Finding line is self intersected or not using PyQGIS

Question

I have to find whether the line feature is self intersected or not.

I have tried the below logic but I am not getting it.

Is there a way to find the solution?

    lineLayerName=self.lineLayer.name()
    for ft in self.lineLayer.getFeatures():
        if ft.geometry().intersects(ft.geometry()):
            gem = ft.geometry().intersection(ft.geometry())
            intPt=gem.asPoint()
            if intPt.x() != 0 and intPt.y() != 0:
                print "Self-intersected"

If the line is self-intersected means I need the intersected point. I have attached the screenshot for reference.

Answer 1

QgsGeometry has the isSimple() function that will return False for a line that self intersects.

lineLayerName=self.lineLayer.name()
for ft in self.lineLayer.getFeatures():
    if not ft.geometry().isSimple():
        print "Not simple - self-intersect"