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Symbol Library Module

SRToolkit.utils.symbol_library

This module contains the SymbolLibrary class, which is used for managing symbols and their properties.

SymbolLibrary

Source code in SRToolkit/utils/symbol_library.py 
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class SymbolLibrary:
    def __init__(self):
        """
        Initializes an instance of the SymbolLibrary class. This class is used for managing symbols and their
        properties for other functionality in this package.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.get_type("x")
            'var'
            >>> library.get_precedence("x")
            0
            >>> library.get_np_fn("x")
            'x'
            >>> library.remove_symbol("x")
            >>> library = SymbolLibrary.default_symbols()

        Attributes:
            symbols : dict
                A dictionary mapping symbols to their properties (type, precedence, numpy function).

        Methods:
            add_symbol(symbol, symbol_type, precedence, np_fn):
                Adds a symbol to the library.
            remove_symbol(symbol):
                Removes a symbol from the library.
            get_type(symbol):
                Retrieves the type of a symbol from the library.
            get_precedence(symbol):
                Returns the precedence of the given symbol.
            get_np_fn(symbol):
                Returns the numpy function corresponding to the given symbol.
            default_symbols():
                Returns a SymbolLibrary with the default symbols.
        """
        self.symbols = dict()

    def __str__(self) -> str:
        """
        Returns a string representation of the SymbolLibrary instance.

        This method provides a comma-separated string of all the symbol keys
        currently stored in the SymbolLibrary.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> str(library)
            'x'
            >>> library.add_symbol("sin", "fn", 5, "{} = np.sin({})")
            >>> str(library)
            'x, sin'

        Returns:
            A string containing all symbols in the library, separated by commas.
        """
        return ", ".join(self.symbols.keys())

    def __copy__(self) -> "SymbolLibrary":
        """
        Creates a copy of the SymbolLibrary instance.

        Examples:
            >>> old_symbols = SymbolLibrary()
            >>> old_symbols.add_symbol("x", "var", 0, "x")
            >>> print(old_symbols)
            x
            >>> new_symbols = copy.copy(old_symbols)
            >>> new_symbols.add_symbol("sin", "fn", 5, "{} = np.sin({})")
            >>> print(old_symbols)
            x
            >>> print(new_symbols)
            x, sin

        Returns:
            A copy of the SymbolLibrary instance.
        """
        sl = SymbolLibrary()
        sl.symbols = copy.deepcopy(self.symbols)
        return sl

    def add_symbol(self, symbol: str, symbol_type: str, precedence: int, np_fn: str):
        """
        Adds a symbol to the library. A symbol should have a type, precedence, and numpy function associated with it.
        Type "op" should be used for symbols operating on two operands, "fn" for symbols operating on one operand,
        "lit" for constants with a known value (such as pi or e), "const" for constants/parameters without a value that
        need to be optimized, and "var" for variables whose values are provided as input data.

        For example, look at the default_symbols function for the SymbolLibrary class.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.add_symbol("sin", "fn", 5, "np.sin({})")
            >>> library.add_symbol("C", "const", 5, "C[{}]")
            >>> library.add_symbol("X", "var", 5, "X[:, 0]")
            >>> library.add_symbol("pi", "lit", 5, "np.pi")

        Args:
            symbol: The symbol to be added to the library.
            symbol_type: The type of the symbol, one of "op" (operator), "fn" (function), "lit" (literal), "const" (constant), or "var" (variable).
            precedence: The precedence of the symbol, used to determine the order of operations.
            np_fn: A string representing the numpy function associated with this symbol.
        """
        self.symbols[symbol] = {
            "symbol": symbol,
            "type": symbol_type,
            "precedence": precedence,
            "np_fn": np_fn,
        }

    def remove_symbol(self, symbol: str):
        """
        Removes a symbol from the library.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> len(library.symbols)
            1
            >>> library.remove_symbol("x")
            >>> len(library.symbols)
            0

        Args:
            symbol: The symbol to be removed from the library.

        Raises:
            KeyError: If the symbol does not exist in the library.
        """
        del self.symbols[symbol]

    def get_type(self, symbol: str) -> str:
        """
        Retrieves the type of a symbol from the library.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.get_type("x")
            'var'

        Args:
            symbol: The symbol whose type is to be retrieved.

        Returns:
            The type of the symbol if it exists in the library, otherwise an empty string.
        """
        if symbol in self.symbols:
            return self.symbols[symbol]["type"]
        else:
            return ""

    def get_precedence(self, symbol: str) -> int:
        """
        Retrieves the precedence of the given symbol.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.get_precedence("x")
            0

        Args:
            symbol: The symbol whose precedence is to be retrieved.

        Returns:
            The precedence of the symbol if it exists in the library, otherwise -1.
        """
        if symbol in self.symbols:
            return self.symbols[symbol]["precedence"]
        else:
            return -1

    def get_np_fn(self, symbol: str) -> str:
        """
        Returns the numpy function corresponding to the given symbol.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.get_np_fn("x")
            'x'

        Args:
            symbol: The symbol to look up.

        Returns:
            The numpy function corresponding to the given symbol, or an empty string if the symbol was not found.
        """
        if symbol in self.symbols:
            return self.symbols[symbol]["np_fn"]
        else:
            return ""

    @staticmethod
    def default_symbols(num_variables: int = 25) -> "SymbolLibrary":
        """
        Creates a SymbolLibrary instance populated with default mathematical symbols.

        This method adds a set of predefined symbols to a SymbolLibrary instance,
        representing common mathematical operations, functions, constants, and optional
        variables. The symbols include basic arithmetic operations, trigonometric and
        exponential functions, and mathematical constants like pi and e.

        If num_variables is greater than 0, it adds variables labeled 'X_0' to 'X_{num_variables-1}', each
         associated with a column in a data array X.

        Note: The variables in the default_symbols function are added in the predefined order,
        which is the same order as the columns in the data array X.

        Examples:
            >>> library = SymbolLibrary.default_symbols()
            >>> len(library.symbols)
            44

        Args:
            num_variables: The number of variables to add to the library (default is 25).

        Returns:
            A SymbolLibrary instance populated with default mathematical symbols.
        """
        sl = SymbolLibrary()
        sl.add_symbol("+", symbol_type="op", precedence=0, np_fn="{} = {} + {}")
        sl.add_symbol("-", symbol_type="op", precedence=0, np_fn="{} = {} - {}")
        sl.add_symbol("*", symbol_type="op", precedence=1, np_fn="{} = {} * {}")
        sl.add_symbol("/", symbol_type="op", precedence=1, np_fn="{} = {} / {}")
        sl.add_symbol("^", symbol_type="op", precedence=2, np_fn="{} = np.pow({},{})")
        sl.add_symbol("u-", symbol_type="fn", precedence=5, np_fn="{} = -{}")
        sl.add_symbol("sqrt", symbol_type="fn", precedence=5, np_fn="{} = np.sqrt({})")
        sl.add_symbol("sin", symbol_type="fn", precedence=5, np_fn="{} = np.sin({})")
        sl.add_symbol("cos", symbol_type="fn", precedence=5, np_fn="{} = np.cos({})")
        sl.add_symbol("exp", symbol_type="fn", precedence=5, np_fn="{} = np.exp({})")
        sl.add_symbol("ln", symbol_type="fn", precedence=5, np_fn="{} = np.log({})")
        sl.add_symbol("log", symbol_type="fn", precedence=5, np_fn="{} = np.log10({})")
        sl.add_symbol("^-1", symbol_type="fn", precedence=-1, np_fn="{} = 1/{}")
        sl.add_symbol("^2", symbol_type="fn", precedence=-1, np_fn="{} = {}**2")
        sl.add_symbol("^3", symbol_type="fn", precedence=-1, np_fn="{} = {}**3")
        sl.add_symbol("^4", symbol_type="fn", precedence=-1, np_fn="{} = {}**4")
        sl.add_symbol("^5", symbol_type="fn", precedence=-1, np_fn="{} = {}**5")
        sl.add_symbol("pi", symbol_type="lit", precedence=5, np_fn="np.pi")
        sl.add_symbol("e", symbol_type="lit", precedence=5, np_fn="np.e")
        sl.add_symbol("C", symbol_type="const", precedence=5, np_fn="C[{}]")

        if num_variables > 0:
            for i in range(num_variables):
                sl.add_symbol(f"X_{i}", "var", 5, "X[:, {}]".format(i))

        return sl

__init__()

Initializes an instance of the SymbolLibrary class. This class is used for managing symbols and their properties for other functionality in this package.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.get_type("x")
'var'
>>> library.get_precedence("x")
0
>>> library.get_np_fn("x")
'x'
>>> library.remove_symbol("x")
>>> library = SymbolLibrary.default_symbols()

Attributes:

Name Type Description
symbols

dict A dictionary mapping symbols to their properties (type, precedence, numpy function).

Functions:

Name Description
add_symbol

Adds a symbol to the library.
remove_symbol

Removes a symbol from the library.
get_type

Retrieves the type of a symbol from the library.
get_precedence

Returns the precedence of the given symbol.
get_np_fn

Returns the numpy function corresponding to the given symbol.
default_symbols

Returns a SymbolLibrary with the default symbols.
Source code in SRToolkit/utils/symbol_library.py 
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def __init__(self):
    """
    Initializes an instance of the SymbolLibrary class. This class is used for managing symbols and their
    properties for other functionality in this package.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.get_type("x")
        'var'
        >>> library.get_precedence("x")
        0
        >>> library.get_np_fn("x")
        'x'
        >>> library.remove_symbol("x")
        >>> library = SymbolLibrary.default_symbols()

    Attributes:
        symbols : dict
            A dictionary mapping symbols to their properties (type, precedence, numpy function).

    Methods:
        add_symbol(symbol, symbol_type, precedence, np_fn):
            Adds a symbol to the library.
        remove_symbol(symbol):
            Removes a symbol from the library.
        get_type(symbol):
            Retrieves the type of a symbol from the library.
        get_precedence(symbol):
            Returns the precedence of the given symbol.
        get_np_fn(symbol):
            Returns the numpy function corresponding to the given symbol.
        default_symbols():
            Returns a SymbolLibrary with the default symbols.
    """
    self.symbols = dict()

__str__()

Returns a string representation of the SymbolLibrary instance.

This method provides a comma-separated string of all the symbol keys currently stored in the SymbolLibrary.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> str(library)
'x'
>>> library.add_symbol("sin", "fn", 5, "{} = np.sin({})")
>>> str(library)
'x, sin'

Returns:

Type Description
str

A string containing all symbols in the library, separated by commas.
Source code in SRToolkit/utils/symbol_library.py 
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def __str__(self) -> str:
    """
    Returns a string representation of the SymbolLibrary instance.

    This method provides a comma-separated string of all the symbol keys
    currently stored in the SymbolLibrary.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> str(library)
        'x'
        >>> library.add_symbol("sin", "fn", 5, "{} = np.sin({})")
        >>> str(library)
        'x, sin'

    Returns:
        A string containing all symbols in the library, separated by commas.
    """
    return ", ".join(self.symbols.keys())

__copy__()

Creates a copy of the SymbolLibrary instance.

Examples:

>>> old_symbols = SymbolLibrary()
>>> old_symbols.add_symbol("x", "var", 0, "x")
>>> print(old_symbols)
x
>>> new_symbols = copy.copy(old_symbols)
>>> new_symbols.add_symbol("sin", "fn", 5, "{} = np.sin({})")
>>> print(old_symbols)
x
>>> print(new_symbols)
x, sin

Returns:

Type Description
SymbolLibrary

A copy of the SymbolLibrary instance.
Source code in SRToolkit/utils/symbol_library.py 
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def __copy__(self) -> "SymbolLibrary":
    """
    Creates a copy of the SymbolLibrary instance.

    Examples:
        >>> old_symbols = SymbolLibrary()
        >>> old_symbols.add_symbol("x", "var", 0, "x")
        >>> print(old_symbols)
        x
        >>> new_symbols = copy.copy(old_symbols)
        >>> new_symbols.add_symbol("sin", "fn", 5, "{} = np.sin({})")
        >>> print(old_symbols)
        x
        >>> print(new_symbols)
        x, sin

    Returns:
        A copy of the SymbolLibrary instance.
    """
    sl = SymbolLibrary()
    sl.symbols = copy.deepcopy(self.symbols)
    return sl

add_symbol(symbol, symbol_type, precedence, np_fn)

Adds a symbol to the library. A symbol should have a type, precedence, and numpy function associated with it. Type "op" should be used for symbols operating on two operands, "fn" for symbols operating on one operand, "lit" for constants with a known value (such as pi or e), "const" for constants/parameters without a value that need to be optimized, and "var" for variables whose values are provided as input data.

For example, look at the default_symbols function for the SymbolLibrary class.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.add_symbol("sin", "fn", 5, "np.sin({})")
>>> library.add_symbol("C", "const", 5, "C[{}]")
>>> library.add_symbol("X", "var", 5, "X[:, 0]")
>>> library.add_symbol("pi", "lit", 5, "np.pi")

Parameters:

Name Type Description Default
symbol str

The symbol to be added to the library.

 required
symbol_type str

The type of the symbol, one of "op" (operator), "fn" (function), "lit" (literal), "const" (constant), or "var" (variable).

 required
precedence int

The precedence of the symbol, used to determine the order of operations.

 required
np_fn str

A string representing the numpy function associated with this symbol.

 required
Source code in SRToolkit/utils/symbol_library.py 
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def add_symbol(self, symbol: str, symbol_type: str, precedence: int, np_fn: str):
    """
    Adds a symbol to the library. A symbol should have a type, precedence, and numpy function associated with it.
    Type "op" should be used for symbols operating on two operands, "fn" for symbols operating on one operand,
    "lit" for constants with a known value (such as pi or e), "const" for constants/parameters without a value that
    need to be optimized, and "var" for variables whose values are provided as input data.

    For example, look at the default_symbols function for the SymbolLibrary class.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.add_symbol("sin", "fn", 5, "np.sin({})")
        >>> library.add_symbol("C", "const", 5, "C[{}]")
        >>> library.add_symbol("X", "var", 5, "X[:, 0]")
        >>> library.add_symbol("pi", "lit", 5, "np.pi")

    Args:
        symbol: The symbol to be added to the library.
        symbol_type: The type of the symbol, one of "op" (operator), "fn" (function), "lit" (literal), "const" (constant), or "var" (variable).
        precedence: The precedence of the symbol, used to determine the order of operations.
        np_fn: A string representing the numpy function associated with this symbol.
    """
    self.symbols[symbol] = {
        "symbol": symbol,
        "type": symbol_type,
        "precedence": precedence,
        "np_fn": np_fn,
    }

remove_symbol(symbol)

Removes a symbol from the library.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> len(library.symbols)
1
>>> library.remove_symbol("x")
>>> len(library.symbols)
0

Parameters:

Name Type Description Default
symbol str

The symbol to be removed from the library.

 required

Raises:

Type Description
KeyError

If the symbol does not exist in the library.
Source code in SRToolkit/utils/symbol_library.py 
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def remove_symbol(self, symbol: str):
    """
    Removes a symbol from the library.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> len(library.symbols)
        1
        >>> library.remove_symbol("x")
        >>> len(library.symbols)
        0

    Args:
        symbol: The symbol to be removed from the library.

    Raises:
        KeyError: If the symbol does not exist in the library.
    """
    del self.symbols[symbol]

get_type(symbol)

Retrieves the type of a symbol from the library.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.get_type("x")
'var'

Parameters:

Name Type Description Default
symbol str

The symbol whose type is to be retrieved.

 required

Returns:

Type Description
str

The type of the symbol if it exists in the library, otherwise an empty string.
Source code in SRToolkit/utils/symbol_library.py 
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def get_type(self, symbol: str) -> str:
    """
    Retrieves the type of a symbol from the library.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.get_type("x")
        'var'

    Args:
        symbol: The symbol whose type is to be retrieved.

    Returns:
        The type of the symbol if it exists in the library, otherwise an empty string.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["type"]
    else:
        return ""

get_precedence(symbol)

Retrieves the precedence of the given symbol.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.get_precedence("x")
0

Parameters:

Name Type Description Default
symbol str

The symbol whose precedence is to be retrieved.

 required

Returns:

Type Description
int

The precedence of the symbol if it exists in the library, otherwise -1.
Source code in SRToolkit/utils/symbol_library.py 
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def get_precedence(self, symbol: str) -> int:
    """
    Retrieves the precedence of the given symbol.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.get_precedence("x")
        0

    Args:
        symbol: The symbol whose precedence is to be retrieved.

    Returns:
        The precedence of the symbol if it exists in the library, otherwise -1.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["precedence"]
    else:
        return -1

get_np_fn(symbol)

Returns the numpy function corresponding to the given symbol.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.get_np_fn("x")
'x'

Parameters:

Name Type Description Default
symbol str

The symbol to look up.

 required

Returns:

Type Description
str

The numpy function corresponding to the given symbol, or an empty string if the symbol was not found.
Source code in SRToolkit/utils/symbol_library.py 
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def get_np_fn(self, symbol: str) -> str:
    """
    Returns the numpy function corresponding to the given symbol.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.get_np_fn("x")
        'x'

    Args:
        symbol: The symbol to look up.

    Returns:
        The numpy function corresponding to the given symbol, or an empty string if the symbol was not found.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["np_fn"]
    else:
        return ""

default_symbols(num_variables=25) staticmethod

Creates a SymbolLibrary instance populated with default mathematical symbols.

This method adds a set of predefined symbols to a SymbolLibrary instance, representing common mathematical operations, functions, constants, and optional variables. The symbols include basic arithmetic operations, trigonometric and exponential functions, and mathematical constants like pi and e.

If num_variables is greater than 0, it adds variables labeled 'X_0' to 'X_{num_variables-1}', each associated with a column in a data array X.

Note: The variables in the default_symbols function are added in the predefined order, which is the same order as the columns in the data array X.

Examples:

>>> library = SymbolLibrary.default_symbols()
>>> len(library.symbols)
44

Parameters:

Name Type Description Default
num_variables int

The number of variables to add to the library (default is 25).

 25

Returns:

Type Description
SymbolLibrary

A SymbolLibrary instance populated with default mathematical symbols.
Source code in SRToolkit/utils/symbol_library.py 
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@staticmethod
def default_symbols(num_variables: int = 25) -> "SymbolLibrary":
    """
    Creates a SymbolLibrary instance populated with default mathematical symbols.

    This method adds a set of predefined symbols to a SymbolLibrary instance,
    representing common mathematical operations, functions, constants, and optional
    variables. The symbols include basic arithmetic operations, trigonometric and
    exponential functions, and mathematical constants like pi and e.

    If num_variables is greater than 0, it adds variables labeled 'X_0' to 'X_{num_variables-1}', each
     associated with a column in a data array X.

    Note: The variables in the default_symbols function are added in the predefined order,
    which is the same order as the columns in the data array X.

    Examples:
        >>> library = SymbolLibrary.default_symbols()
        >>> len(library.symbols)
        44

    Args:
        num_variables: The number of variables to add to the library (default is 25).

    Returns:
        A SymbolLibrary instance populated with default mathematical symbols.
    """
    sl = SymbolLibrary()
    sl.add_symbol("+", symbol_type="op", precedence=0, np_fn="{} = {} + {}")
    sl.add_symbol("-", symbol_type="op", precedence=0, np_fn="{} = {} - {}")
    sl.add_symbol("*", symbol_type="op", precedence=1, np_fn="{} = {} * {}")
    sl.add_symbol("/", symbol_type="op", precedence=1, np_fn="{} = {} / {}")
    sl.add_symbol("^", symbol_type="op", precedence=2, np_fn="{} = np.pow({},{})")
    sl.add_symbol("u-", symbol_type="fn", precedence=5, np_fn="{} = -{}")
    sl.add_symbol("sqrt", symbol_type="fn", precedence=5, np_fn="{} = np.sqrt({})")
    sl.add_symbol("sin", symbol_type="fn", precedence=5, np_fn="{} = np.sin({})")
    sl.add_symbol("cos", symbol_type="fn", precedence=5, np_fn="{} = np.cos({})")
    sl.add_symbol("exp", symbol_type="fn", precedence=5, np_fn="{} = np.exp({})")
    sl.add_symbol("ln", symbol_type="fn", precedence=5, np_fn="{} = np.log({})")
    sl.add_symbol("log", symbol_type="fn", precedence=5, np_fn="{} = np.log10({})")
    sl.add_symbol("^-1", symbol_type="fn", precedence=-1, np_fn="{} = 1/{}")
    sl.add_symbol("^2", symbol_type="fn", precedence=-1, np_fn="{} = {}**2")
    sl.add_symbol("^3", symbol_type="fn", precedence=-1, np_fn="{} = {}**3")
    sl.add_symbol("^4", symbol_type="fn", precedence=-1, np_fn="{} = {}**4")
    sl.add_symbol("^5", symbol_type="fn", precedence=-1, np_fn="{} = {}**5")
    sl.add_symbol("pi", symbol_type="lit", precedence=5, np_fn="np.pi")
    sl.add_symbol("e", symbol_type="lit", precedence=5, np_fn="np.e")
    sl.add_symbol("C", symbol_type="const", precedence=5, np_fn="C[{}]")

    if num_variables > 0:
        for i in range(num_variables):
            sl.add_symbol(f"X_{i}", "var", 5, "X[:, {}]".format(i))

    return sl