gemseo_matlab

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engine module

Definition of the matlab engine singleton for workspace handling.

Overview

This module contains the MatlabEngine class which enables to build the Matlab workspace. The Matlab workspace must be seen as the Matlab “area” where Matlab functions are executed as well as Matlab variables live. The engine is basically used when creating a MatlabDiscipline instance and therefore is not directly handled by the user. However, a MatlabEngine instance can be used outside a MatlabDiscipline in order to directly call Matlab functions and/or accessing to some variables into the Matlab workspace.

Since MatlabEngine is private, it cannot be used directly from the module. It is rather used through the function get_matlab_engine() which enables to create only one instance with respect to the workspace_name (i.e. the instance is unique if the workspace name is the same when calling several times the function). Following this, MatlabEngine acts like a singleton.

class gemseo_matlab.engine.MatlabEngine(engine_name)[source]

Bases: object

Wrapper around the matlab execution engine.

Since this class is private, an instance should be built through get_matlab_engine() function. Using that latter function acts like a singleton, i.e. the returned instance is unique if the workspace name is the same.

Examples

>>> eng1 = get_matlab_engine()
>>> # add new searching directory to workspace with sub-dir
>>> eng1.add_path("dir_to_files", add_subfolder=True)
>>>
>>> # check if a function exists in workspace and returns the type
>>> exist, type_func = eng1.exist("cos")
>>> # execute the function
>>> eng1.execute_function("cos", 0, nargout=1)
>>>
>>> # quit engine
>>> eng1.close_session()
>>> print(eng1.is_closed)
Parameters:

engine_name (str) – The name identifying the engine.

class ParallelType(value)[source]

Bases: StrEnum

Types of Matlab parallel execution.

capitalize()

Return a capitalized version of the string.

More specifically, make the first character have upper case and the rest lower case.

casefold()

Return a version of the string suitable for caseless comparisons.

center(width, fillchar=' ', /)

Return a centered string of length width.

Padding is done using the specified fill character (default is a space).

count(sub[, start[, end]]) int

Return the number of non-overlapping occurrences of substring sub in string S[start:end]. Optional arguments start and end are interpreted as in slice notation.

encode(encoding='utf-8', errors='strict')

Encode the string using the codec registered for encoding.

encoding

The encoding in which to encode the string.

errors

The error handling scheme to use for encoding errors. The default is ‘strict’ meaning that encoding errors raise a UnicodeEncodeError. Other possible values are ‘ignore’, ‘replace’ and ‘xmlcharrefreplace’ as well as any other name registered with codecs.register_error that can handle UnicodeEncodeErrors.

endswith(suffix[, start[, end]]) bool

Return True if S ends with the specified suffix, False otherwise. With optional start, test S beginning at that position. With optional end, stop comparing S at that position. suffix can also be a tuple of strings to try.

expandtabs(tabsize=8)

Return a copy where all tab characters are expanded using spaces.

If tabsize is not given, a tab size of 8 characters is assumed.

find(sub[, start[, end]]) int

Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation.

Return -1 on failure.

format(*args, **kwargs) str

Return a formatted version of S, using substitutions from args and kwargs. The substitutions are identified by braces (‘{’ and ‘}’).

format_map(mapping) str

Return a formatted version of S, using substitutions from mapping. The substitutions are identified by braces (‘{’ and ‘}’).

index(sub[, start[, end]]) int

Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation.

Raises ValueError when the substring is not found.

isalnum()

Return True if the string is an alpha-numeric string, False otherwise.

A string is alpha-numeric if all characters in the string are alpha-numeric and there is at least one character in the string.

isalpha()

Return True if the string is an alphabetic string, False otherwise.

A string is alphabetic if all characters in the string are alphabetic and there is at least one character in the string.

isascii()

Return True if all characters in the string are ASCII, False otherwise.

ASCII characters have code points in the range U+0000-U+007F. Empty string is ASCII too.

isdecimal()

Return True if the string is a decimal string, False otherwise.

A string is a decimal string if all characters in the string are decimal and there is at least one character in the string.

isdigit()

Return True if the string is a digit string, False otherwise.

A string is a digit string if all characters in the string are digits and there is at least one character in the string.

isidentifier()

Return True if the string is a valid Python identifier, False otherwise.

Call keyword.iskeyword(s) to test whether string s is a reserved identifier, such as “def” or “class”.

islower()

Return True if the string is a lowercase string, False otherwise.

A string is lowercase if all cased characters in the string are lowercase and there is at least one cased character in the string.

isnumeric()

Return True if the string is a numeric string, False otherwise.

A string is numeric if all characters in the string are numeric and there is at least one character in the string.

isprintable()

Return True if the string is printable, False otherwise.

A string is printable if all of its characters are considered printable in repr() or if it is empty.

isspace()

Return True if the string is a whitespace string, False otherwise.

A string is whitespace if all characters in the string are whitespace and there is at least one character in the string.

istitle()

Return True if the string is a title-cased string, False otherwise.

In a title-cased string, upper- and title-case characters may only follow uncased characters and lowercase characters only cased ones.

isupper()

Return True if the string is an uppercase string, False otherwise.

A string is uppercase if all cased characters in the string are uppercase and there is at least one cased character in the string.

join(iterable, /)

Concatenate any number of strings.

The string whose method is called is inserted in between each given string. The result is returned as a new string.

Example: ‘.’.join([‘ab’, ‘pq’, ‘rs’]) -> ‘ab.pq.rs’

ljust(width, fillchar=' ', /)

Return a left-justified string of length width.

Padding is done using the specified fill character (default is a space).

lower()

Return a copy of the string converted to lowercase.

lstrip(chars=None, /)

Return a copy of the string with leading whitespace removed.

If chars is given and not None, remove characters in chars instead.

static maketrans()

Return a translation table usable for str.translate().

If there is only one argument, it must be a dictionary mapping Unicode ordinals (integers) or characters to Unicode ordinals, strings or None. Character keys will be then converted to ordinals. If there are two arguments, they must be strings of equal length, and in the resulting dictionary, each character in x will be mapped to the character at the same position in y. If there is a third argument, it must be a string, whose characters will be mapped to None in the result.

partition(sep, /)

Partition the string into three parts using the given separator.

This will search for the separator in the string. If the separator is found, returns a 3-tuple containing the part before the separator, the separator itself, and the part after it.

If the separator is not found, returns a 3-tuple containing the original string and two empty strings.

removeprefix(prefix, /)

Return a str with the given prefix string removed if present.

If the string starts with the prefix string, return string[len(prefix):]. Otherwise, return a copy of the original string.

removesuffix(suffix, /)

Return a str with the given suffix string removed if present.

If the string ends with the suffix string and that suffix is not empty, return string[:-len(suffix)]. Otherwise, return a copy of the original string.

replace(old, new, count=-1, /)

Return a copy with all occurrences of substring old replaced by new.

count

Maximum number of occurrences to replace. -1 (the default value) means replace all occurrences.

If the optional argument count is given, only the first count occurrences are replaced.

rfind(sub[, start[, end]]) int

Return the highest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation.

Return -1 on failure.

rindex(sub[, start[, end]]) int

Return the highest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation.

Raises ValueError when the substring is not found.

rjust(width, fillchar=' ', /)

Return a right-justified string of length width.

Padding is done using the specified fill character (default is a space).

rpartition(sep, /)

Partition the string into three parts using the given separator.

This will search for the separator in the string, starting at the end. If the separator is found, returns a 3-tuple containing the part before the separator, the separator itself, and the part after it.

If the separator is not found, returns a 3-tuple containing two empty strings and the original string.

rsplit(sep=None, maxsplit=-1)

Return a list of the words in the string, using sep as the delimiter string.

sep

The delimiter according which to split the string. None (the default value) means split according to any whitespace, and discard empty strings from the result.

maxsplit

Maximum number of splits to do. -1 (the default value) means no limit.

Splits are done starting at the end of the string and working to the front.

rstrip(chars=None, /)

Return a copy of the string with trailing whitespace removed.

If chars is given and not None, remove characters in chars instead.

split(sep=None, maxsplit=-1)

Return a list of the words in the string, using sep as the delimiter string.

sep

The delimiter according which to split the string. None (the default value) means split according to any whitespace, and discard empty strings from the result.

maxsplit

Maximum number of splits to do. -1 (the default value) means no limit.

splitlines(keepends=False)

Return a list of the lines in the string, breaking at line boundaries.

Line breaks are not included in the resulting list unless keepends is given and true.

startswith(prefix[, start[, end]]) bool

Return True if S starts with the specified prefix, False otherwise. With optional start, test S beginning at that position. With optional end, stop comparing S at that position. prefix can also be a tuple of strings to try.

strip(chars=None, /)

Return a copy of the string with leading and trailing whitespace removed.

If chars is given and not None, remove characters in chars instead.

swapcase()

Convert uppercase characters to lowercase and lowercase characters to uppercase.

title()

Return a version of the string where each word is titlecased.

More specifically, words start with uppercased characters and all remaining cased characters have lower case.

translate(table, /)

Replace each character in the string using the given translation table.

table

Translation table, which must be a mapping of Unicode ordinals to Unicode ordinals, strings, or None.

The table must implement lookup/indexing via __getitem__, for instance a dictionary or list. If this operation raises LookupError, the character is left untouched. Characters mapped to None are deleted.

upper()

Return a copy of the string converted to uppercase.

zfill(width, /)

Pad a numeric string with zeros on the left, to fill a field of the given width.

The string is never truncated.

CLOUD = 'MATLAB Parallel Cloud'
LOCAL = 'local'
add_path(path, add_subfolder=False)[source]

Add a path to the matlab engine search directories.

Parameters:
  • path (str | Path) – The path to the directory or file to be added to path.

  • add_subfolder (bool) –

    Whether to add the sub-folders recursively.

    By default it is set to False.

Raises:

ValueError – If the given path cannot be added to Matlab.

Return type:

None

add_toolbox(toolbox_name)[source]

Add a toolbox to the engine.

The toolbox added would be needed for the functions used in the current session. It should be checked that the license is compatible. The name given here can be found using “license(‘inuse’)” in MATLAB.

Parameters:

toolbox_name (str) – The name of the toolbox to be checked.

Return type:

None

close_session()[source]

Close the matlab session.

Return type:

None

end_parallel_computing()[source]

End the parallel computing.

Raises:

matlab.engine.MatlabExecutionError – If the parallel option is not correctly deactivated.

Return type:

None

execute_function(func_name, *args, **kwargs)[source]

Executes a Matlab function called “func_name”.

Parameters:
  • func_name (str) – The function name to call.

  • *args (float | str) – Any arguments that must be passed to the function.

  • **kwargs (float) – Any arguments that must be passed to the function.

Raises:

matlab.engine.MatlabExecutionError – If the matlab function execution fails.

Return type:

Any

execute_script(script_name)[source]

Execute a script in the current workspace.

After executing the script, the workspace point to the path where the script is located.

Parameters:

script_name (str) – The script name.

Return type:

None

exist(name)[source]

Check if the given matlab file exists.

Parameters:

name (str | Path) – The name to be checked if present in MATLAB path.

Returns:

A boolean that tells if name exist. A string that indicates the type of file where function_name is found.

Return type:

tuple[bool, str]

get_toolboxes()[source]

Return all toolboxes to be checked before launching this engine.

Returns:

All toolboxes.

Return type:

set[str]

get_variable(item)[source]

Get any variable in the workspace.

Parameters:

item (str) – The variable name.

Returns:

The value of the variable.

Raises:

ValueError – If the item is unknown inside the workspace.

Return type:

ndarray

remove_toolbox(toolbox_name)[source]

Remove a toolbox from the engine.

Parameters:

toolbox_name (str) – The name of the toolbox to be checked.

Return type:

None

start_engine()[source]

Start the matlab engine.

Return type:

None

start_parallel_computing(n_parallel_workers, parallel_type=ParallelType.LOCAL)[source]

Start the parallel pool of matlab for parallel computing.

This feature only works if parallel toolbox is available.

Parameters:
  • n_parallel_workers (int) – The number of “workers” to the parallel pool.

  • parallel_type (ParallelType) –

    The type of parallel execution.

    By default it is set to “local”.

Return type:

None

property engine_name: str

The engine name.

property is_closed: bool

Return True if the matlab engine is closed.

property is_parallel: bool

Return True if parallel is active.

property paths: list[str]

Return the paths.

gemseo_matlab.engine.get_matlab_engine(workspace_name='matlab')[source]

Return a new matlab engine.

LRU cache decorator enables to cache the instance if prescribed workspace_name is the same. Therefore, it acts like a singleton. This means that calling this function with the same workspace_name returns the same instance.

Parameters:

workspace_name (str) –

The name of matlab workspace.

By default it is set to “matlab”.

Returns:

A Matlab engine instance.

Return type:

MatlabEngine

Examples

>>> eng1 = get_matlab_engine()
>>> eng2 = get_matlab_engine()
>>> # make sure that engines are the same
>>> eng1 is eng2