Function read_gridfm_network 

pub fn read_gridfm_network(
    tables: &GridfmTables,
    scenario: i64,
    base_mva: f64,
    name: &str,
) -> Result<GridfmRead>

Build one Network from in-memory gridfm tables, selecting scenario’s rows. The pure inverse of gridfm_record_batches: base_mva and name come from the caller (the disk path reads them from gridfm_meta.json).

Errors

Error::FormatRead if a required column is missing or mistyped, a column carries nulls, a dense index is negative, or scenario isn’t present; plus whatever Network::validate rejects (duplicate / dangling bus ids).