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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", "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()
        self.num_variables = 0

    def __len__(self) -> int:
        """
        Returns the number of symbols currently stored in the SymbolLibrary.

        Examples:
             >>> library = SymbolLibrary.default_symbols(5)
             >>> len(library)
             34
             >>> library.add_symbol("a", "lit", 5, "a", "a")
             >>> len(library)
             35

        Returns
            Number of symbols currently stored in the SymbolLibrary.
        """
        return len(self.symbols)

    def __str__(self) -> str:
        r"""
        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", "x")
            >>> str(library)
            'x'
            >>> library.add_symbol("sin", "fn", 5, "{} = np.sin({})", r"\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":
        r"""
        Creates a copy of the SymbolLibrary instance.

        Examples:
            >>> old_symbols = SymbolLibrary()
            >>> old_symbols.add_symbol("x", "var", 0, "x", "x")
            >>> print(old_symbols)
            x
            >>> new_symbols = copy.copy(old_symbols)
            >>> new_symbols.add_symbol("sin", "fn", 5, "{} = np.sin({})", r"\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, latex_str: str = None):
        r"""
        Adds a symbol to the library. A symbol should have a type, precedence, a numpy function, and a LaTeX template 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.

        We recommend you use a single token of "const" type as using multiple might lead to more work, errors, and less
        readability.

        If the argument 'latex_str' is ommited, a default LaTeX template will be generated for the symbol. In case of symbol 'symb', the default template
        will be '{} \text{symb} {}' for an operator,'\text{symb} {}' for a function, and '\text{symb}' otherwise.

        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({})", r"\sin {}")
            >>> library.add_symbol("C", "const", 5, "C[{}]", r"c_{}")
            >>> library.add_symbol("X_0", "var", 5, "X[:, 0]", r"X_0")
            >>> library.add_symbol("pi", "lit", 5, "np.pi", r"\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.
            latex_str: A string that represents how the symbol is written in LaTeX
        """
        if latex_str is None:
            if symbol_type == "var":
                latex_str = f"{{}} \text{{{symbol}}} {{}}"
            elif symbol_type == "fn":
                latex_str = f"\text{{{symbol}}} {{}}"
            else:
                latex_str = f"\text{{{symbol}}}"

        if symbol_type == "var" and (np_fn is None or np_fn == ""):
            np_fn = "X[:, {}]".format(self.num_variables)

        if symbol_type == "var":
            self.num_variables += 1

        self.symbols[symbol] = {
            "symbol": symbol,
            "type": symbol_type,
            "precedence": precedence,
            "np_fn": np_fn,
            "latex_str": latex_str
        }

    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 ""

    def get_latex_str(self, symbol):
        """
        Returns the LaTeX template for the corresponding symbol.

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

        Args:
            symbol: The symbol to look up.

        Returns:
            The LaTeX template for the corresponding symbol, or an empty string if the symbol was not found.
        """
        if symbol in self.symbols:
            return self.symbols[symbol]["latex_str"]
        else:
            return ""

    def get_symbols_of_type(self, symbol_type: str) -> List[str]:
        """
        Returns a list of symbols with the requested type ("op", "fn", "var", "const", "lit").

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.add_symbol("y", "var", 0, "y")
            >>> library.get_symbols_of_type("var")
            ['x', 'y']

        Args:
            symbol_type: Type of symbols you want to get.

        Returns:
            A list of symbols with the requested type
        """
        symbols = list()
        for symbol in self.symbols.keys():
            if self.get_type(symbol) == symbol_type:
                symbols.append(symbol)

        return symbols

    def symbols2index(self) -> Dict[str, int]:
        """
        Generates a dictionary mapping symbols to their indices in the symbol list.

        Examples:
            >>> library = SymbolLibrary()
            >>> library.add_symbol("x", "var", 0, "x")
            >>> library.add_symbol("y", "var", 0, "y")
            >>> print(library.symbols2index())
            {'x': 0, 'y': 1}
            >>> library.remove_symbol("x")
            >>> print(library.symbols2index())
            {'y': 0}

        Returns:
            A dictionary mapping symbols to their indices in the symbol list.
        """
        return {s:i for i, s in enumerate(self.symbols.keys())}

    @staticmethod
    def from_symbol_list(symbols: List[str], num_variables=25):
        """
        Creates an instance of SymbolLibrary from a list of symbols and number of variables. The list of currently
        supported symbols (by default) can be seen in the SymbolLibrary.default_symbols() function.

        Examples:
            >>> library = SymbolLibrary().from_symbol_list(["+", "*", "C"], num_variables=2)
            >>> len(library.symbols)
            5

        Args:
            symbols: List of symbols you want.
            num_variables: Number of variables you want.

        Returns:
            An instance of SymbolLibrary
        """
        variables = [f"X_{i}" for i in range(num_variables)]
        symbols = symbols + variables

        sl = SymbolLibrary.default_symbols(num_variables)

        all_symbols = list(sl.symbols.keys())
        for symbol in all_symbols:
            if symbol not in symbols:
                sl.remove_symbol(symbol)

        return sl

    @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.

        By default, we currently support the following symbols: "+", "-", "*", "/", "^", "u-" (unary minus), "sqrt",
        "sin", "cos", "exp", "tan", "arcsin", "arccos", "arctan", "sinh", "cosh", "tanh", "floor", "ceil", "ln", "log",
        "^-1", "^2", "^3", "^4", "^5", "pi", "e", "C" (unknown constant).

        Notes: 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)
            54

        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="{} = {} + {}", latex_str=r"{} + {}")
        sl.add_symbol("-", symbol_type="op", precedence=0, np_fn="{} = {} - {}", latex_str=r"{} - {}")
        sl.add_symbol("*", symbol_type="op", precedence=1, np_fn="{} = {} * {}", latex_str=r"{} \cdot {}")
        sl.add_symbol("/", symbol_type="op", precedence=1, np_fn="{} = {} / {}", latex_str=r"\frac{{{}}}{{{}}}")
        sl.add_symbol("^", symbol_type="op", precedence=2, np_fn="{} = np.power({},{})", latex_str=r"{}^{{{}}}")
        sl.add_symbol("u-", symbol_type="fn", precedence=5, np_fn="{} = -{}", latex_str=r"- {}")
        sl.add_symbol("sqrt", symbol_type="fn", precedence=5, np_fn="{} = np.sqrt({})", latex_str=r"\sqrt {{{}}}")
        sl.add_symbol("sin", symbol_type="fn", precedence=5, np_fn="{} = np.sin({})", latex_str=r"\sin {}")
        sl.add_symbol("cos", symbol_type="fn", precedence=5, np_fn="{} = np.cos({})", latex_str=r"\cos {}")
        sl.add_symbol("exp", symbol_type="fn", precedence=5, np_fn="{} = np.exp({})", latex_str=r"e^{{{}}}")
        sl.add_symbol("tan", symbol_type="fn", precedence=5, np_fn="{} = np.tan({})", latex_str=r"\tan {}")
        sl.add_symbol("arcsin", symbol_type="fn", precedence=5, np_fn="{} = np.arcsin({})", latex_str=r"\arcsin {}")
        sl.add_symbol("arccos", symbol_type="fn", precedence=5, np_fn="{} = np.arccos({})", latex_str=r"\arccos {}")
        sl.add_symbol("arctan", symbol_type="fn", precedence=5, np_fn="{} = np.arctan({})", latex_str=r"\arctan {}")
        sl.add_symbol("sinh", symbol_type="fn", precedence=5, np_fn="{} = np.sinh({})", latex_str=r"\sinh {}")
        sl.add_symbol("cosh", symbol_type="fn", precedence=5, np_fn="{} = np.cosh({})", latex_str=r"\cosh {}")
        sl.add_symbol("tanh", symbol_type="fn", precedence=5, np_fn="{} = np.tanh({})", latex_str=r"\tanh {}")
        sl.add_symbol("floor", symbol_type="fn", precedence=5, np_fn="{} = np.floor({})", latex_str=r"\lfloor {} \rfloor")
        sl.add_symbol("ceil", symbol_type="fn", precedence=5, np_fn="{} = np.ceil({})", latex_str=r"\lceil {} \rceil")
        sl.add_symbol("ln", symbol_type="fn", precedence=5, np_fn="{} = np.log({})", latex_str=r"\ln {}")
        sl.add_symbol("log", symbol_type="fn", precedence=5, np_fn="{} = np.log10({})", latex_str=r"\log_{{10}} {}")
        sl.add_symbol("^-1", symbol_type="fn", precedence=-1, np_fn="{} = 1/{}", latex_str=r"{}^{{-1}}")
        sl.add_symbol("^2", symbol_type="fn", precedence=-1, np_fn="{} = {}**2", latex_str=r"{}^2")
        sl.add_symbol("^3", symbol_type="fn", precedence=-1, np_fn="{} = {}**3", latex_str=r"{}^3")
        sl.add_symbol("^4", symbol_type="fn", precedence=-1, np_fn="{} = {}**4", latex_str=r"{}^4")
        sl.add_symbol("^5", symbol_type="fn", precedence=-1, np_fn="{} = {}**5", latex_str=r"{}^5")
        sl.add_symbol("pi", symbol_type="lit", precedence=5, np_fn="np.full(X.shape[0], np.pi)", latex_str=r"\pi")
        sl.add_symbol("e", symbol_type="lit", precedence=5, np_fn="np.full(X.shape[0], np.e)", latex_str=r"e")
        sl.add_symbol("C", symbol_type="const", precedence=5, np_fn="np.full(X.shape[0], C[{}])", latex_str=r"C_{{{}}}")

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

__len__()

Returns the number of symbols currently stored in the SymbolLibrary.

Examples:

>>> library = SymbolLibrary.default_symbols(5)
>>> len(library)
34
>>> library.add_symbol("a", "lit", 5, "a", "a")
>>> len(library)
35

Returns Number of symbols currently stored in the SymbolLibrary.

Source code in SRToolkit/utils/symbol_library.py 
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def __len__(self) -> int:
    """
    Returns the number of symbols currently stored in the SymbolLibrary.

    Examples:
         >>> library = SymbolLibrary.default_symbols(5)
         >>> len(library)
         34
         >>> library.add_symbol("a", "lit", 5, "a", "a")
         >>> len(library)
         35

    Returns
        Number of symbols currently stored in the SymbolLibrary.
    """
    return len(self.symbols)

__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", "x")
>>> str(library)
'x'
>>> library.add_symbol("sin", "fn", 5, "{} = np.sin({})", r"\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:
    r"""
    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", "x")
        >>> str(library)
        'x'
        >>> library.add_symbol("sin", "fn", 5, "{} = np.sin({})", r"\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", "x")
>>> print(old_symbols)
x
>>> new_symbols = copy.copy(old_symbols)
>>> new_symbols.add_symbol("sin", "fn", 5, "{} = np.sin({})", r"\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":
    r"""
    Creates a copy of the SymbolLibrary instance.

    Examples:
        >>> old_symbols = SymbolLibrary()
        >>> old_symbols.add_symbol("x", "var", 0, "x", "x")
        >>> print(old_symbols)
        x
        >>> new_symbols = copy.copy(old_symbols)
        >>> new_symbols.add_symbol("sin", "fn", 5, "{} = np.sin({})", r"\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, latex_str=None)

Adds a symbol to the library. A symbol should have a type, precedence, a numpy function, and a LaTeX template 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.

We recommend you use a single token of "const" type as using multiple might lead to more work, errors, and less readability.

If the argument 'latex_str' is ommited, a default LaTeX template will be generated for the symbol. In case of symbol 'symb', the default template will be '{} \text{symb} {}' for an operator,'\text{symb} {}' for a function, and '\text{symb}' otherwise.

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({})", r"\sin {}")
>>> library.add_symbol("C", "const", 5, "C[{}]", r"c_{}")
>>> library.add_symbol("X_0", "var", 5, "X[:, 0]", r"X_0")
>>> library.add_symbol("pi", "lit", 5, "np.pi", r"\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
latex_str str

A string that represents how the symbol is written in LaTeX

 None
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, latex_str: str = None):
    r"""
    Adds a symbol to the library. A symbol should have a type, precedence, a numpy function, and a LaTeX template 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.

    We recommend you use a single token of "const" type as using multiple might lead to more work, errors, and less
    readability.

    If the argument 'latex_str' is ommited, a default LaTeX template will be generated for the symbol. In case of symbol 'symb', the default template
    will be '{} \text{symb} {}' for an operator,'\text{symb} {}' for a function, and '\text{symb}' otherwise.

    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({})", r"\sin {}")
        >>> library.add_symbol("C", "const", 5, "C[{}]", r"c_{}")
        >>> library.add_symbol("X_0", "var", 5, "X[:, 0]", r"X_0")
        >>> library.add_symbol("pi", "lit", 5, "np.pi", r"\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.
        latex_str: A string that represents how the symbol is written in LaTeX
    """
    if latex_str is None:
        if symbol_type == "var":
            latex_str = f"{{}} \text{{{symbol}}} {{}}"
        elif symbol_type == "fn":
            latex_str = f"\text{{{symbol}}} {{}}"
        else:
            latex_str = f"\text{{{symbol}}}"

    if symbol_type == "var" and (np_fn is None or np_fn == ""):
        np_fn = "X[:, {}]".format(self.num_variables)

    if symbol_type == "var":
        self.num_variables += 1

    self.symbols[symbol] = {
        "symbol": symbol,
        "type": symbol_type,
        "precedence": precedence,
        "np_fn": np_fn,
        "latex_str": latex_str
    }

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 ""

get_latex_str(symbol)

Returns the LaTeX template for the corresponding symbol.

Examples:

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

Parameters:

Name Type Description Default
symbol

The symbol to look up.

 required

Returns:

Type Description

The LaTeX template for the corresponding 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_latex_str(self, symbol):
    """
    Returns the LaTeX template for the corresponding symbol.

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

    Args:
        symbol: The symbol to look up.

    Returns:
        The LaTeX template for the corresponding symbol, or an empty string if the symbol was not found.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["latex_str"]
    else:
        return ""

get_symbols_of_type(symbol_type)

Returns a list of symbols with the requested type ("op", "fn", "var", "const", "lit").

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.add_symbol("y", "var", 0, "y")
>>> library.get_symbols_of_type("var")
['x', 'y']

Parameters:

Name Type Description Default
symbol_type str

Type of symbols you want to get.

 required

Returns:

Type Description
List[str]

A list of symbols with the requested type
Source code in SRToolkit/utils/symbol_library.py 
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def get_symbols_of_type(self, symbol_type: str) -> List[str]:
    """
    Returns a list of symbols with the requested type ("op", "fn", "var", "const", "lit").

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.add_symbol("y", "var", 0, "y")
        >>> library.get_symbols_of_type("var")
        ['x', 'y']

    Args:
        symbol_type: Type of symbols you want to get.

    Returns:
        A list of symbols with the requested type
    """
    symbols = list()
    for symbol in self.symbols.keys():
        if self.get_type(symbol) == symbol_type:
            symbols.append(symbol)

    return symbols

symbols2index()

Generates a dictionary mapping symbols to their indices in the symbol list.

Examples:

>>> library = SymbolLibrary()
>>> library.add_symbol("x", "var", 0, "x")
>>> library.add_symbol("y", "var", 0, "y")
>>> print(library.symbols2index())
{'x': 0, 'y': 1}
>>> library.remove_symbol("x")
>>> print(library.symbols2index())
{'y': 0}

Returns:

Type Description
Dict[str, int]

A dictionary mapping symbols to their indices in the symbol list.
Source code in SRToolkit/utils/symbol_library.py 
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def symbols2index(self) -> Dict[str, int]:
    """
    Generates a dictionary mapping symbols to their indices in the symbol list.

    Examples:
        >>> library = SymbolLibrary()
        >>> library.add_symbol("x", "var", 0, "x")
        >>> library.add_symbol("y", "var", 0, "y")
        >>> print(library.symbols2index())
        {'x': 0, 'y': 1}
        >>> library.remove_symbol("x")
        >>> print(library.symbols2index())
        {'y': 0}

    Returns:
        A dictionary mapping symbols to their indices in the symbol list.
    """
    return {s:i for i, s in enumerate(self.symbols.keys())}

from_symbol_list(symbols, num_variables=25) staticmethod

Creates an instance of SymbolLibrary from a list of symbols and number of variables. The list of currently supported symbols (by default) can be seen in the SymbolLibrary.default_symbols() function.

Examples:

>>> library = SymbolLibrary().from_symbol_list(["+", "*", "C"], num_variables=2)
>>> len(library.symbols)
5

Parameters:

Name Type Description Default
symbols List[str]

List of symbols you want.

 required
num_variables

Number of variables you want.

 25

Returns:

Type Description

An instance of SymbolLibrary
Source code in SRToolkit/utils/symbol_library.py 
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@staticmethod
def from_symbol_list(symbols: List[str], num_variables=25):
    """
    Creates an instance of SymbolLibrary from a list of symbols and number of variables. The list of currently
    supported symbols (by default) can be seen in the SymbolLibrary.default_symbols() function.

    Examples:
        >>> library = SymbolLibrary().from_symbol_list(["+", "*", "C"], num_variables=2)
        >>> len(library.symbols)
        5

    Args:
        symbols: List of symbols you want.
        num_variables: Number of variables you want.

    Returns:
        An instance of SymbolLibrary
    """
    variables = [f"X_{i}" for i in range(num_variables)]
    symbols = symbols + variables

    sl = SymbolLibrary.default_symbols(num_variables)

    all_symbols = list(sl.symbols.keys())
    for symbol in all_symbols:
        if symbol not in symbols:
            sl.remove_symbol(symbol)

    return sl

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.

By default, we currently support the following symbols: "+", "-", "*", "/", "^", "u-" (unary minus), "sqrt", "sin", "cos", "exp", "tan", "arcsin", "arccos", "arctan", "sinh", "cosh", "tanh", "floor", "ceil", "ln", "log", "^-1", "^2", "^3", "^4", "^5", "pi", "e", "C" (unknown constant).

Notes: 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)
54

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.

    By default, we currently support the following symbols: "+", "-", "*", "/", "^", "u-" (unary minus), "sqrt",
    "sin", "cos", "exp", "tan", "arcsin", "arccos", "arctan", "sinh", "cosh", "tanh", "floor", "ceil", "ln", "log",
    "^-1", "^2", "^3", "^4", "^5", "pi", "e", "C" (unknown constant).

    Notes: 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)
        54

    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="{} = {} + {}", latex_str=r"{} + {}")
    sl.add_symbol("-", symbol_type="op", precedence=0, np_fn="{} = {} - {}", latex_str=r"{} - {}")
    sl.add_symbol("*", symbol_type="op", precedence=1, np_fn="{} = {} * {}", latex_str=r"{} \cdot {}")
    sl.add_symbol("/", symbol_type="op", precedence=1, np_fn="{} = {} / {}", latex_str=r"\frac{{{}}}{{{}}}")
    sl.add_symbol("^", symbol_type="op", precedence=2, np_fn="{} = np.power({},{})", latex_str=r"{}^{{{}}}")
    sl.add_symbol("u-", symbol_type="fn", precedence=5, np_fn="{} = -{}", latex_str=r"- {}")
    sl.add_symbol("sqrt", symbol_type="fn", precedence=5, np_fn="{} = np.sqrt({})", latex_str=r"\sqrt {{{}}}")
    sl.add_symbol("sin", symbol_type="fn", precedence=5, np_fn="{} = np.sin({})", latex_str=r"\sin {}")
    sl.add_symbol("cos", symbol_type="fn", precedence=5, np_fn="{} = np.cos({})", latex_str=r"\cos {}")
    sl.add_symbol("exp", symbol_type="fn", precedence=5, np_fn="{} = np.exp({})", latex_str=r"e^{{{}}}")
    sl.add_symbol("tan", symbol_type="fn", precedence=5, np_fn="{} = np.tan({})", latex_str=r"\tan {}")
    sl.add_symbol("arcsin", symbol_type="fn", precedence=5, np_fn="{} = np.arcsin({})", latex_str=r"\arcsin {}")
    sl.add_symbol("arccos", symbol_type="fn", precedence=5, np_fn="{} = np.arccos({})", latex_str=r"\arccos {}")
    sl.add_symbol("arctan", symbol_type="fn", precedence=5, np_fn="{} = np.arctan({})", latex_str=r"\arctan {}")
    sl.add_symbol("sinh", symbol_type="fn", precedence=5, np_fn="{} = np.sinh({})", latex_str=r"\sinh {}")
    sl.add_symbol("cosh", symbol_type="fn", precedence=5, np_fn="{} = np.cosh({})", latex_str=r"\cosh {}")
    sl.add_symbol("tanh", symbol_type="fn", precedence=5, np_fn="{} = np.tanh({})", latex_str=r"\tanh {}")
    sl.add_symbol("floor", symbol_type="fn", precedence=5, np_fn="{} = np.floor({})", latex_str=r"\lfloor {} \rfloor")
    sl.add_symbol("ceil", symbol_type="fn", precedence=5, np_fn="{} = np.ceil({})", latex_str=r"\lceil {} \rceil")
    sl.add_symbol("ln", symbol_type="fn", precedence=5, np_fn="{} = np.log({})", latex_str=r"\ln {}")
    sl.add_symbol("log", symbol_type="fn", precedence=5, np_fn="{} = np.log10({})", latex_str=r"\log_{{10}} {}")
    sl.add_symbol("^-1", symbol_type="fn", precedence=-1, np_fn="{} = 1/{}", latex_str=r"{}^{{-1}}")
    sl.add_symbol("^2", symbol_type="fn", precedence=-1, np_fn="{} = {}**2", latex_str=r"{}^2")
    sl.add_symbol("^3", symbol_type="fn", precedence=-1, np_fn="{} = {}**3", latex_str=r"{}^3")
    sl.add_symbol("^4", symbol_type="fn", precedence=-1, np_fn="{} = {}**4", latex_str=r"{}^4")
    sl.add_symbol("^5", symbol_type="fn", precedence=-1, np_fn="{} = {}**5", latex_str=r"{}^5")
    sl.add_symbol("pi", symbol_type="lit", precedence=5, np_fn="np.full(X.shape[0], np.pi)", latex_str=r"\pi")
    sl.add_symbol("e", symbol_type="lit", precedence=5, np_fn="np.full(X.shape[0], np.e)", latex_str=r"e")
    sl.add_symbol("C", symbol_type="const", precedence=5, np_fn="np.full(X.shape[0], C[{}])", latex_str=r"C_{{{}}}")

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

    return sl