public int getRow(V v) {
		if (!rowsByVertex.containsKey(v)) {
			throw new IllegalArgumentException("Vertex is not in row: " + v);
		}
		return rowsByVertex.get(v);
	}
The grid index of this column (0, 1...n) for the number of columns
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/Column.java