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check by:
MultiDerived.__mro__ MultiDerived.mro()
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MIT
Session 06 - OOP.ipynb
FOU4D/ITI-Python
Encapsulation we denote private attributes using underscore as the prefix i.e single _ or double __
class Cars: def __init__(self): self.__maxprice = 90000 def sell(self): print("Selling Price: {}".format(self.__maxprice)) def setMaxPrice(self, price): self.__maxprice = price toyota = Cars() toyota.sell() # change the price toyota.__maxprice = 1000 toyota.sell() # using sette...
Selling Price: 90000 Selling Price: 90000 Selling Price: 1000
MIT
Session 06 - OOP.ipynb
FOU4D/ITI-Python
polymorphism
class Parrot: def fly(self): print("Parrot can fly") def swim(self): print("Parrot can't swim") class Penguin: def fly(self): print("Penguin can't fly") def swim(self): print("Penguin can swim") # common interface def flying_test(bird): bird.fly() #inst...
Parrot can fly Penguin can't fly
MIT
Session 06 - OOP.ipynb
FOU4D/ITI-Python
0. Imports
# Imports from IPython.display import display, HTML import os import pandas as pd, datetime as dt, numpy as np, matplotlib.pyplot as plt from pandas.tseries.offsets import DateOffset import sys # Display options thisnotebooksys = sys.stdout pd.set_option('display.width', 1000) display(HTML("<style>.container { width:1...
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
1. LOB creation
# b_tape = True means the LOB LOB = mlob.OrderBook(tick_size = 0.5, b_tape = True, # tape transactions b_tape_LOB = True, # tape lob state at each tick verbose = True)
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
2. Data- DTIME : le timestamp de l'ordre- ORDER_ID : l'identifiant de l'ordre- PRICE - QTY- ORDER_SIDE- ORDER_SIDE- ORDER_TYPE : 1 pour Market Order; 2 pour Limit Order; q pour Quote W pour Market On Open;- ACTION_TYPE : I = limit order insertion (passive); C = limit order cacnellations; R = replace order that lo...
df = pd.read_pickle(r'..\data\day20160428.pkl') df
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
3. Agents Creation
auction_config = {'orderbook' : LOB, 'id' : 'FDR', 'b_record' : False, 'historicalOrders' : df[df.DTIME.dt.hour<7]} continuousTrading_config = {'orderbook' : LOB, 'id' : 'FDR', ...
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
4. Replay orders 4.1. Auction phase The auction price shall be determined on the basis of the situation of the Central Order Book at the closing of the call phase and shall be the price which produces the highest executable order volume.
%%time # log f = open('log_auction.txt','w'); sys.stdout = f # Close auction LOB.b_auction = True #Open auction AuctionReplayer.replayOrders() # log sys.stdout = thisnotebooksys
Wall time: 94.1 ms
MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
4.2. Auction is overClosing the auction will result in transactions and a new LOB with unmatched orders will be set.The price is chosen as the one that maximizes volume of transactions.Trades are executed at the auction price, and according to a time priority. The remaining orders at the auction price are the newest o...
%%time # log f = open('log_auctionClose.txt','w'); sys.stdout = f LOB.b_auction = False # log sys.stdout = thisnotebooksys
Wall time: 12.4 ms
MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
4.3. Lob StateLOB state before opening the continuous trading
LOBstate = AuctionReplayer.getLOBState() LOBstate = LOBstate.set_index('Price').sort_index() LOBstate.plot.bar(figsize=(20, 7)) plt.show()
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
4.4. Continuous Trading
%%time # log f = open('log_continuousTrading.txt','w'); sys.stdout = f # Close auction ContReplayer.replayOrders() # log sys.stdout = thisnotebooksys
Wall time: 5min 40s
MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
5. Price Tape
histoPrices = ContReplayer.getPriceTape().astype(float) histoPrices.plot(figsize=(20,7)) # OHLC display(f'open : {histoPrices.iloc[0,0]}') display(f'high : {histoPrices.max()[0]}') display(f'low : {histoPrices.min()[0]}') display(f'close : {histoPrices.iloc[-1, 0]}') plt.show()
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
Get Transaction Tape
TransactionTape = ContReplayer.getTransactionTape() TransactionTape
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
Get LOB Tape The LOB tape is the state of the LOB before each order arrival
LOBtape = AuctionReplayer.getLOBTape() LOBtape
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MIT
demo/Classic/2. Demo - Simulation - Replayer.ipynb
FDR0903/mimicLOB
**Note that this notebook uses private hospita-level data, so can't be run publicly**
%load_ext autoreload %autoreload 2 import numpy as np import scipy as sp import pandas as pd import matplotlib.pyplot as plt from os.path import join as oj import math import pygsheets import pickle as pkl import pandas as pd import seaborn as sns import plotly.express as px from collections import Counter import plotl...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
severity index
df = severity_index.add_severity_index(df, NUM_DAYS_LIST) d = severity_index.df_to_plot(df, NUM_DAYS_LIST) k = 3 s_hosp = f'Predicted Deaths Hospital {k}-day' s_index = f'Severity {k}-day' print('total hospitals', df.shape[0], Counter(df[s_index])) viz_interactive.viz_index_animated(d, [1, 2, 3, 4, 5], ...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
**start with county-level death predictions**
s = f'Predicted Deaths {3}-day' # tot_deaths # s = 'tot_deaths' num_days = 1 nonzero = df[s] > 0 plt.figure(dpi=300, figsize=(7, 3)) plt.plot(df_county[s].values, '.', ms=3) plt.ylabel(s) plt.xlabel('Counties') plt.yscale('log') plt.tight_layout() plt.show()
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
**look at distribution of predicted deaths at hospitals**
num_days = 1 plt.figure(dpi=300, figsize=(7, 3)) offset = 0 for i in [5, 4, 3, 2, 1]: idxs = (df[s_index] == i) plt.plot(np.arange(offset, offset + idxs.sum()), np.clip(df[idxs][s_hosp].values, a_min=1, a_max=None), '.-', label=f'{i}: {severity_index.meanings[i]}') offset += idxs.sum() plt.ys...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
adjustments **different measures of hospital size are pretty consistent**
plt.figure(dpi=500, figsize=(7, 3), facecolor='w') R, C = 1, 3 plt.subplot(R, C, 1) plt.plot(df['Hospital Employees'], df['Total Average Daily Census'], '.', alpha=0.2, markeredgewidth=0) plt.xlabel('Num Hospital Employees') plt.ylabel('Total Average Daily Census') plt.subplot(R, C, 2) plt.plot(df['Hospital Employees'...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
**other measures are harder to parse...**
ks = ['Predicted Deaths Hospital 2-day', "Hospital Employees", 'ICU Beds'] R, C = 1, len(ks) plt.figure(dpi=300, figsize=(C * 3, R * 3)) for c in range(C): plt.subplot(R, C, c + 1) if c == 0: plt.ylabel('Total Occupancy Rate') plt.plot(df[ks[c]], df['Total Occupancy Rate'], '.', alpha=0.5) plt....
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
**different hospital types**
plt.figure(dpi=500, figsize=(7, 3)) R, C = 1, 3 a = 0.5 s = s_hosp plt.subplot(R, C, 1) idxs = df.IsUrbanHospital == 1 plt.hist(df[idxs][s], label='Urban', alpha=a) plt.hist(df[~idxs][s], label='Rural', alpha=a) plt.ylabel('Num Hospitals') plt.xlabel(s) plt.yscale('log') plt.legend() plt.subplot(R, C, 2) idxs = df.IsA...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
**rural areas have lower occupancy rates**
idxs = df.IsUrbanHospital == 1 plt.hist(df['Total Occupancy Rate'][idxs], label='urban', alpha=0.5) plt.hist(df['Total Occupancy Rate'][~idxs], label='rural', alpha=0.5) plt.xlabel('Total Occupancy Rate') plt.ylabel('Count') plt.legend() plt.show() ks = ['ICU Beds', 'Total Beds', 'Hospital Employees', 'Registere...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
look at top counties/hospitals **hospitals per county**
d = df R, C = 1, 2 NUM_COUNTIES = 7 plt.figure(dpi=300, figsize=(7, 3.5)) plt.subplot(R, C, 1) c = 'County Name' county_names = d[c].unique()[:NUM_COUNTIES] num_academic_hospitals = [] # d = df[outcome_keys + hospital_keys] # d = d.sort_values('New Deaths', ascending=False) for county in county_names: num_academ...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
Hospital severity map
counties_json = json.load(open(oj(parentdir, "data", "geojson-counties-fips.json"), "r")) viz_map.plot_hospital_severity_slider( df, df_county=df_county, counties_json=counties_json, dark=False, filename = oj(parentdir, "results", "severity_map.html") )
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
hospital contact info gsheet
ks_orig = ['countyFIPS', 'CountyName', 'Total Deaths Hospital', 'Hospital Name', 'CMS Certification Number', 'StateName', 'System Affiliation'] ks_contact = ['Phone Number', 'Hospital Employees', 'Website', 'Number to Call (NTC)', 'Donation Phone Number', 'Donation Email', 'Notes'] def write_to_gsheets_contact(df, ks_...
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MIT
modeling/hospital_quickstart.ipynb
Alicegif/covid19-severity-prediction
import numpy as np def BSM_characteristic_function(v, x0, T, r, sigma): cf_value = np.exp(((x0 / T + r - 0.5 * sigma ** 2) * 1j * v - 0.5 * sigma ** 2 * v ** 2) * T) return cf_value def BSM_call_characteristic_function(v,alpha, x0, T, r, sigma): res=np.exp(-r*T)/((alpha+1j*v)*(alpha+1j*v+1)...
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MIT
haokai/Speed_Comparison.ipynb
songqsh/Is20f
Raw data for all_snapshots, student at grade 10 and above use DataFrame `raw`
qry = ''' SELECT * from clean.all_snapshots where grade >= 10; ''' cur.execute(qry) rows = cur.fetchall() # Build dataframe from rows raw = pd.DataFrame(rows, columns=[name[0] for name in cur.description]) # Make sure student_id is an int raw['student_lookup'] = raw['student_lookup'].astype('int') raw.head() raw =...
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
Certain districts in certain years seem to not use `withdraw_reason` for grade 12 Zanesville simply lacks data outside of 2015, but other years where there is effectively total missingness on withdraw reason appear to have `graduation_date` listed for most students, and can likely be used as an imputation.
missing_by_district = all_students.join(withdraw_na.groupby(['district','school_year']).agg({'student_lookup':'count'}), rsuffix='_na') missing_by_district[missing_by_district['student_lookup_na'].notnull()]
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
Raw data for withdraw reason for students in 12th grade; also includes any student with a `graduate` withdraw reason since it is possible to graduate early use DataFrame `grad_df`
qry = ''' SELECT student_lookup, grade, school_year, withdraw_reason from clean.all_snapshots where grade = 12 or withdraw_reason = 'graduate' order by student_lookup; ''' cur.execute(qry) rows = cur.fetchall() # Build dataframe from rows grad_df = pd.DataFrame(rows, columns=[name[0] for name in cur.desc...
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
All (student, school_year) entering grade 10
# Gets all students entering grade 10 at school year qry = ''' SELECT distinct student_lookup, grade, school_year from clean.all_snapshots where grade = 10 order by student_lookup; ''' cur.execute(qry) rows = cur.fetchall() # Build dataframe from rows df = pd.DataFrame(rows, columns=[name[0] for name in cur....
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
Links the future "withdraw reason" in grade 12 to the student entering 10th grade Use DataFrame `grd_10`
# Left join means it keeps all 10th grade students, even if they didn't appear in the grad_df grd_10 = pd.merge(df, grad_df, how='left', on='student_lookup') grd_10 grd_10.columns = ['student_lookup', 'grade_10', 'yr_grade_10', 'grade_12', 'yr_grade_12', 'grade_12_withdraw'] grd_10 grd_10.groupby(['yr_grade_10', 'grad...
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
Data obtained by the View (sketch.hs_withdraw_info) WITHOUT further deduplication (grade 10) Use DataFrame `hs_w`
qry = ''' SELECT * from sketch.hs_withdraw_info WHERE grade=10 and entry_year BETWEEN 2007 AND 2013; ''' cur.execute(qry) rows = cur.fetchall() # Build dataframe from rows hs_w = pd.DataFrame(rows, columns=[name[0] for name in cur.description]) # Make sure student_id is an int hs_w ['student_lookup'] = hs_w['studen...
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
Current data retrieval
cur.execute(''' select * from ( SELECT *, ROW_NUMBER() OVER (PARTITION BY student_lookup, grade ORDER BY student_lookup) AS rnum FROM sketch.hs_withdraw_info hwi) t where t.rnum = 1 ...
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MIT
eda/withdraw_reason.ipynb
Karunya-Manoharan/High-school-drop-out-prediction
Repairing Code AutomaticallySo far, we have discussed how to track failures and how to locate defects in code. Let us now discuss how to _repair_ defects – that is, to correct the code such that the failure no longer occurs. We will discuss how to _repair code automatically_ – by systematically searching through possi...
from bookutils import YouTubeVideo YouTubeVideo("UJTf7cW0idI")
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
**Prerequisites*** Re-read the [introduction to debugging](Intro_Debugging.ipynb), notably on how to properly fix code.* We make use of automatic fault localization, as discussed in the [chapter on statistical debugging](StatisticalDebugger.ipynb).* We make extensive use of code transformations, as discussed in [the ch...
import bookutils
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
SynopsisTo [use the code provided in this chapter](Importing.ipynb), write```python>>> from debuggingbook.Repairer import ```and then make use of the following features.This chapter provides tools and techniques for automated repair of program code. The `Repairer()` class takes a `RankingDebugger` debugger as input (s...
from StatisticalDebugger import middle # ignore from bookutils import print_content # ignore import inspect # ignore _, first_lineno = inspect.getsourcelines(middle) middle_source = inspect.getsource(middle) print_content(middle_source, '.py', start_line_number=first_lineno)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
In most cases, `middle()` just runs fine:
middle(4, 5, 6)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
In some other cases, though, it does not work correctly:
middle(2, 1, 3)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Validated Repairs Now, if we only want a repair that fixes this one given failure, this would be very easy. All we have to do is to replace the entire body by a single statement:
def middle_sort_of_fixed(x, y, z): # type: ignore return x
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
You will concur that the failure no longer occurs:
middle_sort_of_fixed(2, 1, 3)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
But this, of course, is not the aim of automatic fixes, nor of fixes in general: We want our fixes not only to make the given failure go away, but we also want the resulting code to be _correct_ (which, of course, is a lot harder). Automatic repair techniques therefore assume the existence of a _test suite_ that can ch...
from StatisticalDebugger import MIDDLE_PASSING_TESTCASES, MIDDLE_FAILING_TESTCASES
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
The `middle_test()` function fails whenever `middle()` returns an incorrect result:
def middle_test(x: int, y: int, z: int) -> None: m = middle(x, y, z) assert m == sorted([x, y, z])[1] from ExpectError import ExpectError with ExpectError(): middle_test(2, 1, 3)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Locating the Defect Our next step is to find potential defect locations – that is, those locations in the code our mutations should focus upon. Since we already do have two test suites, we can make use of [statistical debugging](StatisticalDebugger.ipynb) to identify likely faulty locations. Our `OchiaiDebugger` rank...
from StatisticalDebugger import OchiaiDebugger, RankingDebugger middle_debugger = OchiaiDebugger() for x, y, z in MIDDLE_PASSING_TESTCASES + MIDDLE_FAILING_TESTCASES: with middle_debugger: middle_test(x, y, z)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
We see that the upper half of the `middle()` code is definitely more suspicious:
middle_debugger
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
The most suspicious line is:
# ignore location = middle_debugger.rank()[0] (func_name, lineno) = location lines, first_lineno = inspect.getsourcelines(middle) print(lineno, end="") print_content(lines[lineno - first_lineno], '.py')
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
with a suspiciousness of:
# ignore middle_debugger.suspiciousness(location)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Random Code Mutations Our third step in automatic code repair is to _randomly mutate the code_. Specifically, we want to randomly _delete_, _insert_, and _replace_ statements in the program to be repaired. However, simply synthesizing code _from scratch_ is unlikely to yield anything meaningful – the number of combina...
import string string.ascii_letters len(string.ascii_letters + '_') * \ len(string.ascii_letters + '_' + string.digits) * \ len(string.ascii_letters + '_' + string.digits)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Hence, we do _not_ synthesize code from scratch, but instead _reuse_ elements from the program to be fixed, hypothesizing that "a program that contains an error in one area likely implements the correct behavior elsewhere" \cite{LeGoues2012}. Furthermore, we do not operate on a _textual_ representation of the program, ...
import ast import astor import inspect from bookutils import print_content, show_ast def middle_tree() -> ast.AST: return ast.parse(inspect.getsource(middle)) show_ast(middle_tree())
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
You see that it consists of one function definition (`FunctionDef`) with three `arguments` and two statements – one `If` and one `Return`. Each `If` subtree has three branches – one for the condition (`test`), one for the body to be executed if the condition is true (`body`), and one for the `else` case (`orelse`). Th...
print(ast.dump(middle_tree()))
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
This is the path to the first `return` statement:
ast.dump(middle_tree().body[0].body[0].body[0].body[0]) # type: ignore
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Picking Statements For our mutation operators, we want to use statements from the program itself. Hence, we need a means to find those very statements. The `StatementVisitor` class iterates through an AST, adding all statements to its `statements` list it finds in function definitions. To do so, it subclasses the Pyth...
from ast import NodeVisitor # ignore from typing import Any, Callable, Optional, Type, Tuple from typing import Dict, Union, Set, List, cast class StatementVisitor(NodeVisitor): """Visit all statements within function defs in an AST""" def __init__(self) -> None: self.statements: List[Tuple[ast.AST, st...
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
The function `all_statements()` returns all statements in the given AST `tree`. If an `ast` class `tp` is given, it only returns instances of that class.
def all_statements_and_functions(tree: ast.AST, tp: Optional[Type] = None) -> \ List[Tuple[ast.AST, str]]: """ Return a list of pairs (`statement`, `function`) for all statements in `tree`. If `tp` is given, return only statements of that cl...
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Here are all the `return` statements in `middle()`:
all_statements(middle_tree(), ast.Return) all_statements_and_functions(middle_tree(), ast.If)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
We can randomly pick an element:
import random random_node = random.choice(all_statements(middle_tree())) astor.to_source(random_node)
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Mutating StatementsThe main part in mutation, however, is to actually mutate the code of the program under test. To this end, we introduce a `StatementMutator` class – a subclass of `NodeTransformer`, described in the [official Python `ast` reference](http://docs.python.org/3/library/ast). The constructor provides var...
from ast import NodeTransformer import copy class StatementMutator(NodeTransformer): """Mutate statements in an AST for automated repair.""" def __init__(self, suspiciousness_func: Optional[Callable[[Tuple[Callable, int]], float]] = None, source: Optiona...
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Choosing Suspicious Statements to MutateWe start with deciding which AST nodes to mutate. The method `node_suspiciousness()` returns the suspiciousness for a given node, by invoking the suspiciousness function `suspiciousness_func` given during initialization.
import warnings class StatementMutator(StatementMutator): def node_suspiciousness(self, stmt: ast.AST, func_name: str) -> float: if not hasattr(stmt, 'lineno'): warnings.warn(f"{self.format_node(stmt)}: Expected line number") return 0.0 suspiciousness = self.suspiciousness_f...
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
The method `node_to_be_mutated()` picks a node (statement) to be mutated. It determines the suspiciousness of all statements, and invokes `random.choices()`, using the suspiciousness as weight. Unsuspicious statements (with zero weight) will not be chosen.
class StatementMutator(StatementMutator): def node_to_be_mutated(self, tree: ast.AST) -> ast.AST: statements = all_statements_and_functions(tree) assert len(statements) > 0, "No statements" weights = [self.node_suspiciousness(stmt, func_name) for stmt, func_name in state...
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Choosing a Mutation Method The method `visit()` is invoked on all nodes. For nodes marked with a `mutate_me` attribute, it randomly chooses a mutation method (`choose_op()`) and then invokes it on the node.According to the rules of `NodeTransformer`, the mutation method can return* a new node or a list of nodes, repla...
import re RE_SPACE = re.compile(r'[ \t\n]+') class StatementMutator(StatementMutator): def choose_op(self) -> Callable: return random.choice([self.insert, self.swap, self.delete]) def visit(self, node: ast.AST) -> ast.AST: super().visit(node) # Visits (and transforms?) children if not...
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MIT
notebooks/Repairer.ipynb
bjrnmath/debuggingbook
Swapping StatementsOur first mutator is `swap()`, which replaces the current node NODE by a random node found in `source` (using a newly defined `choose_statement()`).As a rule of thumb, we try to avoid inserting entire subtrees with all attached statements; and try to respect only the first line of a node. If the new...
class StatementMutator(StatementMutator): def choose_statement(self) -> ast.AST: return copy.deepcopy(random.choice(self.source)) class StatementMutator(StatementMutator): def swap(self, node: ast.AST) -> ast.AST: """Replace `node` with a random node from `source`""" new_node = self.choo...
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Inserting StatementsOur next mutator is `insert()`, which randomly chooses some node from `source` and inserts it after the current node NODE. (If NODE is a `return` statement, then we insert the new node _before_ NODE.)If the statement to be inserted has the form```pythonif P: BODY```we only insert the "header" of...
class StatementMutator(StatementMutator): def insert(self, node: ast.AST) -> Union[ast.AST, List[ast.AST]]: """Insert a random node from `source` after `node`""" new_node = self.choose_statement() if isinstance(new_node, ast.stmt) and hasattr(new_node, 'body'): # Inserting `if P...
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Deleting StatementsOur last mutator is `delete()`, which deletes the current node NODE. The standard case is to replace NODE by a `pass` statement.If the statement to be deleted has the form```pythonif P: BODY```we only delete the "header" of the `if`, resulting in```pythonBODY```Again, this applies to all construc...
class StatementMutator(StatementMutator): def delete(self, node: ast.AST) -> None: """Delete `node`.""" branches = [attr for attr in ['body', 'orelse', 'finalbody'] if hasattr(node, attr) and getattr(node, attr)] if branches: # Replace `if P: S` by `S` ...
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Indeed, Python's `compile()` will fail if any of the bodies is an empty list. Also, it leaves us a statement that can be evolved further. HelpersFor logging purposes, we introduce a helper function `format_node()` that returns a short string representation of the node.
class StatementMutator(StatementMutator): NODE_MAX_LENGTH = 20 def format_node(self, node: ast.AST) -> str: """Return a string representation for `node`.""" if node is None: return "None" if isinstance(node, list): return "; ".join(self.format_node(elem) for ele...
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All TogetherLet us now create the main entry point, which is `mutate()`. It picks the node to be mutated and marks it with a `mutate_me` attribute. By calling `visit()`, it then sets off the `NodeTransformer` transformation.
class StatementMutator(StatementMutator): def mutate(self, tree: ast.AST) -> ast.AST: """Mutate the given AST `tree` in place. Return mutated tree.""" assert isinstance(tree, ast.AST) tree = copy.deepcopy(tree) if not self.source: self.source = all_statements(tree) ...
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Here are a number of transformations applied by `StatementMutator`:
mutator = StatementMutator(log=True) for i in range(10): new_tree = mutator.mutate(middle_tree())
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This is the effect of the last mutator applied on `middle`:
print_content(astor.to_source(new_tree), '.py')
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FitnessNow that we can apply random mutations to code, let us find out how good these mutations are. Given our test suites for `middle`, we can check for a given code candidate how many of the previously passing test cases it passes, and how many of the failing test cases it passes. The more tests pass, the higher the...
WEIGHT_PASSING = 0.99 WEIGHT_FAILING = 0.01 def middle_fitness(tree: ast.AST) -> float: """Compute fitness of a `middle()` candidate given in `tree`""" original_middle = middle try: code = compile(tree, '<fitness>', 'exec') except ValueError: return 0 # Compilation error exec(code...
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Our faulty `middle()` program has a fitness of `WEIGHT_PASSING` (99%), because it passes all the passing tests (but none of the failing ones).
middle_fitness(middle_tree())
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Our "sort of fixed" version of `middle()` gets a much lower fitness:
middle_fitness(ast.parse("def middle(x, y, z): return x"))
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In the [chapter on statistical debugging](StatisticalDebugger), we also defined a fixed version of `middle()`. This gets a fitness of 1.0, passing all tests. (We won't use this fixed version for automated repairs.)
from StatisticalDebugger import middle_fixed middle_fixed_source = \ inspect.getsource(middle_fixed).replace('middle_fixed', 'middle').strip() middle_fitness(ast.parse(middle_fixed_source))
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PopulationWe now set up a _population_ of fix candidates to evolve over time. A higher population size will yield more candidates to check, but also need more time to test; a lower population size will yield fewer candidates, but allow for more evolution steps. We choose a population size of 40 (from \cite{LeGoues20...
POPULATION_SIZE = 40 middle_mutator = StatementMutator() MIDDLE_POPULATION = [middle_tree()] + \ [middle_mutator.mutate(middle_tree()) for i in range(POPULATION_SIZE - 1)]
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We sort the fix candidates according to their fitness. This actually runs all tests on all candidates.
MIDDLE_POPULATION.sort(key=middle_fitness, reverse=True)
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The candidate with the highest fitness is still our original (faulty) `middle()` code:
print(astor.to_source(MIDDLE_POPULATION[0]), middle_fitness(MIDDLE_POPULATION[0]))
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At the other end of the spectrum, the candidate with the lowest fitness has some vital functionality removed:
print(astor.to_source(MIDDLE_POPULATION[-1]), middle_fitness(MIDDLE_POPULATION[-1]))
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EvolutionTo evolve our population of candidates, we fill up the population with mutations created from the population, using a `StatementMutator` as described above to create these mutations. Then we reduce the population to its original size, keeping the fittest candidates.
def evolve_middle() -> None: global MIDDLE_POPULATION source = all_statements(middle_tree()) mutator = StatementMutator(source=source) n = len(MIDDLE_POPULATION) offspring: List[ast.AST] = [] while len(offspring) < n: parent = random.choice(MIDDLE_POPULATION) offspring.append(...
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This is what happens when evolving our population for the first time; the original source is still our best candidate.
evolve_middle() tree = MIDDLE_POPULATION[0] print(astor.to_source(tree), middle_fitness(tree))
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However, nothing keeps us from evolving for a few generations more...
for i in range(50): evolve_middle() best_middle_tree = MIDDLE_POPULATION[0] fitness = middle_fitness(best_middle_tree) print(f"\rIteration {i:2}: fitness = {fitness} ", end="") if fitness >= 1.0: break
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Success! We find a candidate that actually passes all tests, including the failing ones. Here is the candidate:
print_content(astor.to_source(best_middle_tree), '.py', start_line_number=1)
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... and yes, it passes all tests:
original_middle = middle code = compile(best_middle_tree, '<string>', 'exec') exec(code, globals()) for x, y, z in MIDDLE_PASSING_TESTCASES + MIDDLE_FAILING_TESTCASES: middle_test(x, y, z) middle = original_middle
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As the code is already validated by hundreds of test cases, it is very valuable for the programmer. Even if the programmer decides not to use the code as is, the location gives very strong hints on which code to examine and where to apply a fix. However, a closer look at our fix candidate shows that there is some amoun...
quiz("Some of the lines in our fix candidate are redundant. Which are these?", [ "Line 3: `if x < y`", "Line 4: `if x > z`", "Line 5: `return x`", "Line 13: `return z`" ], '[eval(chr(100 - x)) for x in [49, 50]]')
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Simplifying As demonstrated in the chapter on [reducing failure-inducing inputs](DeltaDebugger.ipynb), we can use delta debugging on code to get rid of these superfluous statements. The trick for simplification is to have the test function (`test_middle_lines()`) declare a fitness of 1.0 as a "failure". Delta debuggin...
from DeltaDebugger import DeltaDebugger middle_lines = astor.to_source(best_middle_tree).strip().split('\n') def test_middle_lines(lines: List[str]) -> None: source = "\n".join(lines) tree = ast.parse(source) assert middle_fitness(tree) < 1.0 # "Fail" only while fitness is 1.0 with DeltaDebugger() as dd: ...
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Success! Delta Debugging has eliminated the superfluous statements. We can present the difference to the original as a patch:
original_source = astor.to_source(ast.parse(middle_source)) # normalize from ChangeDebugger import diff, print_patch # minor dependency for patch in diff(original_source, repaired_source): print_patch(patch)
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We can present this patch to the programmer, who will then immediately know what to fix in the `middle()` code. CrossoverSo far, we have only applied one kind of genetic operators – mutation. There is a second one, though, also inspired by natural selection. The *crossover* operation mutates two strands of genes, as i...
def p1(): # type: ignore a = 1 b = 2 c = 3 def p2(): # type: ignore x = 1 y = 2 z = 3
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Then a crossover operation would produce one child with a body```pythona = 1y = 2z = 3```and another child with a body```pythonx = 1b = 2c = 3``` We can easily implement this in a `CrossoverOperator` class in a method `cross_bodies()`.
class CrossoverOperator: """A class for performing statement crossover of Python programs""" def __init__(self, log: bool = False): """Constructor. If `log` is set, turn on logging.""" self.log = log def cross_bodies(self, body_1: List[ast.AST], body_2: List[ast.AST]) -> \ Tuple[Li...
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Here's the `CrossoverOperatorMutator` applied on `p1` and `p2`:
tree_p1: ast.Module = ast.parse(inspect.getsource(p1)) tree_p2: ast.Module = ast.parse(inspect.getsource(p2)) body_p1 = tree_p1.body[0].body # type: ignore body_p2 = tree_p2.body[0].body # type: ignore body_p1 crosser = CrossoverOperator() tree_p1.body[0].body, tree_p2.body[0].body = crosser.cross_bodies(body_p1, bod...
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Applying Crossover on ProgramsApplying the crossover operation on arbitrary programs is a bit more complex, though. We first have to _find_ lists of statements that we a actually can cross over. The `can_cross()` method returns True if we have a list of statements that we can cross. Python modules and classes are excl...
class CrossoverOperator(CrossoverOperator): # In modules and class defs, the ordering of elements does not matter (much) SKIP_LIST = {ast.Module, ast.ClassDef} def can_cross(self, tree: ast.AST, body_attr: str = 'body') -> bool: if any(isinstance(tree, cls) for cls in self.SKIP_LIST): r...
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Here comes our method `crossover_attr()` which searches for crossover possibilities. It takes to ASTs `t1` and `t2` and an attribute (typically `'body'`) and retrieves the attribute lists $l_1$ (from `t1.`) and $l_2$ (from `t2.`).If $l_1$ and $l_2$ can be crossed, it crosses them, and is done. Otherwise* If there is a ...
class CrossoverOperator(CrossoverOperator): def crossover_attr(self, t1: ast.AST, t2: ast.AST, body_attr: str) -> bool: """ Crossover the bodies `body_attr` of two trees `t1` and `t2`. Return True if successful. """ assert isinstance(t1, ast.AST) assert isinstance(t2,...
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We have a special case for `if` nodes, where we can cross their body and `else` branches.
class CrossoverOperator(CrossoverOperator): def crossover_branches(self, t1: ast.AST, t2: ast.AST) -> bool: """Special case: `t1` = `if P: S1 else: S2` x `t2` = `if P': S1' else: S2'` becomes `t1` = `if P: S2' else: S1'` and `t2` = `if P': S2 else: S1` Returns True if success...
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The method `crossover()` is the main entry point. It checks for the special `if` case as described above; if not, it searches for possible crossover points. It raises `CrossoverError` if not successful.
class CrossoverOperator(CrossoverOperator): def crossover(self, t1: ast.AST, t2: ast.AST) -> Tuple[ast.AST, ast.AST]: """Do a crossover of ASTs `t1` and `t2`. Raises `CrossoverError` if no crossover is found.""" assert isinstance(t1, ast.AST) assert isinstance(t2, ast.AST) f...
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End of Excursion Crossover in Action Let us put our `CrossoverOperator` in action. Here is a test case for crossover, involving more deeply nested structures:
def p1(): # type: ignore if True: print(1) print(2) print(3) def p2(): # type: ignore if True: print(a) print(b) else: print(c) print(d)
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We invoke the `crossover()` method with two ASTs from `p1` and `p2`:
crossover = CrossoverOperator() tree_p1 = ast.parse(inspect.getsource(p1)) tree_p2 = ast.parse(inspect.getsource(p2)) crossover.crossover(tree_p1, tree_p2);
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Here is the crossed offspring, mixing statement lists of `p1` and `p2`:
print_content(astor.to_source(tree_p1), '.py') print_content(astor.to_source(tree_p2), '.py')
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Here is our special case for `if` nodes in action, crossing our `middle()` tree with `p2`.
middle_t1, middle_t2 = crossover.crossover(middle_tree(), ast.parse(inspect.getsource(p2)))
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We see how the resulting offspring encompasses elements of both sources:
print_content(astor.to_source(middle_t1), '.py') print_content(astor.to_source(middle_t2), '.py')
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A Repairer ClassSo far, we have applied all our techniques on the `middle()` program only. Let us now create a `Repairer` class that applies automatic program repair on arbitrary Python programs. The idea is that you can apply it on some statistical debugger, for which you have gathered passing and failing test cases,...
from StackInspector import StackInspector # minor dependency class Repairer(StackInspector): """A class for automatic repair of Python programs""" def __init__(self, debugger: RankingDebugger, *, targets: Optional[List[Any]] = None, sources: Optional[List[Any]] = None, ...
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When we access or execute functions, we ault_functionso \todo{What? -- BM} so in the caller's environment, not ours. The `caller_globals()` method from `StackInspector` acts as replacement for `globals()`. Helper FunctionsThe constructor uses a number of helper functions to create its environment.
class Repairer(Repairer): def getsource(self, item: Union[str, Any]) -> str: """Get the source for `item`. Can also be a string.""" if isinstance(item, str): item = self.globals[item] return inspect.getsource(item) class Repairer(Repairer): def default_functions(self) -> Lis...
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Running TestsNow that we have set the environment for `Repairer`, we can implement one step of automatic repair after the other. The method `run_test_set()` runs the given `test_set` (`DifferenceDebugger.PASS` or `DifferenceDebugger.FAIL`), returning the number of passed tests. If `validate` is set, it checks whether ...
class Repairer(Repairer): def run_test_set(self, test_set: str, validate: bool = False) -> int: """ Run given `test_set` (`DifferenceDebugger.PASS` or `DifferenceDebugger.FAIL`). If `validate` is set, check expectations. Return number of passed tests. """ pass...
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Here is how we use `run_tests_set()`:
repairer = Repairer(middle_debugger) assert repairer.run_test_set(middle_debugger.PASS) == \ len(MIDDLE_PASSING_TESTCASES) assert repairer.run_test_set(middle_debugger.FAIL) == 0
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The method `run_tests()` runs passing and failing tests, weighing the passed testcases to obtain the overall fitness.
class Repairer(Repairer): def weight(self, test_set: str) -> float: """ Return the weight of `test_set` (`DifferenceDebugger.PASS` or `DifferenceDebugger.FAIL`). """ return { self.debugger.PASS: WEIGHT_PASSING, self.debugger.FAIL: WEIGHT_FAILING ...
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The method `validate()` ensures the observed tests can be adequately reproduced.
class Repairer(Repairer): def validate(self) -> None: fitness = self.run_tests(validate=True) assert fitness == self.weight(self.debugger.PASS) repairer = Repairer(middle_debugger) repairer.validate()
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(Re)defining FunctionsOur `run_tests()` methods above do not yet redefine the function to be repaired. This is done by the `fitness()` function, which compiles and defines the given repair candidate `tree` before testing it. It caches and returns the fitness.
class Repairer(Repairer): def fitness(self, tree: ast.AST) -> float: """Test `tree`, returning its fitness""" key = cast(str, ast.dump(tree)) if key in self.fitness_cache: return self.fitness_cache[key] # Save defs original_defs: Dict[str, Any] = {} for n...
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