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maximum-weight-matching
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Read from stdin when no input file specified

This commit is contained in:
Joris van Rantwijk 2023-02-19 19:44:06 +01:00
parent 83d9e37db6
commit 37aa0c605b
1 changed files with 24 additions and 25 deletions
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49
python/run_matching.py
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@ -9,6 +9,7 @@ from __future__ import annotations
import sys
import argparse
import math
import os
import os.path
from typing import Optional, TextIO
@ -30,8 +31,9 @@ def read_dimacs_graph(f: TextIO) -> list[tuple[int, int, int|float]]:
edges: list[tuple[int, int, float]] = []
for s in f:
words = s.strip().split()
for line in f:
s = line.strip()
words = s.split()
if not words[0]:
# Skip empty line.
@ -45,7 +47,7 @@ def read_dimacs_graph(f: TextIO) -> list[tuple[int, int, int|float]]:
# Handle "problem" line.
if len(words) != 4:
raise ValueError(
f"Expecting DIMACS edge format but got {s.strip()!r}")
f"Expecting DIMACS edge format but got {s!r}")
if words[1] != "edge":
raise ValueError(
f"Expecting DIMACS edge format but got {words[1]!r}")
@ -53,11 +55,13 @@ def read_dimacs_graph(f: TextIO) -> list[tuple[int, int, int|float]]:
elif words[0] == "e":
# Handle "edge" line.
if len(words) != 4:
raise ValueError(f"Expecting edge but got {s.strip()!r}")
raise ValueError(f"Expecting edge but got {s!r}")
x = int(words[1])
y = int(words[2])
if (x < 1) or (y < 1):
raise ValueError(f"Invalid vertex index {s!r}")
w = parse_int_or_float(words[3])
edges.append((x, y, w))
edges.append((x - 1, y - 1, w))
else:
raise ValueError(f"Unknown line type {words[0]!r}")
@ -89,8 +93,9 @@ def read_dimacs_matching(
weight: int|float = 0
pairs: list[tuple[int, int]] = []
for s in f:
words = s.strip().split()
for line in f:
s = line.strip()
words = s.split()
if not words[0]:
# Skip empty line.
@ -104,7 +109,7 @@ def read_dimacs_matching(
# Handle "solution" line.
if len(words) != 2:
raise ValueError(
f"Expecting solution line but got {s.strip()}")
f"Expecting solution line but got {s!r}")
if have_weight:
raise ValueError("Duplicate solution line")
have_weight = True
@ -114,10 +119,12 @@ def read_dimacs_matching(
# Handle "matching" line.
if len(words) != 3:
raise ValueError(
f"Expecting matched edge but got {s.strip()}")
f"Expecting matched edge but got {s!r}")
x = int(words[1])
y = int(words[2])
pairs.append((x, y))
if (x < 1) or (y < 1):
raise ValueError(f"Invalid vertex index {s!r}")
pairs.append((x - 1, y - 1))
else:
raise ValueError(f"Unknown line type {words[0]!r}")
@ -152,7 +159,7 @@ def write_dimacs_matching(
print("s", f"{weight:.12g}", file=f)
for (x, y) in pairs:
print("m", x, y, file=f)
print("m", x + 1, y + 1, file=f)
def write_dimacs_matching_file(
@ -324,9 +331,6 @@ def main() -> int:
parser.description = (
"Calculate maximum weighted matching of graphs in DIMACS format.")
parser.add_argument("--stdin",
action="store_true",
help="read graph from stdin")
parser.add_argument("--verify",
action="store_true",
help="verify existing output file(s)")
@ -344,24 +348,19 @@ def main() -> int:
help="directory to write output")
parser.add_argument("input",
nargs="*",
help="input file(s)")
help="input file(s); leave empty to read from stdin")
args = parser.parse_args()
if args.stdin and args.verify:
print("ERROR: Can not verify when reading from stdin",
if (not args.input) and os.isatty(sys.stdin.fileno()):
print("ERROR: Expecting input from stdin but stdin is a terminal",
file=sys.stderr)
return 1
if (not args.stdin) and (not args.input):
parser.print_help(sys.stderr)
print(file=sys.stderr)
print("ERROR: Specify either --stdin or at least one input file",
file=sys.stderr)
parser.print_help(sys.stderr)
return 1
if args.stdin and args.input:
print("ERROR: Specify either --stdin or input files, not both",
if (not args.input) and args.verify:
print("ERROR: Can not verify when reading from stdin",
file=sys.stderr)
return 1