68 lines
2.0 KiB
Python
68 lines
2.0 KiB
Python
# Copyright 2010-2025 Google LLC
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""helpers methods for the cp_model module."""
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import numbers
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from typing import Any
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import numpy as np
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INT_MIN = -9223372036854775808 # hardcoded to be platform independent.
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INT_MAX = 9223372036854775807
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def is_boolean(x: Any) -> bool:
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"""Checks if the x is a boolean."""
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if isinstance(x, bool):
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return True
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if isinstance(x, np.bool_):
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return True
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return False
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def assert_is_zero_or_one(x: Any) -> int:
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"""Asserts that x is 0 or 1 and returns it as an int."""
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if not isinstance(x, numbers.Integral):
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raise TypeError(f"Not a boolean: {x} of type {type(x)}")
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x_as_int = int(x)
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if x_as_int < 0 or x_as_int > 1:
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raise TypeError(f"Not a boolean: {x}")
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return x_as_int
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def to_capped_int64(v: int) -> int:
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"""Restrict v within [INT_MIN..INT_MAX] range."""
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if v > INT_MAX:
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return INT_MAX
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if v < INT_MIN:
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return INT_MIN
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return v
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def capped_subtraction(x: int, y: int) -> int:
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"""Saturated arithmetics. Returns x - y truncated to the int64_t range."""
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if y == 0:
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return x
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if x == y:
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if x == INT_MAX or x == INT_MIN:
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raise OverflowError("Integer NaN: subtracting INT_MAX or INT_MIN to itself")
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return 0
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if x == INT_MAX or x == INT_MIN:
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return x
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if y == INT_MAX:
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return INT_MIN
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if y == INT_MIN:
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return INT_MAX
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return to_capped_int64(x - y)
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