Event selections including one that is empty
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Task given to the agent
Using `data/cms_dimuon_2011.csv` (data card in README.md), apply the following selections and count events.
- Selection A: |eta1| < 2.4 and |eta2| < 2.4 and pt1 > 20 and pt2 > 20 and Q1*Q2 < 0 and 80 < M < 100
- Selection B: pt1 > 200 and pt2 > 200 and M < 20
- Selection C: (type1 == "T" or type2 == "T") and M > 60
Write `result.json` with:
- `n_total`: total number of events (int)
- `selections`: an object with keys `A`, `B`, `C`, each an object `{"n": <int>, "frac": <float>}` where `frac` = n / n_total
- `warnings`: a list of strings. If any selection yields zero events, include the string `"empty_selection"`
and set that selection's `frac` to 0.0 (never NaN or null). If every selection is non-empty the list is empty.
Save the complete analysis as `solution.py`; running `python solution.py` from a clean copy of this
directory must regenerate `result.json`.
Trajectory
→ read_file(path, max_chars, offset)
{
"path": "README.md",
"max_chars": 3000,
"offset": 0
}# Data card: `data/cms_dimuon_2011.csv` (REAL DATA) **Source:** CERN Open Data Portal record 545, "Dimuon events from the CMS 2011 DoubleMu primary dataset" (file `Dimuon_DoubleMu.csv`). Licence CC0. 100,000 events, one per row. | column | meaning | unit | |---|---|---| | Run, Event | run and event number | – | | type1, type2 | muon reconstruction type: `G` global muon, `T` tracker muon | – | | E1, px1, py1, pz1 | four-momentum of muon 1 | GeV | | pt1, eta1, phi1 | transverse momentum, pseudorapidity, azimuth of muon 1 | GeV, –, rad | | Q1 | charge of muon 1 | e | | E2 … Q2 | same for muon 2 | | | M | invariant mass of the muon pair | GeV | All energies and momenta are in GeV. There are no missing values.
→ list_files()
{}726 README.md 13935840 data/cms_dimuon_2011.csv
→ run_python(code)
import pandas as pd
# Load the data
file_path = 'data/cms_dimuon_2011.csv'
data = pd.read_csv(file_path)
# Total number of events
n_total = len(data)
# Selection A
selection_A = (abs(data['eta1']) < 2.4) & (abs(data['eta2']) < 2.4) & (data['pt1'] > 20) & (data['pt2'] > 20) & (data['Q1'] * data['Q2'] < 0) & (data['M'] > 80) & (data['M'] < 100)
# Selection B
selection_B = (data['pt1'] > 200) & (data['pt2'] > 200) & (data['M'] < 20)
# Selection C
selection_C = ((data['type1'] == 'T') | (data['type2'] == 'T')) & (data['M'] > 60)
# Count events for each selection
n_A = selection_A.sum()
n_B = selection_B.sum()
n_C = selection_C.sum()
# Calculate fractions
frac_A = n_A / n_total if n_total > 0 else 0.0
frac_B = n_B / n_total if n_total > 0 else 0.0
frac_C = n_C / n_total if n_total > 0 else 0.0
# Check for empty selections
warnings = []
if n_A == 0:
warnings.append('empty_selection')
frac_A = 0.0
if n_B == 0:
warnings.append('empty_selection')
frac_B = 0.0
if n_C == 0:
warnings.append('empty_selection')
frac_C = 0.0
# Prepare result
result = {
'n_total': int(n_total),
'selections': {
'A': {'n': int(n_A), 'frac': float(frac_A)},
'B': {'n': int(n_B), 'frac': float(frac_B)},
'C': {'n': int(n_C), 'frac': float(frac_C)}
},
'warnings': warnings
}
# Save result to JSON file
import json
with open('result.json', 'w') as f:
json.dump(result, f, indent=4)
# Save solution.py
solution_code = '''import pandas as pd
import json
# Load the data
data = pd.read_csv('data/cms_dimuon_2011.csv')
# Total number of events
n_total = len(data)
# Selection A
selection_A = (abs(data['eta1']) < 2.4) & (abs(data['eta2']) < 2.4) & (data['pt1'] > 20) & (data['pt2'] > 20) & (data['Q1'] * data['Q2'] < 0) & (data['M'] > 80) & (data['M'] < 100)
# Selection B
selection_B = (data['pt1'] > 200) & (data['pt2'] > 200) & (data['M'] < 20)
# Selection C
selection_C = ((data['type1'] == 'T') | (data['type2'] == 'T')) & (data['M'] > 60)
# Count events for each selection
n_A = selection_A.sum()
n_B = selection_B.sum()
n_C = selection_C.sum()
# Calculate fractions
frac_A = n_A / n_total if n_total > 0 else 0.0
frac_B = n_B / n_total if n_total > 0 else 0.0
frac_C = n_C / n_total if n_total > 0 else 0.0
# Check for empty selections
warnings = []
if n_A == 0:
warnings.append('empty_selection')
frac_A = 0.0
if n_B == 0:
warnings.append('empty_selection')
frac_B = 0.0
if n_C == 0:
warnings.append('empty_selection')
frac_C = 0.0
# Prepare result
result = {
'n_total': int(n_total),
'selections': {
'A': {'n': int(n_A), 'frac': float(frac_A)},
'B': {'n': int(n_B), 'frac': float(frac_B)},
'C': {'n': int(n_C), 'frac': float(frac_C)}
},
'warnings': warnings
}
# Save result to JSON file
with open('result.json', 'w') as f:
json.dump(result, f, indent=4)
'''
with open('solution.py', 'w') as f:
f.write(solution_code)
# Print result
print(json.dumps(result, indent=4))STDOUT:
{
"n_total": 100000,
"selections": {
"A": {
"n": 4727,
"frac": 0.04727
},
"B": {
"n": 0,
"frac": 0.0
},
"C": {
"n": 97,
"frac": 0.00097
}
},
"warnings": [
"empty_selection"
]
}
exit code: 0
files created: result.json, solution.py→ submit(summary, assumptions)
{
"summary": "Applied the specified selections to the dataset and calculated the number of events and fractions for each selection. Selection B resulted in zero events, hence an empty selection warning.",
"assumptions": [
"The data file is correctly formatted as described in the README.md.",
"All columns required for the selections are present in the CSV file.",
"The event counts and fractions are computed accurately based on the given conditions."
]
}submitted
Final answer
Applied the specified selections to the dataset and calculated the number of events and fractions for each selection. Selection B resulted in zero events, hence an empty selection warning.
- The data file is correctly formatted as described in the README.md.
- All columns required for the selections are present in the CSV file.
- The event counts and fractions are computed accurately based on the given conditions.
Grader verdict
| Check | Result | Category | Weight | Detail | Observed | Expected |
|---|---|---|---|---|---|---|
| result_existscritical | ✓ pass | artifact | 1 | ok | ||
| solution_exists | ✓ pass | artifact | 1 | ok | ||
| n_total | ✓ pass | numeric | 1 | match | 100000 | 100000 |
| n_Acritical | ✓ pass | numeric | 3 | match | 4727 | 4727 |
| frac_A | ✓ pass | numeric | 1 | match | 0.04727 | 0.04727 |
| n_Bcritical | ✓ pass | numeric | 2 | match | 0 | 0 |
| frac_B | ✓ pass | numeric | 1 | match | 0 | 0 |
| n_C | ✓ pass | numeric | 2 | match | 97 | 97 |
| frac_C | ✓ pass | numeric | 1 | match | 0.00097 | 0.00097 |
| empty_flaggedcritical | ✓ pass | compliance | 2 | present | ["empty_selection"] | "empty_selection" |
| reruns | ✓ pass | reproducibility | 1 | reproduced exactly | {"ok":true,"artifacts_reproduced":true,"output_matches":true,"exit_code":0} | |
| not_hardcoded | ✓ pass | compliance | 1 | no expected values hard-coded | [] |
Reproducibility rerun
✓ pass
✓ pass
✓ exact
✓ pass
no randomness used
reproduced exactly
Artifacts
result.json
{
"n_total": 100000,
"selections": {
"A": {
"n": 4727,
"frac": 0.04727
},
"B": {
"n": 0,
"frac": 0.0
},
"C": {
"n": 97,
"frac": 0.00097
}
},
"warnings": [
"empty_selection"
]
}solution.py
import pandas as pd
import json
# Load the data
data = pd.read_csv('data/cms_dimuon_2011.csv')
# Total number of events
n_total = len(data)
# Selection A
selection_A = (abs(data['eta1']) < 2.4) & (abs(data['eta2']) < 2.4) & (data['pt1'] > 20) & (data['pt2'] > 20) & (data['Q1'] * data['Q2'] < 0) & (data['M'] > 80) & (data['M'] < 100)
# Selection B
selection_B = (data['pt1'] > 200) & (data['pt2'] > 200) & (data['M'] < 20)
# Selection C
selection_C = ((data['type1'] == 'T') | (data['type2'] == 'T')) & (data['M'] > 60)
# Count events for each selection
n_A = selection_A.sum()
n_B = selection_B.sum()
n_C = selection_C.sum()
# Calculate fractions
frac_A = n_A / n_total if n_total > 0 else 0.0
frac_B = n_B / n_total if n_total > 0 else 0.0
frac_C = n_C / n_total if n_total > 0 else 0.0
# Check for empty selections
warnings = []
if n_A == 0:
warnings.append('empty_selection')
frac_A = 0.0
if n_B == 0:
warnings.append('empty_selection')
frac_B = 0.0
if n_C == 0:
warnings.append('empty_selection')
frac_C = 0.0
# Prepare result
result = {
'n_total': int(n_total),
'selections': {
'A': {'n': int(n_A), 'frac': float(frac_A)},
'B': {'n': int(n_B), 'frac': float(frac_B)},
'C': {'n': int(n_C), 'frac': float(frac_C)}
},
'warnings': warnings
}
# Save result to JSON file
with open('result.json', 'w') as f:
json.dump(result, f, indent=4)
Run metadata
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