add method
Add v under key id. Dim must match dim.
Implementation
void add(Object? id, Vector v) {
if (v.dim != dim) {
throw StateError(
'FlatIndex.add: vector dim ${v.dim} != index dim $dim',
);
}
final n = _ids.length;
final needed = (n + 1) * dim;
if (_data.length < needed) {
// Grow geometrically, minimum 16 rows.
final newRows = math.max(n * 2, 16);
final grown = Float32List(newRows * dim);
grown.setRange(0, n * dim, _data);
_data = grown;
}
_data.setRange(n * dim, (n + 1) * dim, v.values);
_ids.add(id);
}