* Remove unnecessary goal test in search.py (aimacode#953)

Remove unnecessary initial goal test in best_first_graph_search. The loop will catch that case immediately.

* Minor Changes in Text (aimacode#955)

* Minor text change (aimacode#957)

To make it more accurate.

* Minor change in text (aimacode#956)

To make it more descriptive and accurate.

* Added relu Activation (aimacode#960)

* added relu activation

* added default parameters

* Changes in texts (aimacode#959)

Added a few new sentences, modified the sentence structure at a few places, and corrected some grammatical errors.

* Change PriorityQueue expansion (aimacode#962)

`self.heap.append` simply appends to the end of the `self.heap` 
Since `self.heap` is just a python list. 
`self.append` calls the append method of the class instance, effectively putting the item in its proper place.

* added GSoC 2018 contributors

A thank you to contributors from the GSoC 2018 program!

* Revamped the notebook (aimacode#963)

* Revamped the notebook

* A few changes reversed

Changed a few things from my original PR after a review from ad71.

* Text Changes + Colored Table (aimacode#964)

Made a colored table to display dog movement instead. Corrected grammatical errors, improved the sentence structure and corrected any typos found.

* Fixed typos (aimacode#970)

Typos and minor other text errors removed

* Fixed Typos (aimacode#971)

Corrected typos + minor other text changes

* Update intro.ipynb (aimacode#969)

* Added activation functions (aimacode#968)

* Updated label_queen_conflicts function (aimacode#967)

Shortened it, finding conflicts separately and storing them in different variables has no use later in the notebook; so i believe this looks better.

* Probability: Notebook + gibbs_ask test (aimacode#653)

* probability notebook

* Update test_probability.py

* Update README.md

* add gsoc write-ups (aimacode#654)

* Fix typo in docstring (aimacode#660)

* Fixed Key Error bug in CustomMDP  (aimacode#658)

* fixed Key Error bug in CustomMDP and reordered the return values of T function to be consistent with GridMDP

* removing idea files from git

* fix typos & grammar (aimacode#656)

* Update README.md (aimacode#669)

* '>' to '>=' (aimacode#668)

* fix typo for issue#664 (aimacode#665)

* Adding Tkinter GUI  (aimacode#661)

* tic-tac-toe gui added

* Added GUI for Searching

* Added Legend and Minor Fix

* Minor Fix and Options added

* Added Breadth-First Tree Search

* Added Depth-First Tree Search

* Minor Fix

* Added Depth-First Graph Search

* Fixed typo (aimacode#675)

Closes aimacode#673

* Adding Tkinter GUI (2) and Visualization in notebook (aimacode#670)

* tic-tac-toe gui added

* Added GUI for Searching

* Added Legend and Minor Fix

* Minor Fix and Options added

* Added Breadth-First Tree Search

* Added Depth-First Tree Search

* Minor Fix

* Added Depth-First Graph Search

* Minor Fix

* Breadth-First Search and Minor Fix

* Added Depth-First Graph Search in notebook

* Added Depth-First Tree Search in notebook

* Cell Placement

* Adding Tkinter GUI (aimacode#677)

* tic-tac-toe gui added

* Added GUI for Searching

* Added Legend and Minor Fix

* Minor Fix and Options added

* Added Breadth-First Tree Search

* Added Depth-First Tree Search

* Minor Fix

* Added Depth-First Graph Search

* Minor Fix

* Breadth-First Search and Minor Fix

* Added Depth-First Graph Search in notebook

* Added Depth-First Tree Search in notebook

* Cell Placement

* Added Uniform Cost Search in GUI

* update genetic algorithm (aimacode#676)

* Fix small typo in documentation (aimacode#681)

* Update search.py (aimacode#680)

* Added A*-Search in GUI (aimacode#679)

* add Astar heuristics (aimacode#685)

* Add simulated annealing visualisation through TSP (aimacode#694)

Partially solves aimacode#687

* Added Decision Tree Learner example to learning.ipynb. (aimacode#686)

* added example for Decision Tree Learner

* fixed docstring in learning.py and description in learning.ipynb

* Adding Tkinter GUI (aimacode#693)

* Added Vacuum Agent

* Minor Fix

* Improved Font

* Added XYVacuumEnv

* Minor Fix

* Review changes

*  Update PeakFindingProblem code to allow diagonal motion (aimacode#684)

* Update PeakFindingProblem code to allow diagonal motion

* Fix unit test issues

* update PeakFindingProblem to take actions as input param

* Refactor code in search.py

* Visualisation of TSP. (aimacode#699)

Add features like selecting cities to be part of tsp, controlling temperature and speed of
animation.

* Add reset button for XYEnv (aimacode#698)

* Solve Issue of Loading search.ipynb (aimacode#689)

* rebase with master

* solve error

* solve error

* solve error

* Update search.ipynb

* Fixed issue aimacode#700 (aimacode#701)

* Explanation of genetic algorithm functions with an example. Fixed aimacode#696 (aimacode#702)

* Added explanation of Genetic Algorithm functions using an example

* Added GUI version of genetic algorithm example (phrase generation problem)

* added Best First search in search.ipynb (aimacode#708)

* added Best First search

* fixed minor conflicts

* minor changes

* Adding algorithm selection menu for TSP (aimacode#706)

* Added dropdown option to solve using genetic algorithm

* Added option to solve using Hill Climbing

* Added messagebox to confirm exit

* added function to implement uniform crossover (aimacode#704)

* Updated move dictionary (aimacode#715)

* improved search.ipynb (aimacode#716)

* added submodule

* removed duplicates

* minor changes

* Update README.md

* removed an unwanted commit

* Added GridMDP editor to create and solve grid-world problems (Closes aimacode#713) (aimacode#719)

* Added GridMDP editor to create and solve grid-world problems

* Added reference to grid_mdp.py in mdp.ipynb

* Replacing %psource with psource function

* Print matrix to console as well

* modify AC3 algorithm (aimacode#717)

* added submodule

* fixed ac3 in csp.py

* added a test to verify the modified ac3 algorithm in csp.py

* Update .gitmodules

* Add vacuum_world.ipynb (aimacode#721)

* Added vacuum_world.ipynb

* Add psource for environment

* Add explanation for Simple Problem Solving Agent (aimacode#724)

* Add SimpleProblemSolvingAgent

* Fix typo in search.py

* Added more tests for mdp.py (aimacode#722)

* Update vacuum_world.ipynb (aimacode#725)

* Adaboost example (aimacode#739)

* added overview for AdaBoost

* added implementation for AdaBoost

* added example for AdaBoost

* added tests for AdaBoost

* rephrased sentences

* final changes to AdaBoost

* changed adaboost tests to use grade_learner

* grammar check

* Enhanced mdp notebook (aimacode#743)

* Added Policy Iteration section

* Removed ambiguous test

* Capitalized header

* Added images

* Added section for sequential decision problems

* Update search.ipynb (aimacode#726)

* Fix EightPuzzle class implementation in search.py (aimacode#710) (aimacode#733)

* Fix EightPuzzle class implementation

* Fix EightPuzzle class implementation (aimacode#710)

* Address style issues (aimacode#710)

* Modified table for TableDrivenVacuumAgent (aimacode#738)

* Enhanced explanation of value iteration (aimacode#736)

* Enhanced explanation of value iteration

* Fixed minor typo

* Minor enhancement to grid_mdp editor (aimacode#734)

* Fixed reset function to reset placeholder variables as well

* Added functionality to display best policy

* Fix aimacode#731: Add table and tests for TableDrivenVacuumAgent (aimacode#732)

* Add test for TableDrivenVacuumAgent

* Debug Travis

* Minor fix

* Fixed table for TableDrivenAgent

* Update README

* Update text.py (aimacode#740)

* Fix aimacode#741: Add learning agent to vacuum_world.ipynb (aimacode#742)

* Modified table for TableDrivenVacuumAgent

* Add learing agent

* Add image for learning agent

* Learning: Neural Net Test + Minor Styling Fix (aimacode#746)

* Update learning.py

* Update test_learning.py

* Fix various typos. (aimacode#750)

* Added tests for information_content (aimacode#753)

* Added tests for information_content

Added some tests for information_content function from learning.py

* Added test for information_content

* Added Node in search.ipynb (aimacode#761)

* fixing build

* Update README.md (aimacode#767)

* Minor update in search.ipynb (aimacode#763)

* Update nlp_apps.ipynb (aimacode#764)

* Updated README.md (aimacode#771)

* Update README.md

* Update SUBMODULE.md

* added Done tag for adaboost (aimacode#774)

* csp.ipynb: removed some typos (aimacode#769)

* Update README.md

* Add test for table_driven_agent_program and Random_agent_program (aimacode#770)

* Add test for table driven agent

* Some style fixes

* Added done to tabledrivenagent test in readme

* Added randomAgentProgram test to test_agents.py

* Added Import randomAgentProgram

* Style fixes

* Added the done tag tp tabledrivenagent test

* Update README.md (aimacode#773)

* Fixed typos and added inline LaTeX to mdp.ipynb (aimacode#776)

* Fixed typos and added inline LaTeX

* Fixed more backslashes

* Added mdp_apps notebook (aimacode#778)

* Added mdp_apps notebook

* Added images

* LaTeX formatting errors fixed

* Minor fix in typo (aimacode#779)

* Minor typos (aimacode#780)

* Added TableDrivenAgentProgram tests (aimacode#777)

* Add tests for TableDrivenAgentProgram

* Add tests for TableDrivenAgentProgram

* Check environment status at every step

* Check environment status at every step of TableDrivenAgentProgram

* Enhanced mdp_apps notebook (aimacode#782)

* Added pathfinding example

* Added images

* Backgammon implementation (aimacode#783)

* Create model classes for backgammon

* Add game functions to model

* Implement expectiminimax function

* Correct logic in some functions

* Correct expectiminimax logic

* Refactor code and add docstrings

* Remove print statements

* Added section on Hill Climbing (aimacode#787)

* Added section on Hill Climbing

* Added images

* Updated README.md

* Added test for simpleProblemSolvingAgentProgram (aimacode#784)

* Added test for simpleProblemSolvingAgent

* Some Style fixes

* Fixed update_state in test_search.py

* Fix MDP class and add POMDP subclass and notebook (aimacode#781)

* Fixed typos and added inline LaTeX

* Fixed backslash for inline LaTeX

* Fixed more backslashes

* generalised MDP class and created POMDP notebook

* Fixed consistency issues with base MDP class

* Small fix on CustomMDP

* Set default args to pass tests

* Added TableDrivenAgentProgram tests (aimacode#777)

* Add tests for TableDrivenAgentProgram

* Add tests for TableDrivenAgentProgram

* Check environment status at every step

* Check environment status at every step of TableDrivenAgentProgram

* Fixing tests

* fixed test_rl

* removed redundant code, fixed a comment

* Ignoring .DS_Store for macOS (aimacode#788)

* Removed a repeating cell (aimacode#789)

* Updated index (aimacode#790)

* Updated README.md (aimacode#794)

* Replace Point class with dict (aimacode#798)

* Add to rl module (aimacode#799)

* Ignoring .DS_Store for macOS

* Added Direct Utility Estimation code and fixed notebook

* Added implementation to README.md

* Added tt-entails explanation (aimacode#793)

* added tt-entails explanation

* Updated README.md

* Added simple problem solving agent in search.ipynb (aimacode#795)

* Update README.md (aimacode#796)

* Resolved merge conflicts in mdp.ipynb (aimacode#801)

* Resolved merge conflicts

* Rerun

* Metadata restored

* Added to-cnf (aimacode#802)

* Update CONTRIBUTING.md (aimacode#806)

* Remove commented codes in agents.ipynb (aimacode#805)

* Minor formatting issues (aimacode#832)

* Add injection

A new function, `injection` for dependency injection of globals (for classes and functions that weren't designed for dependency injection).

* styling and several bug fixes in learning.py (aimacode#831)

* styling changes and bug fixes in learning.py

* Fix aimacode#833 and other pep corrections in mdp.py

* minor change mdp.py

* renamed train_and_test() to train_test_split() aimacode#55 aimacode#830

* typo fix

* Added DPLL and WalkSAT sections (aimacode#823)

* Added dpll section

* Updated README.md

* Added WalkSAT section

* Updated README.md

* Added test for SimpleReflexAgentProgram (aimacode#808)

* Added test for simpleReflexAgent

* Fixed a bug

* Fixed another bug

* Move viz code + changes to search (aimacode#812)

* Updating submodule

* Moved viz code to notebook.py + changes

* Changed use of 'next'

* Added networkx to .travis.yml

* Added others to .travis.yml

* Remove time from .travis.yml

* Added linebreaks and fixed case for no algo

* Fixed spaces for args

* Renamed *search as *search_for_vis

* Added air_cargo to planning.ipynb (aimacode#835)

* Added air_cargo to planning.ipynb

* Some style issues

* fixed all instances of issue aimacode#833 (aimacode#843)

* test commit

* agents.ipynb

* agents.ipynb

* Fixed all the instances of issue aimacode#833

* minor fix and cleared change in agents.ipynb

* Added min-conflicts section (aimacode#841)

* Added section on min-conflicts

* Refactor one-liner for loop

* Added tests for min_conflicts and NQueensCSP

* Rewrote parts of search.ipynb (aimacode#809)

* Rewrote parts of search.ipynb

* Fixed typo and cleared cell output

* Added pl-fc-entails section (aimacode#818)

* Added pl-fc-entails section

* Updated README.md

* Updated filename

* Added tests for pl-fc-entails

* Review fixes

* Implemented HybridWumpusAgent (aimacode#842)

* Added WumpusKB for use in HybridWumpusAgent

* Implemented HybridWumpusAgent 

added WumpusPosition helping class.

* Forward-Backward examples added to the probability.ipynb. Fixes issue aimacode#813 (aimacode#827)

* Forward-Backward examples added to the ipynb. Fixes issue aimacode#813

* Forward-Backward examples added to the probability.ipynb. Fixes issue aimacode#813

* Convert Latex syntax to Markdown except from the equations with subscript characters

* Add test for TableDrivenAgentProgram. (aimacode#749)

Fixes aimacode#748.

* Refactored EightPuzzle class (aimacode#807)

* Refactor EightPuzzle class

* return instead of print

* Added tests for EightPuzzle

* Review fixes

* Review fixes

* Fixed tests

* Update inverted commas in docstrings

* Changed plotting function for NQueensCSP (aimacode#847)

* Updated README.md

* Added function to plot NQueensProblem

* Added queen image

* Changed plotting function for NQueensCSP

* Replaced f'{}' with .format() notation

* Added Pillow to travis.yml

* Refactored N-Queens problem (aimacode#848)

* NQueensProblem returns tuples as states

* Reran search.ipynb

* List to tuple

* Changed default value and add heuristic function

* Added astar_search for NQueensProblem

* Added tests for NQueensProblem

* Fix various issues in backgammon and expectiminimax (aimacode#849)

* Fix expectiminimax and utility issues

* Correct result function

* Fix issue with dice roll in different states

* Refactor code

* Added missing tests (aimacode#854)

* Added Random Forest Learner in learning.ipynb (aimacode#855)

* fix aimacode#844 Added Random Forest Learner

* Update learning.ipynb

* Update learning.ipynb

* Add files via upload

* Updated image source

* Added Random Forest in contents section

* Added sections on learning.ipynb (aimacode#851)

* Updated README.md (aimacode#864)

* Added missing execution_count (aimacode#867)

* updated vacuum_world.ipynb (aimacode#869)

* fixed typos

* fixed several typos

* Corrected test_compare_agents() function

TrivialVacuumEnvironment was missing a pair of parenthesis while creating the "environment" object of the TrivialVacuumEnvironment class
ModelBasedVacuumAgent and ReflexVacuumAgent were also missing parenthesis while creating the "agents" object.

* Reverted changes made to test_compare_agents()

* fixed typo

* Assemble all backgammon code in a single class (aimacode#868)

* Remove BackgammonBoard class

* Refactor code

* Added Simulated Annealing to search notebook (aimacode#866)

* A few helper functions

* Added Simulated Annealing

* Updated README.md

* Refactored WumpusKB and HybridWumpusAgent to use Expr obejcts (aimacode#862)

* Added ask_with_dpll to WumpusKB

* Refactored WumpusKB

* Refactored HybridWumpusAgent

* No need for ask_with_dpll, fix typos

* override ask_if_true in WumpusKB

* remove extra line

* Added gui version for eight_puzzle (aimacode#861)

* Added SATPlan to logic.ipynb (aimacode#857)

* Added SATPlan to logic.ipynb

* Updated README.md

* Removed all Rule mechanism (aimacode#859)

* Correction in the formula for mean square error (aimacode#850)

* added min_consistent_det to knowledge.ipynb (aimacode#860)

* added min_consistent_det to knowledge.ipynb

* some minor changes

* Added function and test cases for cross-entropy loss (aimacode#853)

* Correction in the formula for mean square error

* Added cross-entropy loss

* Test case for cross-entropy loss

* Decimal point mistake

* Added spaces around = and ==

* Added test case for CYK_parse (aimacode#816)

* added test case for CYK_parse

* added testcase for CYK_parse

* corrected spacing

* fixed issues like alignment, missing comma etc.

* test case for double tennis problem

* Update planning.py

removed commented print statements.

* refactored FIFOQueue, Stack, and PriorityQueue (aimacode#878)

* Added Depth Limited Search in search.ipynb (aimacode#876)

* Added Depth Limited Search in search.ipynb

* Made changes in depth limited search

* Implemented plan_route and plan_shot  (aimacode#872)

* define plan_route, plan_shot and refactor code

* minor changes

* Added PlanRoute Problem class

* update plan_route

return list of actions ( node.solution() ) instead of node itself in plan_route

* add federalist papers classification (aimacode#887)

* Update nlp_apps.ipynb (aimacode#888)

* Added ensemble learner (aimacode#884)

* Added ensemble learner in learning.ipynb

* Added ensemble_learner.jpg

* Update learning.ipynb

* Update learning.ipynb

* Added Iterative deepening search in search.ipynb (aimacode#879)

* Added linear learner (aimacode#889)

* Added linear learner in learning.ipynb

* Update learning.ipynb

* Update learning.ipynb

* Update learning.ipynb

* Renaming image (aimacode#900)

* deleting

* reuploading

* Fixed errors occurred in search.ipynb due to refactoring  (aimacode#902)

* refactored changes

* added DLS and IDS to readme

* added have_cake_and_eat_cake_too (aimacode#906)

* added have_cake_and_eat_cake_too

* renamed effect_neg to effect_rem

* added have_cake_and_eat_cake_too to readme

* added details to Problems in planning.ipynb

Added more information for the problems Air Cargo, Spare Tire, Three Block Tower, Have Cake and Eat Cake Too.

* removed a test from planning.py

A test for three block tower problem is written here. I have removed it.

* Style fixes

* minor style fix

* fixed a typo

* minor fixes

some sentence issues

* minor changes

* minor fixes

* Add play_game function and fix backgammon game play issues (aimacode#904)

* Resolve recursion issue in Backgammon class

* Handle empty action list in player functions

* Add play_game method for backgammon

* Refactor functions

* Update argmax function call

* Fixed errors in notebooks (aimacode#910)

* corrected cell type

* fixed umbrella_prior not defined error

* minor changes

* [WIP] Refactor planning.py (aimacode#921)

* GraphPlan fixed

* Updated test_planning.py

* Added test for spare_tire

* Added test for graphplan

* Added shopping problem

* Added tests for shopping_problem

* Updated README.md

* Refactored planning notebook

* Completed shopping problem

* Refactors

* Updated notebook

* Updated test_planning.py

* Removed doctest temporarily

* Added planning graph image

* Added section on GraphPlan

* Updated README.md

* Removed append (aimacode#920)

* Fixes problems in mdp.py (aimacode#918)

* Added MDP2 class

* Updated loop termination condition in value_iteration

* comment in method alphabeta_search (aimacode#914)

should be '# Body of alphabeta_search:'

* Include stochastic game class and generic expectiminimax (aimacode#916)

* Add stochastic game class

* Update backgammon class

* Update Expectiminimax

* Fix lint issues

* Correct compute_utility function

* Minor update to planning.py (aimacode#923)

* PDDLs and Actions can now be defined using Exprs as well as Strings

* Minor refactors

* Minor refactor on a variable name (aimacode#925)

* Added a line to child node

`child_node` method of `Node` uses the `problem.result` which returns normally a state not a node according to its docstring in `Problem`. Naming the variable `next_node` can be confusing to users when it actually refers to a resulting state.

* Update search.py

* Update search.py

* Minor refactors (aimacode#924)

* Refactored HLA

* Refactors

* Refactored broken tests

* Cleaned up duplicated code

* Cleaned up duplicated code

* Added TotalOrderPlanner

* Linearize helper function

* Added tests for TotalOrderPlanner

* Readd sussman anomaly test

* Added Logarithmic Naive Bayes Learner. (aimacode#928)

* test case for zebra problem

* Revert "Merge remote-tracking branch 'upstream/master'"

This reverts commit 5ceab1a, reversing
changes made to 34997e4.

* discarded HEAD changes for merge

* added ensemble_learner jpeg

* updated travis and search

* Added logarithmic learner in nlp_apps (aimacode#890)

* Remove zebra tests

* revised Bayes learner explanation

* added missing SimpleReflexAgent from upstream

* Added PartialOrderPlanner (aimacode#927)

* Added PartialOrderPlanner

* Added doctests

* Fix doctests

* Added tests for PartialOrderPlanner methods

* Added test for PartialOrderPlanner

* Rerun planning.ipynb

* Added notebook section for TotalOrderPlanner

* Added image

* Added notebook section for PartialOrderPlanner

* Updated README.md

* Refactor double tennis problem

* Refactored test for double_tennis_problem

* Updated README.md

* Added notebook sections for job_shop_problem and double_tennis_problem

* Updated README.md

* Fixed refinements example

* Added go_to_sfo problem

* Rename TotalOrderPlanner

* Renamed PDDL to PlanningProblem

* Added POMDP-value-iteration (aimacode#929)

* Added POMDP value iteration

* Added plot_pomdp_utility function

* Added tests for pomdp-value-iteration

* Updated README.md

* Fixed notebook import

* Changed colors

* Added notebook sections for POMDP and pomdp_value_iteration

* Fixed notebook parsing error

* Replace pomdp.ipynb

* Updated README.md

* Fixed line endings

* Fixed line endings

* Fixed line endings

* Fixed line endings

* Removed numpy dependency

* Added docstrings

* Fix tests

* Added a test for pomdp_value_iteration

* Remove numpy dependencies from mdp.ipynb

* Added POMDP to mdp_apps.ipynb

* Information Gathering Agent and probability notebook update (aimacode#931)

* Formatting fixes

* Added runtime comparisons of algorithms

* Added tests

* Updated README.md

* Added HMM explanation and contents tab

* Added section on fixed lag smoothing

* Added notebook sections on particle filtering and monte carlo localization

* Updated README.md

* Minor formatting fix

* Added decision networks and information gathering agent

* Added notebook sections for decision networks and information gathering agent

* Updated README.md

* minor spacing

* more minor spacing

* Angelic_search (aimacode#940)

* Added angelic search to planning code

* Added unit tests for angelic search

* Created notebook planning_angelic_search.ipynb

* Fixed refinements function for HLAs

* Hierarchical (aimacode#943)

* created notebooks for GraphPlan, Total Order Planner and Partial Order Planner

* Added hierarchical search and tests

* Created notebook planning_hierarchical_search.ipynb

* Added making progress and tests, minor changes in decompose

* image for planning_hierarchical_search.ipynb

* Updated the status of angelic_search and hierarchical_search.

* Notebook updates (aimacode#942)

* Added notebook section for DTAgentProgram

* Updated README.md

* Minor

* Added TODO to fix pomdp tests

* Added notebook section on AC3

* Added doctests to agents.py

* Fixed pomdp tests

* Fixed a doctest

* Fixed pomdp test

* Added doctests for rl.py

* Fixed NameError in rl.py doctests

* Fixed NameError in rl.py doctests

* Minor fixes

* Minor fixes

* Fixed ImportErrors

* Fixed all doctests

* Search notebook update (aimacode#933)

* Added tests for online dfs agent

* Minor formatting fixes

* Completed notebook sections

* Updated README.md

* Fixed a test

* Added new algorithms to display_visual notebook function

* Added RBFS visualization

* Foil (aimacode#946)

* Modified FOIL_container

* Added unit tests for FOIL_container functions

* Added knowledge_current_best notebook

* Added knowledge_FOIL notebook

* Added knowledge_version_space notebook

* Added images for knowledge_FOIL notebook

* knowledge.ipynb replaced by knowledge_current_best.ipynb, knowledge_version_space.ipynb, knowledge_FOIL.ipynb

* modify knowledge.py

* Updated FOIL entry.

* Minor modifications in planning_angelic_search.ipynb and knowledge_FOIL.ipynb notebooks (aimacode#949)

* Minor modifications in planning_angelic_search.ipynb and knowledge_FOIL.ipynb notebooks.

* added matplotlib to requirements.txt

* Update requirements.txt

* Update requirements.txt

* Update requirements.txt

* Logic notebook update (aimacode#932)

* Added KB_AgentProgram and subst

* Added doctests

* Updated README.md

* Fixed doctest

* Fixed doctest

* Fixed doctest

* Added definite_clauses_KB to logic.py

* Fixed a doctest, again

* Fixed another doctest

* Fixed another doctest

* Moved unnecessary doctests to unit tests

* Added unit test for ModelBasedReflexAgent

* Added unit test for ModelBasedReflexAgent

* Updated README.md

* Minor fix

* Fixed a doctest

* Update README.md

* Remove unnecessary goal test in search.py (aimacode#953)

Remove unnecessary initial goal test in best_first_graph_search. The loop will catch that case immediately.

* Minor Changes in Text (aimacode#955)

* Minor text change (aimacode#957)

To make it more accurate.

* Minor change in text (aimacode#956)

To make it more descriptive and accurate.

* Added relu Activation (aimacode#960)

* added relu activation

* added default parameters

* Changes in texts (aimacode#959)

Added a few new sentences, modified the sentence structure at a few places, and corrected some grammatical errors.

* Change PriorityQueue expansion (aimacode#962)

`self.heap.append` simply appends to the end of the `self.heap` 
Since `self.heap` is just a python list. 
`self.append` calls the append method of the class instance, effectively putting the item in its proper place.

* added GSoC 2018 contributors

A thank you to contributors from the GSoC 2018 program!

* Revamped the notebook (aimacode#963)

* Revamped the notebook

* A few changes reversed

Changed a few things from my original PR after a review from ad71.

* Text Changes + Colored Table (aimacode#964)

Made a colored table to display dog movement instead. Corrected grammatical errors, improved the sentence structure and corrected any typos found.

* Fixed typos (aimacode#970)

Typos and minor other text errors removed

* Fixed Typos (aimacode#971)

Corrected typos + minor other text changes

* Update intro.ipynb (aimacode#969)

* Added activation functions (aimacode#968)

* Updated label_queen_conflicts function (aimacode#967)

Shortened it, finding conflicts separately and storing them in different variables has no use later in the notebook; so i believe this looks better.

* Removed the Assignment of a variable to itself (aimacode#976)

* activate pruning inside `forward_checking` (aimacode#975)

Otherwise `csp.curr_domains` may not be available for the loop that follows.

* Fixed aimacode#972 (aimacode#973)

* usa missing AZ (Arizona) as neighbor to NM (new mexico) (aimacode#977)

`usa` in csp.py incorrectly has NM not being a neighbor with AZ.

* Added more examples (aimacode#979)

* Fixed small errors (aimacode#987)

* fixing broken links

* solved a typo in nlp.ipynb (aimacode#993)

* updating submodule (aimacode#994)

* Fix typos for Wupus agent (aimacode#999)

* Fix typos for Wupus agent

* fix imports

* Grammar and typo fixes in logic notebook (aimacode#1002)

* Update utils.py

* fixed typo

* some typos in agents file (aimacode#1008)

* some typos in utils.py (aimacode#1017)

* Added some test cases to first function in utils.py (aimacode#1016)

* added some test cases to first function in utils.py

* added space after each comma

* Updated the count function in utils.py (aimacode#1013)

* improved the count function in utils.py

* updated according to PEP style

* Updated the sequence function and added test cases (aimacode#1012)

* updated the sequence function and added test cases

* updated according to the PEP style

* update in multimap function in utils.py and added test for it (aimacode#1014)

* update in multimap functi n in utils.py and added test for it

* made changes according to PEP style

* broke the long sentence to 2 shorter sentences

* necessary change in learning.py file  (aimacode#1011)

* no need of if else

* no need of if - else .   

As if hidden_layer_sizes is zero then it will not affect layer_sizes

* removed comment

* Update learning.py

* Fixed a typo in README (pl_fc_entails) (aimacode#1022)

* Shuffling data before k-fold loop in cross validation. (aimacode#1028)

* Rename search-4e.ipynb to obsolete-search-4e.ipynb

* Add files via upload

* Add files via upload

* Add files via upload

* Add files via upload

* Add files via upload

* some optimizations in knowledge.py (aimacode#1034)

* Add files via upload

* Update in `NeuralNetLearner` function in `learnign.py` (aimacode#1019)

* Update in NeuralNetLearner function

* made the changes as suggested

* Install dependencies from `requirements.txt` missing in `README.md` (aimacode#1039)

* update in Readme.md

* updated as per the suggestions in the review.

* typo

* Reworked PriorityQueue and Added Tests (aimacode#1025)

* Reworked PriorityQueue spec

Modified:
- Priority Queue methods:
    queue[elem] now returns the first value of elem stored in queue
    elem in queue now correctly returns whether a copy of element is present regardless of the function value. Apparently the bug was introduced while trying to meet heapq spec
    del queue[elem] deletes the first instance of elem in queue correctly
- Algorithms
    Same change in best_first_graph_search in romania_problem.py and search.py to make them compatible with the new spec
- Tests
    Introduced 3 tests in test_utils.py to comprehensively test PriorityQueue's new spec

* Reworked PriorityQueue spec

Modified:
- Priority Queue methods:
    queue[elem] now returns the first value of elem stored in queue
    elem in queue now correctly returns whether a copy of element is present regardless of the function value. Apparently the bug was introduced while trying to meet heapq spec
    del queue[elem] deletes the first instance of elem in queue correctly
- Algorithms
    Same change in best_first_graph_search in romania_problem.py and search.py to make them compatible with the new spec
- Tests
    Introduced 3 tests in test_utils.py to comprehensively test PriorityQueue's new spec

* closing the old cell window (aimacode#996)

* Add files via upload

* changed queue to set in AC3 (aimacode#1051)

* changed queue to set in AC3

Changed queue to set in AC3 (as in the pseudocode of the original algorithm) to reduce the number of consistency-check due to the redundancy of the same arcs in queue. For example, on the harder1 configuration of the Sudoku CSP the number consistency-check has been reduced from 40464 to 12562!

* re-added test commented by mistake

* Rework agents.ipynb (aimacode#1031)

* Reworked Introduction and 1-D environment in agents.py

Added:
 - Table of Contents and overview
 - A miniscule explanation of all required code from agents.py
Modified:
 - Some grammar and sentences
 - Structure of the notebook in 1-D environments to make it more coherent
Removed:
 - Outputs from notebook (Makes VCS tough and bugs tough to detect)

* Reworked agents in a 2D environment

Modified:
 - Removed global variable turn from 2D park model: Agent programs are not supposed to see anything except percepts
 - Bump percept is now generated when Dog is about to bump into a wall
 - Replaced all XYEnvironment with GraphicEnvironment - Gives better readability to both code and output (Previous way of just showing GraphicEnvironment in the end was redundant imo)
 - Restructured the 2D park and EnergeticBlindDog environment scenario to be more readable
Removed:
 - Redundant Park2D without graphics (subclass of XYEnvironment)

* Fixed issue aimacode#1030

Added:
 - ipython and ipythonblocks packages to requirements.txt

* Has some typographic improvements in agents.ipynb

* Added output to agents.ipynb

* The function truncated_svd() should not return negative singular values. (aimacode#1059)

* Added test cases for agents.py (aimacode#1057)

* Added WumpusWorld testcases

Added:
 - Testcases in test_agents.py
Modified:
 - Duplicate walls are not added in corners now

* Tests for VacuumEnvironment and WumpusEnvironment

Added:
 - Test cases for Explorer actions in WumpusEnvironment
 - Test cases for VacuumEnvironment
Modified:
 - VacuumAgent correctly disables bump percept when agent sucks dirt after bumping into a wall

* Added spaces in tuples to comply with PEP8

* Updates and changes required in CONTRIBUTING.md (aimacode#1055)

* Update GSOC link to correctly refer aimacode@GSOC2019

* Correct the underlying typo

* Update CONTRIBUTING.md (aimacode#1063)

Update CONTRIBUTING.md

* Improvement in train_test_split function (aimacode#1067)

Improvement in train_test_split function

Shuffling has been removed

* style fixes

* added necessary and unique tests (aimacode#1071)

* added necessary and unique tests

* some required changes

* required changes

* Add files via upload

* Update test_csp.py (issue aimacode#287) (aimacode#1073)

Cover or use at least once in tests classes, methods, and non-debugging functions of csp.py (version 18.04.2019).  Issue aimacode#287.

* added text classification in nlp_apps (aimacode#1043)

* added text classification in nlp_apps

* updated as per the changes suggested.

* Update learning.py

* Bruyang (aimacode#1075)

* add monte carlo tree search

* add comments to mcts

* change model based reflex agent

* add games4e.py

* recover games4e.ipynb

* add tests to mcts

* Added coverage report generation to Travis (aimacode#1058)

Added:
 - .coveragerc file to configure report generation
Modified:
 - .travis.yml to start generating reports during build

* added class Tfidf (aimacode#1054)

* Implementing Class Tfidf

* added class of Tfidf
* added scoring function BM25

* Revert "Implementing Class Tfidf"

Remove unnecessary initial goal test in best_first_graph_search. The loop will catch that case immediately.