x: A NONMEM output object generated using read_nm.
output: A flag specifying the matrix or matrices to be output. Valid flag values are est (the default), se, rse, cor, cse, 95ci, or all.
sigdig: Specifies the number of significant digits to be provided (default=6).
sep: Specifies the separator character to use for 95% confidence intervals (default="-").
est.step: Specifies which estimation step to return parameters from (default is the last).
Returns
A symmetrical matrix, or a list of symmetrical matrices if all is specified.
est returns the estimated SIGMA variance-covariance matrix. se returns the standard errors for the estimated SIGMA variance-covariance matrix. rse returns the relative standard errors for the estimated SIGMA variance-covariance matrix (se/est100). cor returns the correlation matrix matrix. cse returns the standard errors for the correlation matrix. 95ci returns the asymptotic 95% confidence intervals for the elements of the SIGMA variance-covariance matrix (est +/- 1.96se). all returns all available SIGMA matrices.