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Dynamic programming/matrix chain multiplication #10562

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merged 11 commits into from
Oct 15, 2023

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Shailaputri
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Describe your change:

  • Add an algorithm?
  • Fix a bug or typo in an existing algorithm?
  • Documentation change?

Checklist:

  • I have read CONTRIBUTING.md.
  • This pull request is all my own work -- I have not plagiarized.
  • I know that pull requests will not be merged if they fail the automated tests.
  • This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
  • All new Python files are placed inside an existing directory.
  • All filenames are in all lowercase characters with no spaces or dashes.
  • All functions and variable names follow Python naming conventions.
  • All function parameters and return values are annotated with Python type hints.
  • All functions have doctests that pass the automated testing.
  • All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
  • If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

P.s. I would like to add that I started by trying to add doctests to matrix_chain_order.py script under Python/dynamic_programming/matrix_chain_order in order to improve its test coverage. However, I found the functions poorly written. Instead of changing the code, I have written a separate script with bug free code, problem explanation and required doctests. Moderators may consider deleting matrix_chain_order.py. Creating new PR by deleting #10549 and #10561.

@cclauss
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cclauss commented Oct 15, 2023

When would the algorithm be used in the real-world?

@Shailaputri
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Shailaputri commented Oct 15, 2023

Adding some real world applications of the algorithm in docstring.

@algorithms-keeper algorithms-keeper bot added the awaiting reviews This PR is ready to be reviewed label Oct 15, 2023
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Do you have an implementation of the algorithm for determining the actual order of multiplications? Simply knowing how many operations are needed isn't very useful and doesn't help with any of the real-world applications.

dynamic_programming/matrix_chain_multiplication.py Outdated Show resolved Hide resolved
Add a non-dp solution with benchmarks.
@algorithms-keeper algorithms-keeper bot added require descriptive names This PR needs descriptive function and/or variable names require tests Tests [doctest/unittest/pytest] are required require type hints https://docs.python.org/3/library/typing.html labels Oct 15, 2023
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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function a

Please provide return type hint for the function: a. If the function does not return a value, please provide the type hint as: def function() -> None:

Please provide descriptive name for the function: a

Please provide type hint for the parameter: i

Please provide descriptive name for the parameter: i

Please provide type hint for the parameter: j

Please provide descriptive name for the parameter: j



@contextmanager
def elapsed_time(msg: str) -> None:

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function elapsed_time

@algorithms-keeper algorithms-keeper bot added the tests are failing Do not merge until tests pass label Oct 15, 2023
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Click here to look at the relevant links ⬇️

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"""

@cache
def a(i, j):

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function a

Please provide return type hint for the function: a. If the function does not return a value, please provide the type hint as: def function() -> None:

Please provide descriptive name for the function: a

Please provide type hint for the parameter: i

Please provide descriptive name for the parameter: i

Please provide type hint for the parameter: j

Please provide descriptive name for the parameter: j



@contextmanager
def elapsed_time(msg: str) -> Iterator:

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function elapsed_time

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Click here to look at the relevant links ⬇️

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Repository:

Python:

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"""

@cache
def a(i, j):

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function a

Please provide return type hint for the function: a. If the function does not return a value, please provide the type hint as: def function() -> None:

Please provide descriptive name for the function: a

Please provide type hint for the parameter: i

Please provide descriptive name for the parameter: i

Please provide type hint for the parameter: j

Please provide descriptive name for the parameter: j



@contextmanager
def elapsed_time(msg: str) -> Iterator:

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function elapsed_time

@algorithms-keeper algorithms-keeper bot removed the tests are failing Do not merge until tests pass label Oct 15, 2023
@algorithms-keeper algorithms-keeper bot removed the require type hints https://docs.python.org/3/library/typing.html label Oct 15, 2023
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Click here to look at the relevant links ⬇️

🔗 Relevant Links

Repository:

Python:

Automated review generated by algorithms-keeper. If there's any problem regarding this review, please open an issue about it.

algorithms-keeper commands and options

algorithms-keeper actions can be triggered by commenting on this PR:

  • @algorithms-keeper review to trigger the checks for only added pull request files
  • @algorithms-keeper review-all to trigger the checks for all the pull request files, including the modified files. As we cannot post review comments on lines not part of the diff, this command will post all the messages in one comment.

NOTE: Commands are in beta and so this feature is restricted only to a member or owner of the organization.

"""

@cache
def a(i: int, j: int) -> int:

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function a

Please provide descriptive name for the function: a

Please provide descriptive name for the parameter: i

Please provide descriptive name for the parameter: j



@contextmanager
def elapsed_time(msg: str) -> Iterator:

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As there is no test file in this pull request nor any test function or class in the file dynamic_programming/matrix_chain_multiplication.py, please provide doctest for the function elapsed_time

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The algorithm is framed in the same way on Wikipedia. There are two different algorithms with benchmarks.

@algorithms-keeper algorithms-keeper bot removed the awaiting reviews This PR is ready to be reviewed label Oct 15, 2023
@cclauss cclauss enabled auto-merge (squash) October 15, 2023 23:32
@cclauss cclauss dismissed tianyizheng02’s stale review October 15, 2023 23:32

The algorithm is framed in the same way on Wikipedia. There are two different algorithms with benchmarks.

@cclauss cclauss merged commit e6aae1c into TheAlgorithms:master Oct 15, 2023
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3 participants