Description Usage Arguments Value Missing values Examples

Reverse affine transformation.

1 2 | ```
## S3 method for class 'matrix'
backtransformAffine(X, a=NULL, b=NULL, project=FALSE, ...)
``` |

`X` |
An NxK |

`a` |
A scalar, |

`b` |
A scalar, |

`project` |
returned (K values per data point are returned).
If |

`...` |
Not used. |

The "`(X-a)/b`

" backtransformed NxK `matrix`

is returned.
If `project`

is `TRUE`

, an Nx1 `matrix`

is returned, because
all columns are identical anyway.

Missing values remain missing values. If projected, data points that contain missing values are projected without these.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | ```
X <- matrix(1:8, nrow=4, ncol=2)
X[2,2] <- NA
print(X)
# Returns a 4x2 matrix
print(backtransformAffine(X, a=c(1,5)))
# Returns a 4x2 matrix
print(backtransformAffine(X, b=c(1,1/2)))
# Returns a 4x2 matrix
print(backtransformAffine(X, a=matrix(1:4,ncol=1)))
# Returns a 4x2 matrix
print(backtransformAffine(X, a=matrix(1:3,ncol=1)))
# Returns a 4x2 matrix
print(backtransformAffine(X, a=matrix(1:2,ncol=1), b=c(1,2)))
# Returns a 4x1 matrix
print(backtransformAffine(X, b=c(1,1/2), project=TRUE))
# If the columns of X are identical, and a identity
# backtransformation is applied and projected, the
# same matrix is returned.
X <- matrix(1:4, nrow=4, ncol=3)
Y <- backtransformAffine(X, b=c(1,1,1), project=TRUE)
print(X)
print(Y)
stopifnot(sum(X[,1]-Y) <= .Machine$double.eps)
# If the columns of X are identical, and a identity
# backtransformation is applied and projected, the
# same matrix is returned.
X <- matrix(1:4, nrow=4, ncol=3)
X[,2] <- X[,2]*2; X[,3] <- X[,3]*3
print(X)
Y <- backtransformAffine(X, b=c(1,2,3))
print(Y)
Y <- backtransformAffine(X, b=c(1,2,3), project=TRUE)
print(Y)
stopifnot(sum(X[,1]-Y) <= .Machine$double.eps)
``` |

HenrikBengtsson/aroma.light documentation built on Aug. 29, 2019, 6:39 p.m.

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