Fixes loadings \(\ell_{\cdot k}\) or factors \(f_{\cdot k}\)
for one or more factor/loadings pairs, so that their values are not
updated during subsequent backfits. For a given pair, either the loadings
or factor can be fixed, but not both, and either all entries or a subset
can be fixed. To unfix, use function flash_factors_unfix. See
flash_factors_init for an example of usage.
flash_factors_fix(
flash,
kset,
which_dim = c("factors", "loadings"),
fixed_idx = NULL,
use_fixed_in_ebnm = NULL
)A flash or flash_fit object.
A vector of integers indexing the factor/loadings pairs whose loadings or factors are to be fixed.
Whether to fix factors or loadings.
If fixed_idx = NULL, then all loadings or factor
values will be fixed. If only a subset are to be fixed,
then fixed_idx should be an appropriately-sized vector or
matrix of values that can be coerced to logical. For example, if
a subset of loadings for two factor/loadings pairs are to be fixed, then
fixed_idx should be a length-\(n\) vector or an \(n\) by 2
matrix (where \(n\) is the number of rows in the data matrix).
By default, fixed elements are ignored when
solving the EBNM subproblem in order to estimate the prior \(\hat{g}\).
This behavior can be changed by setting use_fixed_in_ebnm = TRUE.
This is a global setting which applies to all factor/loadings pairs;
behavior cannot vary from one factor/loadings pair to another.
The flash object from argument flash, with
factors or loadings fixed as specified.