Definition of pedigree in package pedigreemm
The numerator relationship matrix \(A\)
6 x 6 sparse Matrix of class "dsCMatrix"
1 2 3 4 5 6
1 1.00 . . 0.500 . 0.250
2 . 1.0 . 0.500 0.500 0.500
3 . . 1.00 . 0.500 0.250
4 0.50 0.5 . 1.000 0.250 0.625
5 . 0.5 0.50 0.250 1.000 0.625
6 0.25 0.5 0.25 0.625 0.625 1.125
The cholesky decomposition of \(A\)
1 2 3 4 5 6
1 1.00 0.0 0.00 0.0000000 0.0000000 0.0000000
2 0.00 1.0 0.00 0.0000000 0.0000000 0.0000000
3 0.00 0.0 1.00 0.0000000 0.0000000 0.0000000
4 0.50 0.5 0.00 0.7071068 0.0000000 0.0000000
5 0.00 0.5 0.50 0.0000000 0.7071068 0.0000000
6 0.25 0.5 0.25 0.3535534 0.3535534 0.7071068
To get to the matrix \(L\), we have to use the definition of \(R = L * S\) and \(S\) is the diagnoal matrix with elements corresponding to the square root of matrix \(D\). Matrix \(D\) can be obtained as
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 0 0 0.0 0.0 0.0
[2,] 0 1 0 0.0 0.0 0.0
[3,] 0 0 1 0.0 0.0 0.0
[4,] 0 0 0 0.5 0.0 0.0
[5,] 0 0 0 0.0 0.5 0.0
[6,] 0 0 0 0.0 0.0 0.5
Matrix \(S\) is obtained from matrix \(D\)
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 0 0 0.0000000 0.0000000 0.0000000
[2,] 0 1 0 0.0000000 0.0000000 0.0000000
[3,] 0 0 1 0.0000000 0.0000000 0.0000000
[4,] 0 0 0 0.7071068 0.0000000 0.0000000
[5,] 0 0 0 0.0000000 0.7071068 0.0000000
[6,] 0 0 0 0.0000000 0.0000000 0.7071068
The matrix \(L\) is obtained from the defintion of matrix \(R = L * S\), therefore the matrix \(L = R * S^{-1}\)
[,1] [,2] [,3] [,4] [,5] [,6]
1 1.00 0.0 0.00 0.0 0.0 0
2 0.00 1.0 0.00 0.0 0.0 0
3 0.00 0.0 1.00 0.0 0.0 0
4 0.50 0.5 0.00 1.0 0.0 0
5 0.00 0.5 0.50 0.0 1.0 0
6 0.25 0.5 0.25 0.5 0.5 1
The matrix \(P\) that we used in the simple decomposition, is computed from the relationship \(L^{-1} = I-P\) and from that we get \(P = I - L^{-1}\)
1 2 3 4 5 6
[1,] 0.0 0.0 0.0 0.0 0.0 0
[2,] 0.0 0.0 0.0 0.0 0.0 0
[3,] 0.0 0.0 0.0 0.0 0.0 0
[4,] 0.5 0.5 0.0 0.0 0.0 0
[5,] 0.0 0.5 0.5 0.0 0.0 0
[6,] 0.0 0.0 0.0 0.5 0.5 0
The inbreeding coefficients \(F_i\) for all animals in the pedigree, can also be obtained with pedigreemm
[1] 0.000 0.000 0.000 0.000 0.000 0.125