main/src/georegression/geometry/UtilPolygons2D_F64.java
public static boolean hasAdjacentDuplicates( Polygon2D_F64 polygon , double tol ) {

		for (int i = polygon.vertexes.size()-1,j=0; i >= 0 && polygon.size()>1; j=i,i--) {
			if( polygon.get(i).isIdentical(polygon.get(j),tol)) {
				return true;
			}
		}
		return false;
	}
public static boolean hasAdjacentDuplicates( Polygon2D_F64 polygon , double tol ) {

		for (int i = polygon.vertexes.size()-1,j=0; i >= 0 && polygon.size()>1; j=i,i--) {
			if( polygon.get(i).isIdentical(polygon.get(j),tol)) {
				return true;
			}
		}
		return false;
	}
Remove a point if it's identical to a neighbor

@param polygon The polygon being modified
@param tol Tolerance in radians