I have an (5x4) matrix in R, namely data defined as follows:
data <- matrix(rnorm(5*4,mean=0,sd=1), 5, 4)
and I want to create 4 different matrices that follows this formula: Assume that data[,1] = [A1,A2,A3,A4,A5]. I want to create the following matrix:
A1*A1 A1*A2 A1*A3 A1*A4 A1*A5
A2*A1 A2*A2 A2*A3 A2*A4 A2*A5
G1 = A3*A1 A3*A2 A3*A3 A3*A4 A3*A5
A4*A1 A4*A2 A4*A3 A4*A4 A4*A5
A5*A1 A5*A2 A5*A3 A5*A4 A5*A5
Similarly for the other columns i want to calculate at once all the G matrices (G1,G2,G3,G4). How can i achieve that?
results <- lapply(1:ncol(data), function(i) outer(data[, i], data[, i]))
results
[[1]]
[,1] [,2] [,3] [,4] [,5]
[1,] 0.37164 0.37582 0.33424 -0.105387 0.120936
[2,] 0.37582 0.38006 0.33800 -0.106574 0.122298
[3,] 0.33424 0.33800 0.30060 -0.094780 0.108765
[4,] -0.10539 -0.10657 -0.09478 0.029885 -0.034294
[5,] 0.12094 0.12230 0.10876 -0.034294 0.039354
[[2]]
[,1] [,2] [,3] [,4] [,5]
[1,] 0.94684 0.117862 -1.01368 2.01456 0.719629
[2,] 0.11786 0.014671 -0.12618 0.25077 0.089579
[3,] -1.01368 -0.126183 1.08525 -2.15679 -0.770432
[4,] 2.01456 0.250772 -2.15679 4.28633 1.531132
[5,] 0.71963 0.089579 -0.77043 1.53113 0.546941
[[3]]
[,1] [,2] [,3] [,4] [,5]
[1,] 1.61048 0.344159 -0.453466 2.68019 -0.57121
[2,] 0.34416 0.073547 -0.096906 0.57276 -0.12207
[3,] -0.45347 -0.096906 0.127684 -0.75467 0.16084
[4,] 2.68019 0.572758 -0.754669 4.46044 -0.95062
[5,] -0.57121 -0.122068 0.160837 -0.95062 0.20260
[[4]]
[,1] [,2] [,3] [,4] [,5]
[1,] 0.559341 0.859297 0.451096 -0.0522063 -1.027929
[2,] 0.859297 1.320109 0.693004 -0.0802028 -1.579172
[3,] 0.451096 0.693004 0.363799 -0.0421032 -0.829002
[4,] -0.052206 -0.080203 -0.042103 0.0048727 0.095942
[5,] -1.027929 -1.579172 -0.829002 0.0959421 1.889075