Appendix C
Transfer Matrix Inversion
To invert one matrix P, the various steps are as follows:
- calculate its determinant det(P)
- calculate the cofactor pij of each element, starting from the determinant of the corresponding minor matrix P{ij} of P, i.e. the matrix P, in which one removes the row i and the column j:
(C.1)
- constitute the cofactor matrix, or the matrix of the cofactors:
(C.2)
- calculate the transpose cofactor matrix com(P)T, adjugate of P
- calculate the inverse of P by:
(C.3)
These algebraic calculations are heavy, rather than complex. We will, however, carry them out for the IPM-SM, for inverting the transfer matrix P (equation (B.37)); this result is indeed necessary to calculate the control vector.
The following calculations will not detail the intermediate calculation of the coefficients cij of the adjugate of the P matrix, since it is enough to:
- calculate the 3 × 3 determinants of the minor matrices of P, using Cramer’s rules
- give to the determinants, the corresponding sign (−1)i + j
- invert the subscripts i and j to create the coefficients cpij, of the adjugate matrix:
(C.4)
To calculate the inverse matrix P− 1, we will thus calculate firstly the determinant of the transfer ...
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