Test P/L intersects cases that require robust determinant. See discussion http://trac.osgeo.org/geos/ticket/591
com.vividsolutions.jtstest.geomop.PreparedGeometryOperation
Point on segment between 3rd and 4th vertex of line
POINT(-23.1094689600055 50.5195368635957)
LINESTRING(-23.122057005539 50.5201976774794,-23.1153476966995 50.5133404815199,-23.1094689600055 50.5223376452201,-23.1094689600055 50.5169177629559,-23.0961967920942 50.5330464848094,-23.0887991006034 50.5258515213185,-23.0852302622362 50.5264582238409)
true
Point on the 3rd vertex of line
POINT(-23.1094689600055 50.5223376452201)
LINESTRING(-23.122057005539 50.5201976774794,-23.1153476966995 50.5133404815199,-23.1094689600055 50.5223376452201,-23.1094689600055 50.5169177629559,-23.0961967920942 50.5330464848094,-23.0887991006034 50.5258515213185,-23.0852302622362 50.5264582238409)
true