| dt2mat {NMdata} | R Documentation |
Convert a data.table of parameter estimates to a matrix
Description
Often needed when using estimates of Omega or Sigma matrices in further calculations.
Usage
dt2mat(pars, dt.subset = "unique", max.i, fill = 0)
Arguments
pars |
A data.table with parameters. Must contain columns 'i' and 'j' with row and column indexes and 'est' with parameter (matrix) values. |
dt.subset |
Specifies whether pars contains only a lower or upper triangle of an assumed symmetric matrix (most often the case for variance-covariance matrices), or it contains the full matrix. |
max.i |
By default, the maximum row number is derived as he maximum value in the 'i' column. If more (empty ones) are needed, specify the maximum row number with 'max.i'. This can be necessary in cases where only estimated elements are available but a full matrix including elements related to fixed parameters is needed. |
fill |
Value to insert for missing elements |
Details
If pars does not contain all 'i' values, they will be imputed with zeros. The desired matrix dimension is inferred from 'min(i)' and 'max(i)'. In case 'dt.subset=="unique"' missing 'j' elements will also give imputations of missing elements.
Value
a matrix