!) | ``-a L``|
| z | Fixes the local normal component when using the Isotropic fitter. (IsotropicFitter only!) | ``-z``|
# Error estimateion
The fits are performed in the local coordinate systems of the detectors. The fit thus give an error estimate in the local x, y and z direction, corresponding to global the `c=up.Cross(n)`, `up` and `n` directions. The transformation matrix from a point in the global coordinate system to a point in the local detector coordinate system is given as
Note that this will transform coordinates between the two system with a coinciding orego, but since we are interested in the error this will suffice for us. The reverse transformation is simply the inverse. From error propagation we can now calculate the covariance matrix on the coordinates in the global coordinate system as inv(A)*V*inv(A)^T. However, the inverse A is simply the transpose and we thus get A^T *V*A. The errors reported is the square root of the diagonal of this propagated error.
