Saturday, September 24, 2016

Cleaner Code

In light of Gene Callahan's comment yesterday, I have posted some cleaner code below. Those who are not programmers may not understand the process of passing objects through multiple methods (i.e., "plotLines (. . .)). If you don't get it, don't worry about it. Those who prefer tighter organization should use this code.


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from __future__ import print_function
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.backends.backend_pdf import PdfPages

pp = PdfPages('SupplyAndDemandFloor.pdf')
def supplyAndDemandFloor(supply, demand, floor, equilibrium):
    
    fig = plt.figure(dpi=128, figsize=(10,6))
    plotLines(supply, demand, equilibrium, floor)        
    frame = plt.gca()        
    plt.title('Pizza Market', fontsize = 32)
    placeText()
    setupAxes(frame)  
    pp.savefig(fig)
    pp.close()

def placeText():
    #plt.text(x,y,text,fontsize)
    plt.text(-500, 10000, "$p$", fontsize=24)
    plt.text(-550, 7900, "$p_s$", fontsize=24)
    plt.text(-550, 5000, "$p_e$", fontsize=24)
    plt.text(8200, 8800,"$S$", fontsize = 24)
    plt.text(8200, 2000,"$D$", fontsize = 24)
    plt.text(1800, -650, "$Q_d$", fontsize=24)
    plt.text(7800, -650, "$Q_s$", fontsize=24)
    plt.text(4800, -650, "$Q_e$", fontsize=24)
    plt.text(10000, -650, "$Q$", fontsize=24)

def plotLines(supply, demand, equilibrium, floor):
    # plt.plot((x1,x2), (y1,y2), linestyle/color, linewidth)
    plt.plot((2000, 2000), (0, 8000), 'r--', linewidth=1.5)  
    plt.plot((8000, 8000), (0, 8000), 'r--', linewidth=1.5)  
    plt.plot((5000, 5000), (0, 5000), 'k--', linewidth=1.5)      
    plt.plot(supply,  'k-', linewidth=3)
    plt.plot(demand, 'k-', linewidth=3)
    plt.plot(equilibrium, 'k--', linewidth=1.5)
    plt.plot(floor, 'r--',label= "Price Floor", linewidth=1.5)

def setupAxes(frame):
    frame.axes.get_xaxis().set_visible(False)
    frame.axes.get_yaxis().set_visible(False)
    plt.xlabel("Labor", fontsize=20)
    plt.ylabel("Wage", fontsize = 20)
    plt.tick_params(axis='both', which='major', labelsize=16)

Supply = np.arange(10000)
Demand = np.arange(10000,0, -1)
priceFloor = np.arange(1, 10000)
priceFloor[priceFloor > 0] = 8000
priceEquilibrium = np.arange(1, 5000)
priceEquilibrium[priceEquilibrium > 0] = 5000
supplyAndDemandFloor(Supply, Demand, priceFloor, priceEquilibrium)

Friday, September 23, 2016

Building Supply and Demand Graphs in Python

When I first started teaching, I grew frustrated with the process of creating visualizations. Microsoft office graphs look tacky. I wanted something that is can be standardized for making graphs of supply and demand. I also wanted it to be customizable and not be corrupted by the name of the company that provided the means for creating the graph (see here). After having used Python and the matplot library to make other visualizations, I realized that I could use similar code for making a generic supply and demand graph. You can customize Matplotlib's graphs to a significant degree.



If you are afraid of programming, never fear. This is a great place to start. Just download Anaconda and use this template. The code below is filled with notes to help you fill out the template. The final graph is depicted above:
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from __future__ import print_function
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.backends.backend_pdf import PdfPages

pp = PdfPages('LaborSupplyAndDemandFloor.pdf')

# "supply", "demand", "floor" and "equilibrium" are all numpy arrays
# created at the bottom of the script.
# the supplyAndDemandFloor method is also called at the bottom of the script
def supplyAndDemandFloor(supply, demand, floor, equilibrium):
    
    fig = plt.figure(dpi=128, figsize=(10,6))

    # Plot supply and demand curves
    # Must instantiate numpy arrays -- see lines 85 and 87
    plt.plot(supply,  'k-', linewidth=3)
    plt.plot(demand, 'k-', linewidth=3)

    # The length of the equilibrium line must match the horizontal coordinate 
    # of the equilibrium quanity -- see lines 98, 100
    plt.plot(equilibrium, 'k--', linewidth=1.5)
    # The floor is a horizontal line -- see lines 90, 94
    plt.plot(floor, 'r--',label= "Price Floor", linewidth=1.5)

    # plt plt takes the form like:
    # plt.plot((x1,x2)),(y1,y2), 'r-', linewidth = x)
    
    # e.g., for command on line ##:
    # create a vertical line at x1 = 2000, y2 = 2000, y1 = 0, y2 = 8000
    plt.plot((2000, 2000), (0, 8000), 'r--', linewidth=1.5)
    plt.plot((8000, 8000), (0, 8000), 'r--', linewidth=1.5)  
    plt.plot((5000, 5000), (0, 5000), 'k--', linewidth=1.5)      

    # frame = plt.gca() required to use commands for removing
    # values on axes        
    frame = plt.gca()    
    
    # remove axis values
    frame.axes.get_xaxis().set_visible(False)
    frame.axes.get_yaxis().set_visible(False)    

    plt.title('Pizza Market', fontsize = 32)
    
    # p variable on top of y-axis
    plt.text(-500, 10000, "$p$", fontsize=24)

    # surplus price variable
    plt.text(-550, 7900, "$p_s$", fontsize=24)
    
    # equilibrium price variable
    plt.text(-550, 5000, "$p_e$", fontsize=24)

    # identify supply curve    
    plt.text(8200, 9000,"$S_p$", fontsize = 24)
    # identify demand curve    
    plt.text(8200, 2000,"$D_p$", fontsize = 24)
    

    # quantity demanded at surplu price
    plt.text(1800, -650, "$Q_d$", fontsize=24)
    # quantity supplied at surplus price
    plt.text(7800, -650, "$Q_s$", fontsize=24)
    # Qs = Qd at equilibrium price
    plt.text(4800, -650, "$Q_e$", fontsize=24)
    # mark that Q is represented on horizontal axis
    plt.text(10000, -650, "$Q$", fontsize=24)

    # label the axes
    plt.xlabel("Pizza", fontsize=20)
    plt.ylabel("Price", fontsize = 20)
    plt.tick_params(axis='both', which='major', labelsize=16)
#    plt.legend(floor, loc='upper right')
    
    # save PDF of figure
    # you can also save to image file
    # pdf is useful if multiple graphs are created
    pp.savefig(fig)
    
    # close PDF
    pp.close()
    

# Instantiate array with supply curve points
supply = np.arange(10000)
# ... demand curve points
demand = np.arange(10000,0, -1)

# ... for price floor line
priceFloor = np.arange(1, 10000)
# set value of all points value of price floor
# value of prices are arbitrary since we dropped
# axis values
priceFloor[priceFloor > 0] = 8000

# ... for equilibrium price, length of this array 
# is equal to the equilibrium quantity
priceEquilibrium = np.arange(1, 5000)
# set all values to the equilibrium price
priceEquilibrium[priceEquilibrium > 0] = 5000

# finally, call method to produce the graph
supplyAndDemandFloor(supply,demand, priceFloor, priceEquilibrium)

Thursday, September 1, 2016

How to Succinctly Visualize the BehaviorSpace from NetLogo using Python

When I first programmed a heuristic rendition of Sugarcape, I was impressed by the results. Time and again, they were consistent across the behavior-space. But how does one convey results that take many hours to observe into simple visualizations? Is it possible to condense the data in such a manner?

First, I needed to generate data that could be read easily by Python. NetLogo's standard data generator does not do this well. Here is the code that I used instead:

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to setup
. . . 
  prep-csv-name
  reset-ticks
end

. . . 

to go
. . . 
  write-csv csv-name final-output
  tick
end

. . . 

to prepare-behavior-space-output
  set final-output (list
    total-sugar
    total-water
    mean-price-current-tick
    price-variance
    population
    
    basic-only
    basic-herder
    basic-arbitrageur
    basic-herder-arbitrageur
    switcher-only
    switcher-herder
    switcher-arbitrageur
    switcher-herder-arbitrageur

    current-percent-basic
    current-percent-arbitrageur
    current-percent-herder
    current-percent-switcher
    wealth-basic-only
    wealth-basic-herder
    wealth-basic-arbitrageur
    wealth-basic-herder-arbitrageur
    wealth-switcher-only
    wealth-switcher-herder
    wealth-switcher-arbitrageur
    wealth-switcher-herder-arbitrageur
    sugar-consumed-this-tick
    water-consumed-this-tick
    distance-from-equilibrium-price
    mean-price-50-tick-average
    mean [endogenous-rate-of-price-change] of turtles
    )
end

to write-csv [ #filename #items ]
  ;; #items is a list of the data (or headers!) to write.
  if is-list? #items and not empty? #items
  [ file-open #filename
    ;; quote non-numeric items
    set #items map quote #items
    ;; print the items
    ;; if only one item, print it.
    ifelse length #items = 1 [ file-print first #items ]
    [file-print reduce [ (word ?1 "," ?2) ] #items]
    ;; close-up
    file-close
  ]
end

to prep-csv-name
  set csv-name "ssugarscapeLocalTradeAllClassesFinal.csv"
  set csv-name replace-item 0 csv-name (word behaviorspace-run-number)
end

to-report quote [ #thing ]
  ifelse is-number? #thing
  [ report #thing ]
  [ report (word "\"" #thing "\"") ]
end

This creates csvs for each run that print out the value of objects described in and in the order presented in the list. This order is important as the same ordering is used in Python when I collect data from the csvs.

The setup looked like this:


[Late Add] I used 8 different settings for sugar and water metabolism. this is reflected in the python code under "num_x" and "num_y". 64 settings were used. Each setting was run 10 times to produce 640 runs, each of whose length were 15000 periods.

Below is the Python code that I used to generate visualizations that look like this (which were used in this article):

Each column and row show a pair of values representing the rate of consumption for each by the agents. In this case, I was capturing the change in wealth per capita, defined as units of time the agent can survive given his current stock of goods. "initialize_image(num_x, num_y):" and "color_points(title, filename, category, mean_values,pp, tick, min_val, max_val):" are the methods that generalize the output.

Please note that this code will fail if the size of your data set is too large to be held by your RAM. In that case, you will need to use the dask library to instantiate the dataframes held by the elements in the "runs" and/or "mean_values" dataframes.

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from __future__ import print_function
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
import pandas as pd
from matplotlib.backends.backend_pdf import PdfPages

files = 640
ticks = 15000
run_period = []
#np.empty((ticks))
num_x = 8
num_y = 8
runs_per_setting = 10

for j in range(0, ticks):
 run_period.insert(j, j + 1)
run_period = pd.Series(run_period)
def prepare_lists(files):

#    # number of elements recorded in csv by netlogo
    num_categories = 30

#    # number of elements created using data from netlogo
    additional_categories = 16
    total_categories = num_categories + additional_categories
    runs = pd.Series([np.arange(files)])    
    names = pd.Series(['sugar', 
                   'water',
                   'mean_price',
                   'price_variance',
                   'population', 
                   'basic_only',
                   'basic_herder',
                   'basic_arbitrageur', 
                   'basic_herder_arbitrageur', 
                   'switcher_only', 
                   'switcher_herder', 
                   'switcher_arbitrageur', 
                   'switcher_herder_arbitrageur', 
                   'percent_basic',
                   'percent_arbitrageur', 
                   'percent_herder', 
                   'percent_switcher', 
                   'basic_only_wealth',
                   'basic_herder_wealth',
                   'basic_arbitrageur_wealth',
                   'basic_herder_arbitrageur_wealth',
                   'switcher_only_wealth',
                   'switcher_herder_wealth',
                   'switcher_arbitrageur_wealth',
                   'switcher_herder_arbitrageur_wealth', 
                   'sugar_flow', 
                   'water_flow',
                   'distance_from_equilibrium_price',
                   'fifty_period_RAP', 
                   'mean_rate_of_price_change'])

    names_dict = {'sugar': [np.arange(ticks)], 
             'water': [np.arange(ticks)],
             'mean_price': [np.arange(ticks)], 
             'price_variance': [np.arange(ticks)],
             'population': [np.arange(ticks)],
             'basic_only': [np.arange(ticks)], 
             'basic_herder': [np.arange(ticks)],
             'basic_arbitrageur': [np.arange(ticks)],
             'basic_herder_arbitrageur': [np.arange(ticks)],
             'switcher_only': [np.arange(ticks)],
             'switcher_herder': [np.arange(ticks)],
             'switcher_arbitrageur': [np.arange(ticks)],
             'switcher_herder_arbitrageur': [np.arange(ticks)],
             'percent_basic': [np.arange(ticks)],
             'percent_arbitrageur': [np.arange(ticks)],
             'percent_herder': [np.arange(ticks)], 
             'percent_switcher': [np.arange(ticks)],
             'basic_only_wealth': [np.arange(ticks)],
             'basic_herder_wealth': [np.arange(ticks)],
             'basic_arbitrageur_wealth': [np.arange(ticks)],
             'basic_herder_arbitrageur_wealth': [np.arange(ticks)],
             'switcher_only_wealth': [np.arange(ticks)],
             'switcher_herder_wealth': [np.arange(ticks)],
             'switcher_arbitrageur_wealth': [np.arange(ticks)],
             'switcher_herder_arbitrageur_wealth': [np.arange(ticks)], 
             'sugar_flow': [np.arange(ticks)],
             'water_flow': [np.arange(ticks)],
             'distance_from_equilibrium_price': [np.arange(ticks)],
             'fifty_period_RAP': [np.arange(ticks)], 


            # Categories to be generated within python             
             'basic_only_wealth_per_capita': [np.arange(ticks)],
             'basic_herder_wealth_per_capita': [np.arange(ticks)],
             'basic_arbitrageur_wealth_per_capita': [np.arange(ticks)],
             'basic_herder_arbitrageur_wealth_per_capita': [np.arange(ticks)],
             'switcher_only_wealth_per_capita': [np.arange(ticks)],
             'switcher_herder_wealth_per_capita': [np.arange(ticks)],
             'switcher_arbitrageur_wealth_per_capita': [np.arange(ticks)],
             'switcher_herder_arbitrageur_wealth_per_capita': [np.arange(ticks)],             
             'percent_basic_only': [np.arange(ticks)],
             'percent_basic_herder': [np.arange(ticks)],
             'percent_basic_arbitraguer': [np.arange(ticks)],
             'percent_basic_herder_arbitraguer': [np.arange(ticks)],
             'percent_switcher_only': [np.arange(ticks)],
             'percent_switcher_herder': [np.arange(ticks)],
             'percent_switcher_arbitraguer': [np.arange(ticks)],
             'percent_switcher_herder_arbitraguer': [np.arange(ticks)],


            }
    for i  in range(1, files + 1):
        filename = str(i) + 'sugarscapeLocalTradeBasics.csv'
        runs[i] = pd.read_csv(filename, names = names)
#        , sep = None,engine='python')

        # Add categories generated from data manipulation
        runs[i]['basic_only_wealth_per_capita'] = runs[i]['basic_only_wealth'] / runs[i]['basic_only']
        runs[i]['basic_herder_wealth_per_capita'] = runs[i]['basic_herder_wealth'] / runs[i]['basic_herder']        
        runs[i]['basic_arbitrageur_wealth_per_capita'] = runs[i]['basic_arbitrageur_wealth'] / runs[i]['basic_arbitrageur']
        runs[i]['basic_herder_arbitrageur_wealth_per_capita'] = runs[i]['basic_herder_arbitrageur_wealth'] / runs[i]['basic_herder_arbitrageur']
        runs[i]['switcher_only_wealth_per_capita'] = runs[i]['switcher_only_wealth'] / runs[i]['switcher_only']
        runs[i]['switcher_herder_wealth_per_capita'] = runs[i]['switcher_herder_wealth'] / runs[i]['switcher_herder']        
        runs[i]['switcher_arbitrageur_wealth_per_capita'] = runs[i]['switcher_arbitrageur_wealth'] / runs[i]['switcher_arbitrageur']
        runs[i]['switcher_herder_arbitrageur_wealth_per_capita'] = runs[i]['switcher_herder_arbitrageur_wealth'] / runs[i]['switcher_herder_arbitrageur']
        runs[i]['percent_basic_only'] =  runs[i]['basic_only'] / runs[i]['population']
        runs[i]['percent_basic_herder'] =  runs[i]['basic_herder'] / runs[i]['population']
        runs[i]['percent_basic_arbitrageur'] = runs[i]['basic_arbitrageur'] / runs[i]['population']
        runs[i]['percent_basic_herder_arbitrageur'] = runs[i]['basic_herder_arbitrageur'] / runs[i]['population']
        runs[i]['percent_switcher_only'] = runs[i]['switcher_only'] / runs[i]['population']
        runs[i]['percent_switcher_herder'] =  runs[i]['switcher_herder']  / runs[i]['population'] 
        runs[i]['percent_switcher_arbitrageur'] = runs[i]['switcher_arbitrageur']  / runs[i]['population']
        runs[i]['percent_switcher_herder_arbitrageur'] =  runs[i]['switcher_herder_arbitrageur']  / runs[i]['population']
        
        # Keep track of run # processesed
        print(i)

    # will be used to record mean parameter values for particular settings 
    # across the behavior space
    mean_values = pd.DataFrame(columns = [np.arange(num_x)], index = [np.arange(num_y)])
    
#    run_name = np.empty((num_x, num_y, runs_per_setting), dtype = np.dtype((str,32))) 
    for x in range(0,num_x):
        for y in range(0,num_y):
            
            mean_values[x][y] = pd.DataFrame(names_dict)
    
    for x in range(0,num_x):
        for y in range(0,num_y ):
            for z in range(0,runs_per_setting):
                # Add 1 because file index starts at 1
            
#                run_name[x][y][z] = 'Cs = ' + str(.5 + x * .025) + ' Cw = ' + str(.5 + y * .025) + ' run ' + str(z + 1) + ' of ' + str(runs_per_setting)
                run_number = x * num_y * runs_per_setting + y * runs_per_setting + z + 1
                
                mean_values[x][y] = mean_values[x][y].add(runs[run_number], fill_value=0)
                
            print("processing: " + str(run_number))
    mean_values = mean_values / runs_per_setting
    print_behavior_space_representation(mean_values)
            
##############################################################################################                        
##############################################################################################



def initialize_image(num_x, num_y):
 image = []
 for i in range(num_y):
  x_colors = []
  for j in range(num_x):
   x_colors.append(0)
  image.append(x_colors)
 return image


def color_points(title, filename, category, mean_values,pp, tick, min_val, max_val):
    image = initialize_image(num_x, num_y)
    
    for i in range(0, num_x):
        for j in range(0, num_y):
            image[i][j] = mean_values[i][j].iloc[tick][category]
    print(image)        
    plt.imshow(image, origin='lower', extent=(.45, .8,  .45, .8),
               cmap=cm.Greys_r, interpolation = 'nearest')
    plt.colorbar()
    plt.clim(min_val, max_val)
    plt.xlabel('Water Consumption Rate')
    plt.ylabel('Sugar Consumption Rate')
    plt.title(title + " Period " +  str(tick + 1))
    fig = plt.gcf()
    plt.show()
    plt.draw()
    pp.savefig(fig)


def print_behavior_space_representation(data):  
    interval = 500
    pp = PdfPages('population_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Population\nLocal Trade Basics","Population Local Trade Basics", "population", data, pp, q,250,1800)
    plt.close('all')
    pp.close()

    pp = PdfPages('PV_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Price Variance\nLocal Trade Basics", "Price Variance Local Trade Basics", "price_variance", data, pp, q,0 , 8)
    plt.close('all')
    pp.close()

    pp = PdfPages('MP_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Mean Price (Logged)\nLocal Trade Basics","Mean Price Local Trade Basics", "mean_price", data, pp, q, -1, 8)
    plt.close('all')
    pp.close()

    pp = PdfPages('DfEP_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Distance From Predicted Equilibrium Price\nLocal Trade Basics", "Distance From Predicted Equilibrium Price Local Trade Basics", "distance_from_equilibrium_price", data, pp, q, -1, 8)
    plt.close('all')
    pp.close()

    pp = PdfPages('FPAMP_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Fifty Period Average Moving Price (Logged) \nLocal Trade Basics", "Fifty Period Average Moving Price (Logged) Local Trade Basics", "fifty_period_RAP", data, pp, q, -1, 8)
    plt.close('all')
    pp.close()

    pp = PdfPages('MRoPC_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Mean Rate of Price Change\nLocal Trade Basics", "Mean Rate of Price Change Local Trade Basics", "mean_rate_of_price_change", data, pp, q, 0, 1)
    plt.close('all')
    pp.close()

    pp = PdfPages('PB_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):    
        color_points("Percent Basic \nLocal Trade Basics", "Percent Basic Local Trade Basics", "percent_basic", data, pp, q, 0, 1)
    plt.close('all')
    pp.close()

    pp = PdfPages('WPC_local_basic_tick_15000.pdf')
    for q in range(999, ticks, interval):        
        color_points("Wealth Per Capita \nLocal Trade Basics", "Wealth Per Capita Local Trade Basics", "basic_only_wealth_per_capita", data, pp, q, 50, 400)                
    plt.close('all')
    pp.close()
                
if __name__ == '__main__':     
    np.save('data',    prepare_lists(files)) 
    np.load('data.npy')