[amelia] How to code the case priors matrix in Amelia for R

Hi all, I am working on a Mac and hence can't use Amelia View. For configuration ease, I set up the configuration for an imputation routine with Amelia View on an old Windows laptop which is now powerful enough for the calculation. Hence, I need to adapt the R archive file to run it on my Mac. When I look into the R archive file created by Amlia View, I wonder how the case priors (the similarity matrix between cases) are coded for to be understood by Amelia. R lets you transform a vector into a matrix by indicating the vector, number of lines and columns. With my 64 cases (cross-sectional units), this should produce a vector with the length of 64*64=4096. Amelia View displays only half of the matrix of n*(n-1)/2 (if I am not mistaken) to avoid redundancy. How are the redundant fields coded (do they receive a 0 and Amelia knows that they are redundant values?)? What made me struggle was that the vector created by Amelia View is too short to represent the n^2 matrix (it was around 4014 instead of the 4096 in length and had a few bizarre non integers at the end). So the question, how does one code the case priors matrix in a R script? For the priors there is no ambiguity since they consists of a n*n and not of a n*(n-1)/2 matrix. I have on additional question: how does one indicate in the R script that the output is to be written as a .dta ? Thanks for your help, Raffael __________________________________ Raffael Himmelsbach Institut d'Etudes Politiques et Internationales Batiment Anthropôle, Bureau 5128 Université de Lausanne CH-1015 Lausanne Phone: +41 21 692 31 76 Cell: +41 79 756 85 10