Changing fontsize in python subplots

Question

I have made a phase plot of a bistable stable, with the nulclines on the main graph and have added a subplot with the trajectories overlaying it. However, no matter what I try, I cannot seem to get the x and y labels to increase in font size to 20.

Any help would be greatly appreciated.

Although there are similar questions, the answers to said queries don't seem to apply to this particular problem.

Thanks again!

import numpy as np
from scipy.integrate import odeint
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid.axislines import SubplotZero
from matplotlib import pylab
from pylab import linspace
from numpy import meshgrid
from numpy import hypot


a1 = 1.0 #(Rate constant)
g1 = 4.0 # Hill number for cdc2
b1 = 200.0 # Rate Constant
k1 = 30.0 #Michaelis Constant
v =1 #coefficient that reflects the strangth of the influence of Wee1 on Cdc2
a2 = 1.0# Rate Constant
g2 = 4.0 #Hill number for Wee1
b2 = 10.0 # Rate Constant
k2 = 1.0# Michaelis constant

# Function for calculating the phase plot
def Function(u,t=0,mu=.1):
    x1 = u[0]
    y1 = u[1]
    dv = (a2* (1.0 - y1) - (b2 * y1 * x1**g2) /(k2 + (x1**g2)))                 # Model of Cdc2
    dx = (a1* (1.0 - x1) - (b1 * x1 * ((v * y1)**g1)) / (k1 + ((v*y1) **g1)))  # Model of Wee1
    return (dx,dv)

t = linspace(0,1,1) #Return list from 0 to 1 in 25 intervals
u0 = np.array([1,1]) # Creates array for odeint function 


mu = [1,10] #call mu for 2
for m in mu:#Get u (differentiation function )
    u = odeint(Function,u0,t,args=(m,))
#   ax.plot(u[0:,0],u[0:,1])
x = linspace(0,1,17) #Creates values for x
y = linspace(0,1,18)#Creates values for y to plot
x,y = meshgrid(x,y)# creates a grid of x by y
X,Y = Function([x,y])# Applies funciton to grid
M = (hypot(X,Y))# Get hypotenuse of X by Y
X,Y = X/M, Y/M# Calculate length(strength) of arrows


#Calculate Nulclines-----------------------------------------------------------

Nulclinevalues = np.arange(0, 1+0.001, 0.001)#Calulate values to set nulcineto
NulclineXX = []# set to an array
NulclineYY = []#set to an array
 # Following 2 formulas show the calculation fo the nullclines
def calcnulclineyy(xx1): 
    oa2 = 1.0#RAte constant
    og2 = 4.0 #Hill number for Wee1
    ob2 = 10.0#Rate constant
    ok2 = 1.0#Michaelis constant
    YY = (oa2*((xx1)**og2) + ok2) / (oa2*((xx1**og2)+ok2)+(ob2*(xx1**og2)))

return YY



def calcnulclinexx(yy1):
    oa1 = 1.0 #Rate constant 
    og1 = 4.0 # Hill number for cdc2 
    ob1 = 200.0 #Rate constant
    ok1 = 30.0#Michaelis constant
    ov = 1##coefficient that reflects the strength of the influence of Wee1 on Cdc2
    og2 = 4.0 #Hill number for Wee1
    XX = (oa1*(ok1+(ov*yy1)**og2)) / (oa1*(ok1+(ov*yy1)**og1)+ob1*(ov*yy1)**og1)

return XX

for YY in Nulclinevalues: 
    # print Y
    NulclineXX.append(calcnulclinexx(YY))

for XX in Nulclinevalues:
    #Print X
    NulclineYY.append(calcnulclineyy(XX))


fig = plt.figure(figsize=(6,6)) # 6x6 image

ax = SubplotZero(fig,111,) #Plot arrows over figure

fig.add_subplot(ax) # Plot arrows over figure

# Plot both nulcines on same graph

plt.axis((0,1,0,1))
ax.set_title('v = 1',fontweight="bold", size=20) # Title
ax.set_ylabel('Active Wee1', fontsize = 20.0) # Y label
ax.set_xlabel('Active Cdc2-cyclin B', fontsize = 20) # X label
plt.plot (NulclineXX,Nulclinevalues, label = " Cdc2 nulcline",c = 'r', linewidth = '2')
plt.plot (Nulclinevalues,NulclineYY, label = "Wee1 nulcline",c = '#FF8C00', linewidth = '2')

ax.quiver(x,y,X,Y,M) # plot quiver plot on graph
ax.grid(True) # Show major ticks    
ax.legend(handletextpad=0,loc='upper right') # Plot legend

plt.show() # Show plot

Answer 1

Here are the changes I made to the last bit of your code:

fig = plt.figure(figsize=(6,6)) # 6x6 image

ax = plt.gca()       #SubplotZero(fig,111,) #Plot arrows over figure

#fig.add_subplot(ax) # Plot arrows over figure

# Plot both nulcines on same graph

plt.axis((0,1,0,1))
ax.set_title('v = 1',fontweight="bold", size=20) # Title
ax.set_ylabel('Active Wee1', fontsize = 20.0) # Y label
ax.set_xlabel('Active Cdc2-cyclin B', fontsize = 20) # X label
plt.plot (NulclineXX,Nulclinevalues, label = " Cdc2 nulcline",c = 'r')
plt.plot (Nulclinevalues,NulclineYY, label = "Wee1 nulcline",c = '#FF8C00')

ax.quiver(x,y,X,Y,M) # plot quiver plot on graph
ax.grid(True) # Show major ticks    
ax.legend(handletextpad=0,loc='upper right') # Plot legend

plt.show() # Show plot

I changed the way you defined ax, and removed the call adding it to the figure. (I also did 2 other changes that you probably don't need - for some reason my installation didn't like the linewidth instructions when I tried to show it, so I took them out - it looks like something wrong with my installation).