import re
from numbers import Number
from sympy import sympify
from sympy.core.sympify import SympifyError
from sympy import Min, Max, Add, Symbol, Expr, Basic # TODO: Add sqrt, pow
from pyfemtet._util.symbol_support_for_param_name import convert_symbols
__all__ = [
'_ExpressionFromString', 'InvalidExpression', 'SympifyError'
]
def _convert(expr_str):
""" \" で囲まれた部分があれば記号を置き換える """
def repl(m: re.Match) -> str:
inner = m.group(1)
return f'"{convert_symbols(inner)}"'
# 非貪欲で " 内だけを拾う
expr_str = re.sub(r'"(.+?)"', repl, expr_str)
# " を消す
expr_str = expr_str.replace('"', '')
return expr_str
[docs]
class InvalidExpression(Exception):
pass
def get_valid_functions(values_may_be_used_in_mean: dict[str, Number] = None):
v = values_may_be_used_in_mean or {}
return {
'mean': lambda *args: Add(*args).subs(v) / len(args),
'max': Max,
'min': Min,
'S': Symbol('S')
}
class _ExpressionFromString:
_expr_str: str
_sympy_expr: Expr
def __init__(
self,
expression_string: str | Number = None,
sympy_expr: Expr = None,
):
"""
Raises:
SympifyError: Sympy が認識できない場合
InvalidExpression: Sympy は認識できるが PyFemtet で想定する型ではない場合（tuple など）
Examples:
e = Expression('1')
e.expr # '1'
e.value # 1.0
e = Expression(1)
e.expr # '1'
e.value # 1.0
e = Expression('a')
e.expr # 'a'
e.value # ValueError
e = Expression('1/2')
e.expr # '1/2'
e.value # 0.5
e = Expression('1.0000')
e.expr # '1.0'
e.value # 1.0
# To use "-", "@" and "." for name
e = Expression('"Sample-1.0@Part1" * 2')
e.expr # 'Sample_hyphen_1_dot_0_at_Part1 * 2'
"""
# check
assert not (expression_string is None and sympy_expr is None)
if sympy_expr is not None:
assert expression_string is None
self._sympy_expr = sympy_expr
self._expr_str = str(sympy_expr)
else:
assert expression_string is not None
self._expr_str: str = _convert(str(expression_string))
# max(name1, name2) など関数を入れる際に問題になるので
# 下記の仕様は廃止、使い方として数値桁区切り , を入れてはいけない
# # sympify 時に tuple 扱いになるので , を置き換える
# # 日本人が数値に , を使うとき Python では _ を意味する
# # expression に _ が入っていても構わない
# tmp_expr = str(self._expr_str).replace(',', '_')
self._sympy_expr = sympify(self._expr_str, locals=get_valid_functions()) # noqa
if not isinstance(self._sympy_expr, Basic):
raise InvalidExpression(f'{self._expr_str} は数式ではありません。')
@property
def dependency(self) -> set[str]:
s: Symbol
return {s.name for s in self._sympy_expr.free_symbols}
def is_number(self) -> bool:
return self._sympy_expr.is_number
def is_expression(self) -> bool:
return not self.is_number()
@property
def expression_string(self) -> str:
return self._expr_str
def eval(self, dependency_values: dict[str, Number]):
# 型チェック
assert all([isinstance(value, Number) for value
in dependency_values.values()]), \
'ExpressionFromString では数値変数のみをサポートしています。'
re_sympy_expr = sympify( # noqa
self.expression_string,
locals=get_valid_functions(dependency_values),
)
evaluated_sympy_obj = re_sympy_expr.subs(dependency_values) # noqa
try:
evaluated_value = float(evaluated_sympy_obj)
except (ValueError, TypeError) as e:
raise type(e)(*e.args, f'{evaluated_sympy_obj=} cannot convert to float.') from None
return evaluated_value