upper or lower triangle or all values of a matrix as long-format
mat2dt(x, triangle = "lower", as.fun)A matrix
Either `"lower"` (default) or `"upper"`, or `"all"` for which triangle to return. `"lower"` and `"upper"` are equivalent for covariance or correlation matrices but the returned indexes will differ. `"all"` will return the full matrix which mostly makes sense if matrix is not a covariance or correlation matrix.
See `?NMdataConf`
A `data.frame`-like object with indexes `i` and `j` for position and matrix element value in `value` column.
The matrix is assumed ordered and the index numbers for rows and columns will be returned in `i` and `j` columns. Row names and column names will be returned in columns `parameter.i` and `parameter.j`.
dt2mat