6560300101
generate/rate_comprehension/solver.py: solve_rate computes the one unknown — quantity=rate×time (always integer), rate=quantity÷time, time=quantity÷rate (exact division or REFUSE non_integer_solution, never rounds). Confirms compound-unit composition via the R3a algebra (defensive; a RateProblem's units compose by construction). answer_unit gives the answer's unit. No floats. Ties to the gold: solves all 6 solved fixtures to gold; refuses both solver_refuses with non_integer_solution. Meaningful-fail: 100÷3 refuses (not 33), 99÷3=33. Off-serving. 5 tests.
65 lines
2.9 KiB
Python
65 lines
2.9 KiB
Python
"""Exact integer single-rate solver (R3c).
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Solves the one unknown of a ``RateProblem`` — ``quantity = rate × time`` and its two inverses —
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with **exact integer arithmetic** and a **unit-composition** confirmation:
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```text
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query quantity: quantity = rate × time (always integer)
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query rate: rate = quantity ÷ time (exact division or REFUSE)
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query time: time = quantity ÷ rate (exact division or REFUSE)
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```
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No floats, no rounding. A non-exact inverse REFUSES (``non_integer_solution``) rather than
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flooring to a wrong integer — the wrong=0 boundary. The compound-unit composition is confirmed via
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the unit algebra (R3a); since a ``RateProblem``'s units are consistent by construction, that check
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is defensive (a non-composing unit is caught earlier, at the reader). Off-serving; deterministic.
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"""
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from __future__ import annotations
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from generate.meaning_graph.reader import Refusal
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from generate.rate_comprehension.model import RateProblem
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from generate.rate_comprehension.units import (
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BaseUnit,
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RateUnit,
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UnitError,
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rate_from_quantity_over_time,
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rate_times_time,
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time_from_quantity_over_rate,
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)
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def solve_rate(problem: RateProblem) -> int | Refusal:
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"""Solve the unknown slot exactly, or refuse a non-integer inverse."""
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ru = problem.rate_unit
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try:
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if problem.query == "quantity":
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rate_times_time(ru, BaseUnit(problem.time_unit)) # confirm mile/hour × hour = mile
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assert problem.rate is not None and problem.time is not None
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return problem.rate * problem.time
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if problem.query == "rate":
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rate_from_quantity_over_time(BaseUnit(problem.quantity_unit), BaseUnit(problem.time_unit))
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assert problem.quantity is not None and problem.time is not None
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if problem.quantity % problem.time != 0:
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return Refusal("non_integer_solution", f"{problem.quantity} ÷ {problem.time} (rate)")
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return problem.quantity // problem.time
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# query == "time"
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time_from_quantity_over_rate(BaseUnit(problem.quantity_unit), ru)
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assert problem.quantity is not None and problem.rate is not None
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if problem.quantity % problem.rate != 0:
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return Refusal("non_integer_solution", f"{problem.quantity} ÷ {problem.rate} (time)")
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return problem.quantity // problem.rate
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except UnitError as exc: # pragma: no cover - a RateProblem's units compose by construction
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return Refusal("rate_unit_mismatch", str(exc))
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def answer_unit(problem: RateProblem) -> str | RateUnit:
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"""The unit of the answer to *problem* — a base unit string, or a ``RateUnit`` when asking rate."""
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if problem.query == "quantity":
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return problem.quantity_unit
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if problem.query == "time":
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return problem.time_unit
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return problem.rate_unit
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__all__ = ["answer_unit", "solve_rate"]
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