Join dots with lines and intersect

#LinesToDraw is the pandas series where we have our dots stored.
#Input_High and Input_Low are pandas series where we have our highs and lows of the candlesticks stored.


#Function to find the value of all the points of a line
def FindYGivenIndex(i,index,Y,subindex,subY):
    return Y+(i-index)*(subY-Y)/(subindex-index)

LineDots = list() #I will store a list of lines (with each dot in that line) here.

#Now we calculate the possible existing lines, and store each into a series:

for index in LinesToDraw.index:
    Y = LinesToDraw.ix[index]

    for subindex in LinesToDraw.index:
        subY = LinesToDraw.ix[subindex]

        if subindex > index and abs(subindex - index)<30 and abs(subindex - index)>3:

            LineDots.append( pd.DataFrame(range(index,subindex),index = range(index,subindex)).apply(FindYGivenIndex,args = (index,Y,subindex,subY,)) )

CurrentPlot.LineDots = LineDots
CurrentPlot.LinesToDraw = list()

#Now for the resulting lines, we filter the ones that are over or under Input_High or Input_Low

for line in CurrentPlot.LineDots:
    if len(line.dropna()):
        try:
            if (Input_High.ix[line.index].astype('float') <= line.iloc[:,0].astype('float')).all() or (Input_Low.ix[line.index].astype('float') >= line.iloc[:,0].astype('float')).all():
                CurrentPlot.LinesToDraw.append(line)
        except:
            pass
#Now we can draw them, but as said, we iterated too many times, making the process _very_ slow.

for line in CurrentPlot.LinesToDraw:
    plot([CurrentPlot.X_Axis.ix[line.index[0]],CurrentPlot.X_Axis.ix[line.index[-1]]], [line.iloc[0],line.iloc[-1]], 'k-')