RollCalcPython/docs/STDDEV_IMPLEMENTATION_CHECKLIST.md

StdDev Ranges Implementation Checklist

📋 Quick Implementation Guide

Phase 1: Add JavaScript Modules (2 files)

# Copy to your static folder:
cp .code/rollcalc-stddev-ranges.js /path/to/flask/static/
cp .code/rollcalc-stddev-integration.js /path/to/flask/static/

Phase 2: Update HTML (3 lines changed)

In roll_calculator.html, find the section where scripts are loaded (around line ~2370):

Add after the other script tags:

<script src="/static/rollcalc-stddev-ranges.js"></script>
<script src="/static/rollcalc-stddev-integration.js"></script>

Phase 3: Update JavaScript - Article Selection

In rollcalc_improvements.js, find the populateArticleDropdowns_v14() function.

In the "DirectCalc-Article" section (~line 2340), after the existing article fill code:

ADD THESE LINES:

// NEW: Store stddev values for later use
document.getElementById('d-th').dataset.stddev = match.thickness_stddev || 0;
document.getElementById('d-aw').dataset.stddev = match.area_weight_stddev || 0;

console.log('[StdDev] Stored:', {
  thickness_stddev: match.thickness_stddev,
  area_weight_stddev: match.area_weight_stddev
});

Phase 4: Update Direct Calc Button Handler

FIND: The diameter calculation section in the d-calc click handler (~line 2380)

Replace this block:

if (mode === 'diameter') {
  if (!d_mm || !t_mm || !L_m) { alert('Please enter d, t and L.'); return; }
  const D_nom = Math.sqrt(d_mm*d_mm + (4*L_m*1000*t_mm)/Math.PI);
  resLabel.textContent = 'Roll Diameter (D)';
  resVal.textContent   = D_nom.toFixed(1) + ' mm';
  if (tol) {
    const D_min = Math.sqrt(d_mm*d_mm + (4*L_m*1000*(t_mm-tol))/Math.PI);
    const D_max = Math.sqrt(d_mm*d_mm + (4*L_m*1000*(t_mm+tol))/Math.PI);
    resRange.textContent = 'Min: ' + D_min.toFixed(1) + ' mm  |  Max: ' + D_max.toFixed(1) + ' mm';
  } else { resRange.textContent = ''; }
  document.getElementById('d-di').value = D_nom.toFixed(1);
  calculatedLength = L_m;
}

WITH THIS:

if (mode === 'diameter') {
  const result = window.StdDevIntegration.calculateDiameterWithStddev(d_mm, t_mm, null, L_m, tol);
  if (!result) return;
  
  calculatedLength = result.calculatedLength;
  
  // Calculate weight with stddev ranges
  const weightRanges = window.StdDevIntegration.calcWeightWithStddev(calculatedLength);
  
  // Forklift check uses worst-case weight
  window.StdDevIntegration.evaluateForkliftWithWorstCase(d_mm, category);
}

Phase 5: Update Weight Calculation

FIND: The calcWeight() function (~line 2410)

Replace:

function calcWeight(length) {
  const wi = parseFloat(document.getElementById('de-wi').value) || 0;
  const aw = parseFloat(document.getElementById('d-aw').value) || 0;
  if (wi > 0 && aw > 0 && length > 0) {
    const w = (aw * length * wi / 1000).toFixed(1);
    document.getElementById('d-wo').value = w;
    return parseFloat(w);
  }
  document.getElementById('d-wo').value = '';
  return null;
}

WITH:

function calcWeight(length) {
  return window.StdDevIntegration.calcWeightWithStddev(length);
}

Phase 6: Update Forklift Check Call

FIND: The line that calls ForkliftChecker.evaluate() (~line 2420)

Change from:

const allowed = runForkliftCheck(weight);

TO:

const allowed = window.StdDevIntegration.evaluateForkliftWithWorstCase(d_mm, category);

---

✅ Testing Checklist

Test 1: Article with StdDev Data

Action: Select "180005" from dropdown
Expected:
  ✓ thickness_stddev loaded (0.379181)
  ✓ area_weight_stddev loaded (133.240428)
  ✓ Console shows [StdDev] Stored message

Test 2: Diameter Calculation

Action: 
  - Select "180005"
  - Length: 50 m
  - Click Calculate
Expected:
  ✓ Result shows nominal: 502.8 mm
  ✓ Range shows: ±2σ: 491.2 – 514.4 mm
  ✓ Console shows diameter ranges

Test 3: Weight Calculation

Action: Same as Test 2
Expected:
  ✓ Weight field shows: 974.8 kg
  ✓ Data attributes set: weight_nom, weight_min, weight_max
  ✓ Worst-case weight: 1041.4 kg

Test 4: Forklift Checker

Action: Same as Test 2
Expected:
  ✓ Forklift checker uses worst-case (1041.4 kg)
  ✓ Shows appropriate warning/OK status
  ✓ Console shows [StdDev-Forklift] message

Test 5: Load Optimizer

Action: Same as Test 2, then open Load Optimizer
Expected:
  ✓ Pre-filled with nominal weight (974.8 kg)
  ✓ NOT using worst-case weight
  ✓ Calculations correct

Test 6: Backward Compatibility

Action: Manually enter values (no article selection)
Expected:
  ✓ System works as before
  ✓ Shows only nominal values
  ✓ No errors in console

---

🐛 Debugging

If something doesn't work:

1. Open DevTools (F12) → Console

2. Look for these logs:

   • [StdDev] Stored: - Article stddev loaded?
   • [StdDev-Calc] Diameter with ranges: - Calculation done?
   • [StdDev-Weight] Calculated ranges: - Weight ranges set?
   • [StdDev-Forklift] Using worst-case weight: - Forklift using right value?

3. Common issues:

   • Missing script tags → Add to HTML <head>
   • Article without stddev → Should default to 0
   • Functions undefined → Check script load order
   • Wrong values → Check browser cache (Ctrl+Shift+Delete)

---

📊 Expected Results (Example Article 180005)

Field	Value
Thickness	6.228 ± 0.758 mm (±2σ)
Area Weight	3899.02 ± 266.48 g/m² (±2σ)
Diameter @ 50m	502.8 mm (491.2–514.4 mm range)
Weight @ 5m width	974.8 kg (908.1–1041.4 kg range)
Forklift Check	Uses 1041.4 kg (worst-case)
Load Optimizer	Uses 974.8 kg (nominal)

---

📁 Files Modified

File	Changes
roll_calculator.html	Add 2 <script> tags
rollcalc_improvements.js	Add 6 lines (stddev storage)
d-calc handler	Replace diameter & weight code (~15 lines)
calcWeight()	Replace with 1-liner call
Forklift call	Change 1 line

Total changes: ~25 lines in 2 files

---

🎯 Rollback

If you need to revert:

1. Remove script tags from HTML
2. Restore original d-calc handler code (keep v14 base)
3. Restore original calcWeight() function
4. Delete stddev JavaScript files

Everything is backward compatible - no data format changes.

---

✨ You're All Set!

Follow the 6 phases above and you'll have StdDev ranges implemented in ~15 minutes! 🚀

Questions? Check STDDEV_RANGES_DOCS.md for detailed docs.