This function is used to write a 4x4 numeric matrix representing an affine
transformation to a file. A comment is also (optionally) written, which
specifies the matrix as using the NiftyReg convention, for the benefit of
readAffine.
Usage
writeAffine(affine, fileName, comments = TRUE)
Arguments
affine
A 4x4 affine matrix.
fileName
A string giving the file name to write the matrix to.
comments
Logical value: if TRUE comments are written to the
file in lines beginning with #.