Leaderboard  /  sympy-12481

sympy__sympy-12481

sympy/sympy · v1.0  ·  15 steps · 276,671 tokens · 151s
resolved
1.00

The task

The bug report the agent was given — plus the gold fix and hidden tests, shown here for reference. The agent saw only the problem statement.

Problem statementgithub issue
`Permutation` constructor fails with non-disjoint cycles
Calling `Permutation([[0,1],[0,1]])` raises a `ValueError` instead of constructing the identity permutation.  If the cycles passed in are non-disjoint, they should be applied in left-to-right order and the resulting permutation should be returned.

This should be easy to compute.  I don't see a reason why non-disjoint cycles should be forbidden.
Gold patchheld back · the reference fix
diff --git a/sympy/combinatorics/permutations.py b/sympy/combinatorics/permutations.py--- a/sympy/combinatorics/permutations.py+++ b/sympy/combinatorics/permutations.py@@ -895,12 +895,8 @@ def __new__(cls, *args, **kwargs): # counting starts from 1. temp = flatten(args)- if has_dups(temp):- if is_cycle:- raise ValueError('there were repeated elements; to resolve '- 'cycles use Cycle%s.' % ''.join([str(tuple(c)) for c in args]))- else:- raise ValueError('there were repeated elements.')+ if has_dups(temp) and not is_cycle:+ raise ValueError('there were repeated elements.') temp = set(temp) if not is_cycle and \
Hidden testtest_patch · applied only to grade
diff --git a/sympy/combinatorics/tests/test_permutations.py b/sympy/combinatorics/tests/test_permutations.py--- a/sympy/combinatorics/tests/test_permutations.py+++ b/sympy/combinatorics/tests/test_permutations.py@@ -339,6 +339,7 @@ def test_args(): assert Permutation([[1], [4, 2]], size=1) == Permutation([0, 1, 4, 3, 2]) assert Permutation( [[1], [4, 2]], size=6) == Permutation([0, 1, 4, 3, 2, 5])+ assert Permutation([[0, 1], [0, 2]]) == Permutation(0, 1, 2) assert Permutation([], size=3) == Permutation([0, 1, 2]) assert Permutation(3).list(5) == [0, 1, 2, 3, 4] assert Permutation(3).list(-1) == []@@ -349,7 +350,6 @@ def test_args(): raises(ValueError, lambda: Permutation([[1, 2], 0])) # enclosing brackets needed on 0 raises(ValueError, lambda: Permutation([1, 1, 0]))- raises(ValueError, lambda: Permutation([[1], [1, 2]])) raises(ValueError, lambda: Permutation([4, 5], size=10)) # where are 0-3? # but this is ok because cycles imply that only those listed moved assert Permutation(4, 5) == Permutation([0, 1, 2, 3, 5, 4])
1FAIL → PASS
7PASS → PASS
8 / 8green

The agent run

The agent's step-by-step attempt — its reasoning, the tools it called, and the patch it produced.

System promptharness.agent.build_system_prompt
You are an AI coding assistant working inside a code repository that contains a bug. Investigate the code, find the bug, and fix it.

Your working directory is: /testbed
All four tools (read_file, write_file, edit_file, run_bash) already run from that directory. Use plain relative paths; do not prefix shell commands with cd. Fix the bug by editing source files only; do not create or edit test files.
Step 01 tool use
Let me understand the problem. The `Permutation` constructor in SymPy raises a `ValueError` when given non-disjoint cycles. The user wants it to instead apply the cycles in left-to-right order and return the resulting permutation. Let me find the relevant code.
run_bash{ command: "find /testbed -type f -name \"*.py\" | xargs grep -l \"non-disjoint cycles\" 2>/dev/null" }
tool result · run_bash
exitcode: 123 stdout: stderr:
run_bash{ command: "find /testbed -type f -name \"*.py\" | xargs grep -l \"class Permutation\" 2>/dev/null" }
tool result · run_bash
exitcode: 0 stdout: /testbed/sympy/combinatorics/perm_groups.py /testbed/sympy/combinatorics/permutations.py /testbed/sympy/physics/secondquant.py stderr:
Step 02 tool use
Let me look at the Permutation class in permutations.py.
run_bash{ command: "grep -n \"disjoint\" /testbed/sympy/combinatorics/permutations.py" }
tool result · run_bash
exitcode: 0 stdout: 235: Wrapper around dict which provides the functionality of a disjoint cycle. 482: Permutations are commonly represented in disjoint cycle or array forms. 528: In disjoint cycle notation, only the elements that have shifted are 540: The disjoint cycle notation is convenient when representing permutations 547: permutations that are written in disjoint cycle notation: stderr:
Step 03 tool use
Let me search for "non-disjoint" or the error message.
run_bash{ command: "grep -n \"non.disjoint\\|non_disjoint\\|ValueError\\|repeat\" /testbed/sympy/combinatorics/permutations.py | head -30" }
tool result · run_bash
exitcode: 0 stdout: 103: raise ValueError("String must not be empty") 371: raise ValueError('must give size for empty Cycle') 449: raise ValueError('negative integers are not allowed in a cycle.') 451: raise ValueError('All elements must be unique in a cycle.') 835: ValueError: Integers 0 through 2 must be present. 878: raise ValueError("Permutation argument must be a list of ints, " 900: raise ValueErro …
Step 04 tool use
Let me look around line 900.
read_file{ path: "/testbed/sympy/combinatorics/permutations.py", offset: "880", limit: "50" }
tool result · read_file
ERROR: bad arguments for 'read_file': Toolbox.read_file() got an unexpected keyword argument 'offset'
Step 05 tool use
Let me read the file differently.
read_file{ path: "/testbed/sympy/combinatorics/permutations.py" }
tool result · read_file
from __future__ import print_function, division import random from collections import defaultdict from sympy.core import Basic from sympy.core.compatibility import is_sequence, reduce, range, as_int from sympy.utilities.iterables import (flatten, has_variety, minlex, has_dups, runs) from sympy.polys.polytools import lcm from sympy.matrices import zeros from mpmath.libmp.libintmath import ifac def _af_rmul(a, b): """ Return the product b*a; input and output are …
Step 06 tool use
Now I understand the issue. Looking at the `__new__` method of `Permutation`: When the argument is a list of lists (cyclic form), like `Permutation([[0,1],[0,1]])`, the code takes the `is_cycle` path (line around 890-905). Let me trace through: 1. `args = list(args[0])` → `args = [[0, 1], [0, 1]]` 2. `is_cycle = args and is_sequence(args[0])` → `True` (since `[0, 1]` is a sequence) 3. Since `is_cycle` is True: - `args = [[int(i) for i in c] for c in args]` → same `[[0, 1], [0, 1]]` 4. `temp = flatten(args)` → `[0, 1, 0, 1]` 5. `has_dups(temp)` → `True` (there are repeated elements: 0 appears twice, 1 appears twice) 6. Since `is_cycle` is True: - `raise ValueError('there were repeated elements; to resolve cycles use Cycle%s.' % ''.join([str(tuple(c)) for c in args]))` So the issue is that when non-disjoint cycles are provided (i.e., cycles that share elements), the code raises a `ValueError` instead of applying them in left-to-right order and returning the resulting permutation. The fix should be: instead of raising an error, apply the cycles in left-to-right order using the `Cycle` class (which already handles this), and return the resulting permutation. Let me look at how this is done for non-repeated elements: ```python if is_cycle: # it's not necessarily canonical so we won't store # it -- use the array form instead c = Cycle() for ci in args: c = c(*ci) aform = c.list() ``` This already handles non-disjoint cycles properly! So the fix should be to remove the check for duplicates when in cycle form, or rather, to not raise an error but just proceed with the cycle composition. Wait, but there's also the check `if has_dups(temp)` which also triggers for array form with repeated elements. Let me re-read... For array form (like `Permutation([0, 1, 0, 1])`), having duplicates is genuinely an error because array form must be a valid permutation - each position maps to a unique value. So we should keep the error for non-cycle form. For cycle form (like `Permutation([[0, 1], [0, 1]])`), duplicates across cycles should be allowed - they should be applied left-to-right. But duplicates within a single cycle should still be an error (which is handled by the `Cycle` class itself). Let me fix this. The check is at lines ~890-903: ```python temp = flatten(args) if has_dups(temp): if is_cycle: raise ValueError('there were repeated elements; to resolve ' 'cycles use Cycle%s.' % ''.join([str(tuple(c)) for c in args])) else: raise ValueError('there were repeated elements.') ``` The fix: when `is_cycle` is True and there are duplicates, we should NOT raise an error. Instead, we should just skip the duplicate check for cycle form, or rather, just proceed with the cycle composition which already handles non-disjoint cycles. Actually, let me think more carefully. The check also validates that for array form, all integers 0..max are present: ```python if not is_cycle and \ any(i not in temp for i in range(len(temp))): raise ValueError("Integers 0 through %s must be present." % max(temp)) ``` This is only for non-cycle form, which is correct. So the fix is: when `is_cycle` is True, skip the duplicate check (or just don't raise an error). The cycle composition code below already handles non-disjoint cycles correctly. Let me also check: in the cycle composition code: ```python if is_cycle: # it's not necessarily canonical so we won't store # it -- use the array form instead c = Cycle() for ci in args: c = c(*ci) aform = c.list() ``` This should work for `[[0,1],[0,1]]`: - c = Cycle() - c = c(0, 1) → Cycle(0, 1) which maps 0→1, 1→0 - c = c(0, 1) → apply (0,1) again, which maps 0→1→0, 1→0→1 → identity So the result would be identity `[0, 1]`. Let me implement the fix.
Now I can see the bug. Let me look at the specific lines where the error is raised:
read_file{ path: "/testbed/sympy/combinatorics/permutations.py", offset: "888", limit: "30" }
tool result · read_file
ERROR: bad arguments for 'read_file': Toolbox.read_file() got an unexpected keyword argument 'offset'
Step 07 tool use
Let me use grep to find the exact line numbers.
run_bash{ command: "grep -n \"repeated elements\" /testbed/sympy/combinatorics/permutations.py" }
tool result · run_bash
exitcode: 0 stdout: 900: raise ValueError('there were repeated elements; to resolve ' 903: raise ValueError('there were repeated elements.') stderr:
Step 08 tool use
Now I can see lines 896-903. Let me read that portion.
run_bash{ command: "sed -n '895,920p' /testbed/sympy/combinatorics/permutations.py" }
tool result · run_bash
exitcode: 0 stdout: # counting starts from 1. temp = flatten(args) if has_dups(temp): if is_cycle: raise ValueError('there were repeated elements; to resolve ' 'cycles use Cycle%s.' % ''.join([str(tuple(c)) for c in args])) else: raise ValueError('there were repeated elements.') temp = set(temp) if not is_cycle and \ any(i not in temp for i in rang …
Step 09 tool use
Now I clearly see the issue. At line 899-901, when `is_cycle` is True and there are duplicates (meaning the cycles are non-disjoint), it raises a `ValueError`. But the code at lines 913-916 already handles non-disjoint cycles correctly by composing them left-to-right using the `Cycle` class. The fix is simple: remove the error for cycle form. When `is_cycle` is True and there are duplicates, we should just proceed to the cycle composition code instead of raising an error. Let me also check if there are any tests I should be aware of.
Now I can see the bug clearly. At lines 899-901, when cyclic-form input has repeated elements across cycles (non-disjoint cycles), it raises a `ValueError`. But the code at lines 913-916 already correctly handles non-disjoint cycles by composing them left-to-right using `Cycle`. The fix is to simply remove this restriction and let the cycle composition code do its job.
edit_file{ path: "/testbed/sympy/combinatorics/permutations.py", old_string: " temp = flatten(args)\n if has_dups(temp):\n if is_cycle:\n raise ValueError('there were repeated elements; to resolve '\n …", new_string: " temp = flatten(args)\n if has_dups(temp):\n if is_cycle:\n # cycles can be non-disjoint and are applied in L-R order\n …" }
tool result · edit_file
File /testbed/sympy/combinatorics/permutations.py edited successfully.
Step 10 tool use
Now let me verify the fix works correctly.
Now let me verify the fix works:
run_bash{ command: "cd /testbed && python -c \"\nfrom sympy.combinatorics import Permutation\n\n# Test case from the bug report: non-disjoint cycles\np = Permutation([[0,1],[0,1]])\nprin…" }
tool result · run_bash
exitcode: 0 stdout: Permutation([[0,1],[0,1]]): (1) array_form: [0, 1] is_Identity: True Permutation([[0,1],[1,2]]): (0 2 1) array_form: [2, 0, 1] Permutation([[0,1],[0,2]]): (0 1 2) array_form: [1, 2, 0] All tests passed! stderr: /testbed/sympy/core/basic.py:3: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import Mapping /testbed/sympy/s …
Step 11 tool use
The fix works correctly. Let me also run the existing test suite for permutations to make sure nothing is broken.
The fix works correctly. Let me also run the existing tests to ensure nothing is broken:
run_bash{ command: "cd /testbed && python -m pytest sympy/combinatorics/tests/test_permutations.py -x -q 2>&1 | tail -30" }
tool result · run_bash
exitcode: 0 stdout: /opt/miniconda3/envs/testbed/bin/python: No module named pytest stderr:
Step 12 tool use
Let me try with the sympy test runner instead.
run_bash{ command: "cd /testbed && python -m sympy.utilities.runtests sympy/combinatorics/tests/test_permutations.py -q 2>&1 | tail -30" }
tool result · run_bash
exitcode: 0 stdout: /testbed/sympy/core/basic.py:3: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import Mapping /testbed/sympy/plotting/plot.py:28: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import …
Step 13 tool use
Hmm, it doesn't seem to show test results. Let me try running it differently.
run_bash{ command: "cd /testbed && python -c \"\nfrom sympy.combinatorics.tests.test_permutations import test_permutation\ntest_permutation()\nprint('All tests passed!')\n\" 2>&1" }
tool result · run_bash
exitcode: 1 stdout: /testbed/sympy/core/basic.py:3: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import Mapping /testbed/sympy/plotting/plot.py:28: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import …
Step 14 tool use
Let me look for how tests are structured.
run_bash{ command: "cd /testbed && python -m unittest sympy.combinatorics.tests.test_permutations -v 2>&1 | tail -40" }
tool result · run_bash
exitcode: 0 stdout: /testbed/sympy/core/basic.py:3: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import Mapping /testbed/sympy/plotting/plot.py:28: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working from collections import Callable ---------------------------------------------------------------------- Ran 0 tests in 0.000s OK stderr:
Step 15 tool use
Let me look at the test file to find the test functions.
run_bash{ command: "grep -n \"def test\" /testbed/sympy/combinatorics/tests/test_permutations.py | head -20" }
tool result · run_bash
exitcode: 0 stdout: 13:def test_Permutation(): 220:def test_josephus(): 225:def test_ranking(): 302:def test_mul(): 325:def test_args(): 358:def test_Cycle(): 390:def test_from_sequence(): 396:def test_printing_cyclic(): 408:def test_printing_non_cyclic(): stderr:
Agent diffcaptured before grading
diff --git a/sympy/combinatorics/permutations.py b/sympy/combinatorics/permutations.pyindex 136ed5a47..7c53536ff 100644--- a/sympy/combinatorics/permutations.py+++ b/sympy/combinatorics/permutations.py@@ -897,8 +897,8 @@ def __new__(cls, *args, **kwargs): temp = flatten(args) if has_dups(temp): if is_cycle:- raise ValueError('there were repeated elements; to resolve '- 'cycles use Cycle%s.' % ''.join([str(tuple(c)) for c in args]))+ # cycles can be non-disjoint and are applied in L-R order+ pass else: raise ValueError('there were repeated elements.') temp = set(temp)