Memory consumtion
- some memory consumption concerns are tackled in matlab branch
- move fitted out of .nlsur, fitted is huge and only required after final estimation of theta. e.g. should live in nlsur. otherwise if ram can not handle fitted, and it is created at the final stage anyway, it is not helpful either
- try to avoid copying of xi and ri so many times. do it once and afterwards just change the variable order. eg. if casted with cbind the matrix
11 12 21 22
should be converted to
11 12 21 22
if required in rbind.