mirror of https://github.com/nucypher/pyUmbral.git
42 lines
1.2 KiB
Python
42 lines
1.2 KiB
Python
"""
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This file is part of pyUmbral.
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pyUmbral is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published b
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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pyUmbral is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with pyUmbral. If not, see <https://www.gnu.org/licenses/>.
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"""
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from typing import List
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from umbral.curvebn import CurveBN
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def lambda_coeff(id_i: CurveBN, selected_ids: List[CurveBN]) -> CurveBN:
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ids = [x for x in selected_ids if x != id_i]
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if not ids:
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return CurveBN.from_int(1, id_i.curve)
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result = ids[0] / (ids[0] - id_i)
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for id_j in ids[1:]:
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result = result * id_j / (id_j - id_i)
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return result
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def poly_eval(coeff: List[CurveBN], x: CurveBN) -> CurveBN:
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result = coeff[-1]
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for i in range(-2, -len(coeff) - 1, -1):
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result = (result * x) + coeff[i]
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return result
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