Find a reflection of one data frame so that it most closely matches another.
findReflection(df1, df2)A vector of length ncol(df1): Multiplying the first
column of df2 by the first element and multiplying the second
column of df2 by the second element and so on gives the optimal
reflection.
The base data frame.
The data frame that will be reflected across either the x-axis or the y-axis (or both or neither) so that the points in it most closely match df1.