Function index_table 

pub fn index_table(
    values: Arc<dyn IndexSource>,
    size: usize,
    t: Tolerance,
) -> Result<Table, Error>

A table that reads the index values in values as positions along an axis of length size, as positions reads them. Booleans and integers that all lie inside the axis read in place, each converted as it’s read: the one pass that checks them writes nothing, and also finds whether they give evenly spaced positions, so that a walk can read them as one stride. Floats, read within tolerance t, and values with any outside the axis become the list of positions that positions gives, with the fill position for each value that names none.