Rollers = [{} for i in range(num_rollers)]  # declare the rollers
Rollers[0] = {'top_seg': 0, 'segments': 84, 'material': Copper, 'direction': ACW, 'ink': []} # Transfer
Rollers[1] = {'top_seg': 0, 'segments': 71, 'material': Rubber, 'direction': CW, 'ink': []}  # Inking
Rollers[2] = {'top_seg': 0, 'segments': 84, 'material': Copper, 'direction': ACW, 'ink': []}
Rollers[3] = {'top_seg': 0, 'segments': 75, 'material': Rubber, 'direction': CW, 'ink': []}
Rollers[4] = {'top_seg': 0, 'segments': 84, 'material': Copper, 'direction': ACW, 'ink': []} # Ink drum

for i in range(0,num_rollers): # update the dictionary
    for j in range(Rollers[i]['segments']):
        Rollers[i]['ink'].append(0)

Nips = [{} for i in range(num_nips)]    # declare the nip locations
Nips[0] = {'rollers': [0, 1], 'locations': []}
Nips[1] = {'rollers': [1, 2], 'locations': []}
Nips[2] = {'rollers': [2, 3], 'locations': []}
Nips[3] = {'rollers': [3, 4], 'locations': []}

def refresh (): # function to move the nips as the rollers turn
    Nips[0]['locations'] = [(Rollers[0]['top_seg'] + 71)  % Rollers[0]['segments'], (Rollers[1]['top_seg'] + 25)  % Rollers[1]['segments']]
    Nips[1]['locations'] = [(Rollers[1]['top_seg'] + 46)  % Rollers[1]['segments'], (Rollers[2]['top_seg'] + 12)  % Rollers[2]['segments']]
    Nips[2]['locations'] = [(Rollers[2]['top_seg'] + 44)  % Rollers[2]['segments'], (Rollers[3]['top_seg'] + 1)  % Rollers[3]['segments']]
    Nips[3]['locations'] = [(Rollers[3]['top_seg'] + 52)  % Rollers[3]['segments'], (Rollers[4]['top_seg'] + 17)  % Rollers[4]['segments']]


def turn ():    # turn the rollers, refresh the nips
    for R in Rollers:
        R['top_seg'] = (R['top_seg'] + R['direction']) % R['segments']

    refresh()

def ink ():
    for N in Nips:
        total_ink = 0
        for R in range(2):
            Roller = Rollers[N['rollers'][R]]
            location = N['locations'][R]
            total_ink = total_ink + Roller['ink'][location]
        for R in range(2):
            Roller = Rollers[N['rollers'][R]]
            location = N['locations'][R]

        # Assuming that ink split is dictated only by material
            if Roller['material']:
               Roller['ink'][location] = ratio*total_ink
            else:
               Roller['ink'][location] = (1-ratio)*total_ink

Rollers[0]['ink'][0] = 25

for i in range(360):
    turn()
    ink()

sum = 0
for i in Rollers[4]['ink']:
    sum = sum + i
mean = sum/Rollers[4]['segments']

temp = 0
for i in Rollers[4]['ink']:
    temp = temp + (i-mean)*(i-mean)

sdev2 = temp/Rollers[4]['segments']

sdev = sdev2**0.5

# Results
RollerOut = open('RollerOut.csv', 'w') # creates a workbook in excel
for row in Rollers:
    for column in row:
        RollerOut.write('%s,' % column) # writes strings to columns rather than rows
    RollerOut.write('n') # writes values from Rollers
RollerOut.close()
print Rollers[4]
print 'mean ink thickness on plate = ', mean
print 'sdev of ink thickness on plate= ', sdev

def roll_data():
    roll_diameter = float(raw_input("Enter roller diameter" + str(i) + ": "))
    seg_angle = -1
    while seg_angle < 0 or seg_angle >360:
        print "anti-clockwise from TDC"
                  seg_angle = float(raw_input("Enter angle into nip" = str(i) + ": "))
        if (seg_angle <0 or seg_angle>360):
            print "invalid range"
R = Rollers[i]
R['segments'] = int(round(Rollers[4]['segments']*roll_diameter/plate_diameter))
R['angle'] = (360/R['segments']) # angle in degrees
# R['radians'] = (R['angle']*(pi/180) # angle in radians