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Symbol Library

SRToolkit.utils.symbol_library

The SymbolLibrary class for managing the token vocabulary used in symbolic regression expressions.

SymbolLibrary 

SymbolLibrary(symbols: Optional[List[str]] = None, num_variables: int = 0, preamble: Optional[List[str]] = None)

A registry of tokens and their properties, used throughout the toolkit to parse, compile, and generate symbolic expressions.

By default, the library uses NumPy for operator and function evaluation. To use a different backend, pass the required import statements via preamble.

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()
>>> # You can also initialize the library with a list of symbols (listed in SymbolLibrary.default_symbols)
>>> # and the number of variables.
>>> library2 = SymbolLibrary(["+", "*", "sin"], num_variables=2)
>>> len(library2)
5

Parameters:

Name Type Description Default
symbols Optional[List[str]]

Symbols to pre-populate from the default set. None produces an empty library. See default_symbols for the supported names.

 None
num_variables int

Number of variable tokens to add, labeled X_0 through X_{num_variables-1}. Default is 0.

 0
preamble Optional[List[str]]

Import statements prepended to compiled expression functions. Defaults to ["import numpy as np"].

 None

Attributes:

Name Type Description
symbols

Mapping from token string to its property dict (type, precedence, NumPy function string, LaTeX template).
Source code in SRToolkit/utils/symbol_library.py 
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def __init__(
    self, symbols: Optional[List[str]] = None, num_variables: int = 0, preamble: Optional[List[str]] = None
) -> None:
    """
    A registry of tokens and their properties, used throughout the toolkit to parse,
    compile, and generate symbolic expressions.

    By default, the library uses NumPy for operator and function evaluation. To use a
    different backend, pass the required import statements via ``preamble``.

    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()
        >>> # You can also initialize the library with a list of symbols (listed in SymbolLibrary.default_symbols)
        >>> # and the number of variables.
        >>> library2 = SymbolLibrary(["+", "*", "sin"], num_variables=2)
        >>> len(library2)
        5

    Args:
        symbols: Symbols to pre-populate from the default set. ``None`` produces an empty
            library. See [default_symbols][SRToolkit.utils.symbol_library.SymbolLibrary.default_symbols] for the supported names.
        num_variables: Number of variable tokens to add, labeled ``X_0`` through
            ``X_{num_variables-1}``. Default is ``0``.
        preamble: Import statements prepended to compiled expression functions.
            Defaults to ``["import numpy as np"]``.

    Attributes:
        symbols: Mapping from token string to its property dict (type, precedence,
            NumPy function string, LaTeX template).
    """
    if preamble is None:
        self.preamble = ["import numpy as np"]
    else:
        self.preamble = preamble

    if symbols is None and num_variables == 0:
        self.symbols: Dict[str, Any] = dict()
        self.num_variables = 0
    else:
        if symbols is None:
            symbols = []

        self.symbols = SymbolLibrary.from_symbol_list(symbols, num_variables).symbols
        self.num_variables = num_variables

add_symbol 

add_symbol(symbol: str, symbol_type: str, precedence: int, np_fn: str, latex_str: Optional[str] = None)

Add a token to the library with its associated type, precedence, NumPy function string, and LaTeX template.

Symbol types:

  • "op": binary operator (e.g. +, *).
  • "fn": unary function (e.g. sin, sqrt).
  • "lit": literal with a fixed value (e.g. pi, e).
  • "const": free constant whose value is optimised during parameter estimation (e.g. C). Using a single "const" token is recommended; multiple tokens increase complexity and reduce readability.
  • "var": input variable whose values are read from the data array X.

If latex_str is omitted, a default template is generated: "{} \text{symb} {}" for operators, "\text{symb} {}" for functions, and "\text{symb}" otherwise.

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

Token string to register.

 required
symbol_type str

One of "op", "fn", "lit", "const", or "var".

 required
precedence int

Operator precedence, used for infix reconstruction and PCFG generation.

 required
np_fn str

Python/NumPy expression string used in compiled callables (e.g. "{} = np.sin({})") .

 required
latex_str Optional[str]

LaTeX template string with {} placeholders for operands. Auto-generated if omitted.

 None

Raises:

Type Description
ValueError

If symbol_type is not one of the valid types.
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: Optional[str] = None,
):
    r"""
    Add a token to the library with its associated type, precedence, NumPy function
    string, and LaTeX template.

    Symbol types:

    - ``"op"``: binary operator (e.g. ``+``, ``*``).
    - ``"fn"``: unary function (e.g. ``sin``, ``sqrt``).
    - ``"lit"``: literal with a fixed value (e.g. ``pi``, ``e``).
    - ``"const"``: free constant whose value is optimised during parameter estimation
      (e.g. ``C``). Using a single ``"const"`` token is recommended; multiple tokens
      increase complexity and reduce readability.
    - ``"var"``: input variable whose values are read from the data array ``X``.

    If ``latex_str`` is omitted, a default template is generated: ``"{} \text{symb} {}"``
    for operators, ``"\text{symb} {}"`` for functions, and ``"\text{symb}"`` otherwise.

    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: Token string to register.
        symbol_type: One of ``"op"``, ``"fn"``, ``"lit"``, ``"const"``, or ``"var"``.
        precedence: Operator precedence, used for infix reconstruction and PCFG generation.
        np_fn: Python/NumPy expression string used in compiled callables
            (e.g. ``"{} = np.sin({})"``) .
        latex_str: LaTeX template string with ``{}`` placeholders for operands.
            Auto-generated if omitted.

    Raises:
        ValueError: If ``symbol_type`` is not one of the valid types.
    """
    if symbol_type not in VALID_SYMBOL_TYPES:
        raise ValueError(f"Invalid symbol type '{symbol_type}'. Must be one of: {sorted(VALID_SYMBOL_TYPES)}")

    if latex_str is None:
        if symbol_type == "op":
            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 

remove_symbol(symbol: str)

Remove a token 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

Token string to remove.

 required

Raises:

Type Description
KeyError

If symbol is not present in the library.
Source code in SRToolkit/utils/symbol_library.py 
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def remove_symbol(self, symbol: str):
    """
    Remove a token 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: Token string to remove.

    Raises:
        KeyError: If ``symbol`` is not present in the library.
    """
    del self.symbols[symbol]

get_type 

get_type(symbol: str) -> str

Return the type of a symbol.

Examples:

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

Parameters:

Name Type Description Default
symbol str

Token to look up.

 required

Returns:

Type Description
str

The type string ("op", "fn", "lit", "const", or "var") if the symbol is 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:
    """
    Return the type of a symbol.

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

    Args:
        symbol: Token to look up.

    Returns:
        The type string (``"op"``, ``"fn"``, ``"lit"``, ``"const"``, or ``"var"``) if the symbol is in the library, otherwise an empty string.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["type"]
    else:
        return ""

get_precedence 

get_precedence(symbol: str) -> int

Return the precedence of a symbol.

Examples:

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

Parameters:

Name Type Description Default
symbol str

Token to look up.

 required

Returns:

Type Description
int

The precedence value if the symbol is in the library, otherwise -1.
Source code in SRToolkit/utils/symbol_library.py 
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def get_precedence(self, symbol: str) -> int:
    """
    Return the precedence of a symbol.

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

    Args:
        symbol: Token to look up.

    Returns:
        The precedence value if the symbol is in the library, otherwise ``-1``.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["precedence"]
    else:
        return -1

get_np_fn 

get_np_fn(symbol: str) -> str

Return the NumPy function string for a symbol.

Examples:

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

Parameters:

Name Type Description Default
symbol str

Token to look up.

 required

Returns:

Type Description
str

The NumPy function string if the symbol is in the library, otherwise an empty string.
Source code in SRToolkit/utils/symbol_library.py 
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def get_np_fn(self, symbol: str) -> str:
    """
    Return the NumPy function string for a symbol.

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

    Args:
        symbol: Token to look up.

    Returns:
        The NumPy function string if the symbol is in the library, otherwise an empty string.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["np_fn"]
    else:
        return ""

get_latex_str 

get_latex_str(symbol: str) -> str

Return the LaTeX template string for a symbol.

Examples:

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

Parameters:

Name Type Description Default
symbol str

Token to look up.

 required

Returns:

Type Description
str

The LaTeX template string if the symbol is in the library, otherwise an empty string.
Source code in SRToolkit/utils/symbol_library.py 
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def get_latex_str(self, symbol: str) -> str:
    """
    Return the LaTeX template string for a symbol.

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

    Args:
        symbol: Token to look up.

    Returns:
        The LaTeX template string if the symbol is in the library, otherwise an empty string.
    """
    if symbol in self.symbols:
        return self.symbols[symbol]["latex_str"]
    else:
        return ""

get_symbols_of_type 

get_symbols_of_type(symbol_type: str) -> List[str]

Return all symbols of a given type.

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 to filter by. One of "op", "fn", "var", "const", "lit".

 required

Returns:

Type Description
List[str]

List of token strings matching 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]:
    """
    Return all symbols of a given type.

    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 to filter by. One of ``"op"``, ``"fn"``, ``"var"``,
            ``"const"``, ``"lit"``.

    Returns:
        List of token strings matching the requested type.
    """
    symbols = list()
    for symbol in self.symbols.keys():
        if self.get_type(symbol) == symbol_type:
            symbols.append(symbol)

    return symbols

symbols2index 

symbols2index() -> Dict[str, int]

Return a mapping from each token to its index in insertion order.

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]

Dict mapping each token string to its zero-based position in the library.
Source code in SRToolkit/utils/symbol_library.py 
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def symbols2index(self) -> Dict[str, int]:
    """
    Return a mapping from each token to its index in insertion order.

    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:
        Dict mapping each token string to its zero-based position in the library.
    """
    return {s: i for i, s in enumerate(self.symbols.keys())}

from_symbol_list staticmethod 

from_symbol_list(symbols: List[str], num_variables: int = 25) -> SymbolLibrary

Create a SymbolLibrary containing only the specified subset of default symbols.

The supported token names are those defined in default_symbols.

Examples:

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

Parameters:

Name Type Description Default
symbols List[str]

Token strings to include. Must be a subset of the default symbol names.

 required
num_variables int

Number of variable tokens (X_0 through X_{num_variables-1}). Default is 25.

 25

Returns:

Type Description
SymbolLibrary

A SymbolLibrary restricted to the requested symbols and variables.
Source code in SRToolkit/utils/symbol_library.py 
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@staticmethod
def from_symbol_list(symbols: List[str], num_variables: int = 25) -> "SymbolLibrary":
    """
    Create a [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary] containing only the specified subset of default symbols.

    The supported token names are those defined in [default_symbols][SRToolkit.utils.symbol_library.SymbolLibrary.default_symbols].

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

    Args:
        symbols: Token strings to include. Must be a subset of the default symbol names.
        num_variables: Number of variable tokens (``X_0`` through ``X_{num_variables-1}``).
            Default is ``25``.

    Returns:
        A [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary] restricted to the requested symbols and variables.
    """
    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 staticmethod 

default_symbols(num_variables: int = 25) -> SymbolLibrary

Return a SymbolLibrary pre-populated with standard mathematical symbols.

Supported tokens:

  • Operators ("op"): +, -, *, /, ^
  • Functions ("fn"): u-, sqrt, sin, cos, exp, tan, arcsin, arccos, arctan, sinh, cosh, tanh, floor, ceil, ln, log, ^-1, ^2, ^3, ^4, ^5
  • Literals ("lit"): pi, e
  • Free constant ("const"): C
  • Variables ("var"): X_0 through X_{num_variables-1}, mapped to columns of the input array in order.

Examples:

>>> library = SymbolLibrary.default_symbols()
>>> len(library.symbols)
54

Parameters:

Name Type Description Default
num_variables int

Number of variable tokens to include. Default is 25.

 25

Returns:

Type Description
SymbolLibrary

A SymbolLibrary populated with the symbols listed above.
Source code in SRToolkit/utils/symbol_library.py 
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@staticmethod
def default_symbols(num_variables: int = 25) -> "SymbolLibrary":
    """
    Return a [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary] pre-populated with standard mathematical symbols.

    Supported tokens:

    - **Operators** (``"op"``): ``+``, ``-``, ``*``, ``/``, ``^``
    - **Functions** (``"fn"``): ``u-``, ``sqrt``, ``sin``, ``cos``, ``exp``, ``tan``,
      ``arcsin``, ``arccos``, ``arctan``, ``sinh``, ``cosh``, ``tanh``, ``floor``,
      ``ceil``, ``ln``, ``log``, ``^-1``, ``^2``, ``^3``, ``^4``, ``^5``
    - **Literals** (``"lit"``): ``pi``, ``e``
    - **Free constant** (``"const"``): ``C``
    - **Variables** (``"var"``): ``X_0`` through ``X_{num_variables-1}``,
      mapped to columns of the input array in order.

    Examples:
        >>> library = SymbolLibrary.default_symbols()
        >>> len(library.symbols)
        54

    Args:
        num_variables: Number of variable tokens to include. Default is ``25``.

    Returns:
        A [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary] populated with the symbols listed above.
    """
    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

to_dict 

to_dict() -> dict

Serialize the library to a JSON-safe dictionary.

Returns:

Type Description
dict

A dictionary suitable for passing to from_dict.
Source code in SRToolkit/utils/symbol_library.py 
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def to_dict(self) -> dict:
    """
    Serialize the library to a JSON-safe dictionary.

    Returns:
        A dictionary suitable for passing to [from_dict][SRToolkit.utils.symbol_library.SymbolLibrary.from_dict].
    """
    return {
        "format_version": 1,
        "type": "SymbolLibrary",
        "symbols": self.symbols,
        "preamble": self.preamble,
        "num_variables": self.num_variables,
    }

from_dict staticmethod 

from_dict(d: dict) -> SymbolLibrary

Reconstruct a SymbolLibrary from a dictionary produced by to_dict.

Parameters:

Name Type Description Default
d dict

Dictionary representation of the library.

 required

Returns:

Type Description
SymbolLibrary

The reconstructed SymbolLibrary.

Raises:

Type Description
ValueError

If d["format_version"] is not 1.
Source code in SRToolkit/utils/symbol_library.py 
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@staticmethod
def from_dict(d: dict) -> "SymbolLibrary":
    """
    Reconstruct a [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary] from a dictionary produced by [to_dict][SRToolkit.utils.symbol_library.SymbolLibrary.to_dict].

    Args:
        d: Dictionary representation of the library.

    Returns:
        The reconstructed [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary].

    Raises:
        ValueError: If ``d["format_version"]`` is not ``1``.
    """
    if d.get("format_version", 1) != 1:
        raise ValueError(
            f"[SymbolLibrary.from_dict] Unsupported format_version: {d.get('format_version')!r}. Expected 1."
        )
    sl = SymbolLibrary()
    sl.symbols = d["symbols"]
    sl.preamble = d["preamble"]
    sl.num_variables = d["num_variables"]
    return sl

__len__ 

__len__() -> int

Return the number of symbols currently in the library.

Examples:

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

Returns:

Type Description
int

Number of tokens registered in the library.
Source code in SRToolkit/utils/symbol_library.py 
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def __len__(self) -> int:
    """
    Return the number of symbols currently in the library.

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

    Returns:
        Number of tokens registered in the library.
    """
    return len(self.symbols)

__str__ 

__str__() -> str

Return a comma-separated string of all registered token strings.

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

All token names joined by ", ", in insertion order.
Source code in SRToolkit/utils/symbol_library.py 
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def __str__(self) -> str:
    r"""
    Return a comma-separated string of all registered token strings.

    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:
        All token names joined by ``", "``, in insertion order.
    """
    return ", ".join(self.symbols.keys())

__copy__ 

__copy__() -> SymbolLibrary

Return a copy of the library with independent copies of all attributes.

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 new SymbolLibrary instance with deep-copied symbols and preamble.
Source code in SRToolkit/utils/symbol_library.py 
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def __copy__(self) -> "SymbolLibrary":
    r"""
    Return a copy of the library with independent copies of all attributes.

    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 new [SymbolLibrary][SRToolkit.utils.symbol_library.SymbolLibrary] instance with deep-copied symbols and preamble.
    """
    sl = SymbolLibrary()
    sl.symbols = copy.deepcopy(self.symbols)
    sl.preamble = copy.deepcopy(self.preamble)
    sl.num_variables = self.num_variables
    return sl