Rm mono

So this won't actually work, since you're doing `unique()` below. Instead, move this out of the loop. This also allows you to use [a trick](https://github.com/avantcredit/avant-analytics/blob/master/models/prod/default/en-US/2.1.3/helpers.r#L19) to vectorize this double loop, since you have a symmetric matrix, and you would like to drop entries containing a threshold value along the columns. In fact, your code should be identical to that code (cleaned up).

When moving the printing out of the loop, you can do:

```R
if (isTRUE(verbose) && length(inputs$drop_columns) > 0) cat("Dropping ", paste(inputs$drop_columns, collapse = ", "), " due to ....")
``