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add mathematical solver engine based on sympy

master
Florin Tobler 6 months ago
parent
commit
fe9c738891
  1. 130
      math_ast.py
  2. 108
      math_interpreter.py
  3. 61
      math_lexer.py
  4. 12
      tests/test_tool_function_decorator.py
  5. 57
      tests/test_tool_functions.py
  6. 57
      tool_functions.py
  7. 1
      tool_helper.py

130
math_ast.py

@ -0,0 +1,130 @@
import math_lexer as lexer
from math_lexer import Token
class Statement:
pass
class Expression(Statement):
def __init__(self, value: str):
self.value = value
class Equation:
def __init__(self, lhs: Expression, rhs: Expression):
self.lhs = lhs
self.rhs = rhs
class Solve(Statement):
def __init__(self, equations: list[Equation], variables: list[Expression]):
self.equations = equations
self.variables = variables
class Parser:
def __init__(self):
self.tokens: list[Token] # tokens from lexer
self._last_eaten = None
def not_eof(self) -> bool:
return self.tokens[0].type is not lexer.END_OF_INPUT
def at(self) -> Token:
return self.tokens[0]
def at_last(self) -> Token:
return self._last_eaten
def eat(self) -> Token:
self._last_eaten = self.tokens.pop(0)
return self._last_eaten
def backtrack(self):
if not self._last_eaten:
raise Exception("Cannot backtrack.")
self.tokens.insert(0, self._last_eaten)
self._last_eaten = None
def eat_expect(self, token_type: int | str) -> Token:
prev = self.eat()
if prev.type is not token_type:
raise Exception("expected to consume '%s' but '%s' encountered." % (str(token_type), str(prev.type)))
return prev
def at_expect(self, token_type: int | str) -> Token:
prev = self.at()
if prev.type is not token_type:
raise Exception("expected to be at '%s' but '%s' encountered." % (str(token_type), str(prev.type)))
return prev
def parse(self, tokens: list[Token]) -> Statement:
self.tokens = tokens
statement = self.parse_statement()
self.at_expect(lexer.END_OF_INPUT)
return statement
def parse_statement(self) -> Statement:
type = self.at().type
if type is lexer.SOLVE:
return self.parse_solve()
return self.parse_expression(merge_commas=True)
def parse_solve(self) -> Solve:
"""
solve x = 1 for x
solve x = y and y = 2 for x and y
"""
self.eat_expect(lexer.SOLVE)
equations = [] # list of equations
variables = [] # list of variables to solve for
while self.not_eof() and self.at().type is not lexer.FOR:
equations.append(self.parse_equation())
selfattype = self.at().type
if selfattype is lexer.AND or selfattype is lexer.COMMA:
self.eat()
self.eat_expect(lexer.FOR)
while self.not_eof():
variables.append(self.parse_expression(merge_commas=False))
selfattype = self.at().type
if selfattype is lexer.AND or selfattype is lexer.COMMA:
self.eat()
return Solve(equations, variables)
def parse_equation(self) -> Equation:
lhs = self.parse_expression(merge_commas=False)
self.eat_expect(lexer.EQUALS)
rhs = self.parse_expression(merge_commas=False)
return Equation(lhs, rhs)
def parse_expression(self, merge_commas) -> Expression:
"""
math expression
e.g:
sin(45) / 4 * pi
"""
if merge_commas == True:
values = []
while self.not_eof():
token = self.eat()
if token.type is lexer.COMMA:
values.append(lexer.COMMA)
elif token.type is lexer.EQUALS:
values.append(lexer.EQUALS)
else:
values.append(token.value)
# token = self.eat_expect(lexer.EXPRESSION)
# values.append(token.value)
# if self.at() is lexer.COMMA:
# token = self.eat()
# values.append(lexer.COMMA)
return Expression("".join(values))
else:
token = self.eat_expect(lexer.EXPRESSION)
return Expression(token.value)

108
math_interpreter.py

@ -0,0 +1,108 @@
import math_ast as ast
from sympy.parsing.sympy_parser import parse_expr
from sympy.core.numbers import Integer, One, Zero
from sympy import symbols, Eq, solveset, linsolve, nonlinsolve
from sympy.core.symbol import Symbol
def interpret(statement: ast.Statement) -> str:
if isinstance(statement, ast.Solve):
return interpret_solve(statement)
elif isinstance(statement, ast.Expression):
return interpret_expression(statement)
return "interpretation error"
def interpret_solve(statement: ast.Solve) -> str:
eqs = statement.equations
var = statement.variables
# convert equations to list of sympy Eq objects
equations = [Eq(_math_expression_sanitation_and_parse(e.lhs.value), _math_expression_sanitation_and_parse(e.rhs.value)) for e in eqs]
variables = [symbols(v.value) for v in var]
if len(equations) == 1 and len(variables) == 1:
return solve_simple_equation(equations[0], variables[0])
else:
return solve_multi_equation(equations, variables)
def solve_simple_equation(equation, variable):
result = solveset(equation, variable)
return "solved %s = %s for %s = %s" % (equation.lhs, equation.rhs, variable, result)
def solve_multi_equation(equations, variables):
if is_linear(equations, variables):
solution = linsolve(equations, variables)
else:
solution = nonlinsolve(equations, variables)
solutionpairs = []
for variable, value in zip(variables, list(solution)[0]):
value_str = str(value)
if not isinstance(value, Integer):
try:
float_value = value.evalf()
if len(value_str) > 20:
value_str = "~%.3f" % float_value
else:
value_str += "=~%.3f" % float_value
except:
pass
solutionpairs.append(f"{variable}={value_str}")
# solutionpairs = [f"{variable}={value.doit()}" for variable, value in zip(variables, list(solution)[0])]
return "solved equation system for " + ", ".join(solutionpairs[:-1]) + " and " + solutionpairs[-1]
def is_linear(equations, variables):
return False
"""Checks if a system of equations is linear."""
for eq in equations:
for var in variables:
deriv = eq.diff(var) # Partial derivative
if not (deriv.is_number or (isinstance(deriv, Symbol) and deriv.free_symbols.isdisjoint({var}))): # If the derivative is not a number or a symbol independent of the variable, the system is non-linear
return False
return True
def interpret_expression(statement: ast.Expression) -> str:
return _math_evaluate_expression(statement.value)
def _math_evaluate_expression(expression: str):
"""evaluate a simple mathematical expression using sympy expression evaluation."""
therm, simple, result = _math_evaluate_internal(expression)
if isinstance(simple, Integer):
return _build_equation_pair([therm, simple])
if therm == simple or simple == result:
return _build_equation_pair([therm, result])
return _build_equation_pair([therm, simple, result])
def _math_evaluate_internal(expression: str):
therm = _math_expression_sanitation_and_parse(expression)
simple = therm.doit()
numerical = therm.evalf()
return therm, simple, numerical
def _math_expression_sanitation_and_parse(expression: str):
expression = expression.replace("^", "**")
return parse_expr(expression, evaluate=False)
def _build_equation_pair(expressions: list[any]) -> str:
expressions = [str(e) for e in expressions]
return " = ".join(expressions)

61
math_lexer.py

@ -0,0 +1,61 @@
EXPRESSION = 0
END_OF_INPUT = 1
SOLVE = "solve"
FOR = "for"
AND = "and"
EQUALS = "="
COMMA = ","
keyword_tokens = [SOLVE, FOR, AND, EQUALS, COMMA]
class Token:
def __init__(self, type: int|str, value: str = None):
self.type = type
self.value = value
def __repr__(self):
if self.value == None:
return f"{self.type}"
return f"{self.type}|'{self.value}'"
def tokenize(expression: str) -> list[Token]:
"""
this splits a math instruction into tokens.
example:
"solve x + 1 = 5 and y = 2*x for x, y"
result:
["solve", "x + 1", "=", "5", "and", "y", "=", "2*x", "for", "x", "and", "y", "end_of_input"]
"""
tokens = [] # output list of tokens
symbols = expression.replace(",", " , ").replace("=", " = ").split(" ")
current_token = [] # everything that is not directly in math_keyword_tokens gets binned here
for s in symbols:
found = False
for keyword in keyword_tokens:
if s.lower() == keyword:
if len(current_token) != 0:
tokens.append(Token(EXPRESSION, " ".join(current_token)))
current_token = []
tokens.append(Token(keyword))
found = True
break
if found == False:
current_token.append(s)
if len(current_token) != 0:
tokens.append(Token(EXPRESSION, " ".join(current_token)))
current_token = []
tokens.append(Token(END_OF_INPUT))
return tokens

12
tests/test_tool_function_decorator.py

@ -3,19 +3,16 @@ import tool_helper
import tests.helper as helper
def test_tool_function_decorator_if_clean_tool_list():
""" tests for the tool list to be empty. NOT strictly nessesary,
but I want to be warned if this is not the case anymore. Could be not the intention """
start_len = len(tool_helper.tool_list)
assert start_len == 0
def test_tool_function_decorator():
# get length before adding tools
start_len = len(tool_helper.tool_list)
# add tools like it would be a decorator
tool_helper.tool(helper.tool_dummy)
tool_helper.tool(helper.tool_dummy2)
res = tool_helper.tool(helper.tool_dummy)
assert res == helper.tool_dummy # decorator should return the function itself, so it is usable just in case.
res = tool_helper.tool(helper.tool_dummy2)
assert res == helper.tool_dummy2 # decorator should return the function itself, so it is usable just in case.
# get length after adding tools
end_len = len(tool_helper.tool_list)
@ -28,3 +25,4 @@ def test_tool_function_decorator():

57
tests/test_tool_functions.py

@ -0,0 +1,57 @@
import pytest
import tool_functions
def test_math_evaluate_1():
result = tool_functions.math_evaluate("1+2*pi")
assert result == "1 + 2*pi = 7.28318530717959"
def test_math_evaluate_2a():
result = tool_functions.math_evaluate("2**4")
assert result == "2**4 = 16"
def test_math_evaluate_2b():
""" test that ^ notation is also working, original sympy cannot do this """
result = tool_functions.math_evaluate("2^4")
assert result == "2**4 = 16"
def test_math_evaluate_3():
result = tool_functions.math_evaluate("Integral(exp(-x**2), (x, -oo, oo))")
assert result == "Integral(exp(-x**2), (x, -oo, oo)) = sqrt(pi) = 1.77245385090552"
def test_math_evaluate_4():
result = tool_functions.math_evaluate("(2**x)**2")
assert result == "(2**x)**2 = 2**(2*x) = 2.0**(2*x)"
def test_math_evaluate_5():
result = tool_functions.math_evaluate("sin(pi/2) + cos(0)")
assert result == "sin(pi/2) + cos(0) = 2"
def test_math_solver_1():
result = tool_functions.math_evaluate("solve x = 1 for x")
assert result == "solved x = 1 for x = {1}"
def test_math_solver_2():
result = tool_functions.math_evaluate("solve (x + 1)*(x - 1) = 1 for x")
assert result == "solved (x + 1)*(x - 1*1) = 1 for x = {-sqrt(2), sqrt(2)}"
def test_math_solver_3a():
result = tool_functions.math_evaluate("solve 2*x + 3*y = 7 and x - y = 1 for x, y")
assert result == "solved equation system for x=2 and y=1"
def test_math_solver_3b():
result = tool_functions.math_evaluate("solve 2*x + 3*y = 7, x - y = 1 for x and y")
assert result == "solved equation system for x=2 and y=1"
def test_math_solver_4():
result = tool_functions.math_evaluate("solve 2*x**3 + 3*y = 7 and x - y = 1 for x, y")
assert result == "solved equation system for x=~1.421 and y=~0.421"

57
tool_functions.py

@ -1,24 +1,29 @@
import random
import datetime
from tool_helper import tool
import math_lexer
import math_ast
import math_interpreter
@tool
def current_time():
"""Get the current local date and time as a string."""
return datetime.datetime.now().strftime("%Y-%m-%d %H:%M")
@tool
def random_float():
"""Generate a random float from 0..1."""
return str(random.random())
# @tool
# def random_float():
# """Generate a random float from 0..1."""
# return str(random.random())
# def random_float(a: float=0.0, b: float=1.0):
# """Generate a random float in range [a, b], including both end points. Optional pass no parameter and range 0..1 will be used.
# Args:
# a: minimum possible value
# b: maximum possible value"""
# return str(random.randint(a, b))
@tool
def random_float(a: float=0.0, b: float=1.0):
"""Generate a random float in range [a, b], including both end points. Optional pass no parameter and range 0..1 will be used.
Args:
a: minimum possible value
b: maximum possible value"""
return str(random.randint(a, b))
@tool
def random_int(a: int, b: int):
@ -31,5 +36,37 @@ Args:
@tool
def math_evaluate(expression: str):
"""evaluate and reduce a mathematical expression.
Args:
expression: Reduce mathematic expression (without '=') algebraically..
"""
tokens = math_lexer.tokenize(expression)
parser = math_ast.Parser()
ast = parser.parse(tokens)
return math_interpreter.interpret(ast)
@tool
def math_solve(equations: list[str], variables: list[str]):
"""evaluate a mathematical equation system and solve equation systems. Can be used to solve (x + 1)*(x - 1) = 1 for x as an example.
Args:
equations: list of mathematical equations containing a '='.
variables: list of variables to solve for. Must be lower or equal the number of given equations.
"""
expression = "solve " + " and ".join(equations) + " for " + " and ".join(variables)
print(expression)
tokens = math_lexer.tokenize(expression)
parser = math_ast.Parser()
ast = parser.parse(tokens)
return math_interpreter.interpret(ast)
def register_dummy():
pass # dummy function to run and be sure the decorators have run

1
tool_helper.py

@ -11,6 +11,7 @@ def tool(fn):
"""tool function decorator"""
print("register tool '%s'" % fn.__name__)
tool_list.append(fn)
return fn
# def parse_and_execute_tool_call(message: str, tools: list[function]) -> str | None:
# """execute tool call if needed accordint <tool_call> tag and return the content of the tool call or None if no call happened."""

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