working - moved to compose

garminsync/fit_processor/gear_analyzer.py

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+import numpy as np
+
+class SinglespeedAnalyzer:
+    def __init__(self):
+        self.chainring_options = [38, 46]  # teeth
+        self.common_cogs = list(range(11, 28))  # 11t to 27t rear cogs
+        self.wheel_circumference_m = 2.096  # 700x25c tire
+    
+    def analyze_gear_ratio(self, speed_data, cadence_data, gradient_data):
+        """Determine most likely singlespeed gear ratio"""
+        # Validate input parameters
+        if not speed_data or not cadence_data or not gradient_data:
+            raise ValueError("Input data cannot be empty")
+        if len(speed_data) != len(cadence_data) or len(speed_data) != len(gradient_data):
+            raise ValueError("Input data arrays must be of equal length")
+            
+        # Filter for flat terrain segments (gradient < 3%)
+        flat_indices = [i for i, grad in enumerate(gradient_data) if abs(grad) < 3.0]
+        flat_speeds = [speed_data[i] for i in flat_indices]
+        flat_cadences = [cadence_data[i] for i in flat_indices]
+        
+        # Only consider data points with sufficient speed (15 km/h) and cadence
+        valid_indices = [i for i in range(len(flat_speeds)) 
+                         if flat_speeds[i] > 4.17 and flat_cadences[i] > 0]  # 15 km/h threshold
+        
+        if not valid_indices:
+            return None  # Not enough data
+        
+        valid_speeds = [flat_speeds[i] for i in valid_indices]
+        valid_cadences = [flat_cadences[i] for i in valid_indices]
+        
+        # Calculate gear ratios from speed and cadence
+        gear_ratios = []
+        for speed, cadence in zip(valid_speeds, valid_cadences):
+            # Gear ratio = (speed in m/s * 60 seconds/minute) / (cadence in rpm * wheel circumference in meters)
+            gr = (speed * 60) / (cadence * self.wheel_circumference_m)
+            gear_ratios.append(gr)
+        
+        # Calculate average gear ratio
+        avg_gear_ratio = sum(gear_ratios) / len(gear_ratios)
+        
+        # Find best matching chainring and cog combination
+        best_fit = None
+        min_diff = float('inf')
+        for chainring in self.chainring_options:
+            for cog in self.common_cogs:
+                theoretical_ratio = chainring / cog
+                diff = abs(theoretical_ratio - avg_gear_ratio)
+                if diff < min_diff:
+                    min_diff = diff
+                    best_fit = (chainring, cog, theoretical_ratio)
+        
+        if not best_fit:
+            return None
+        
+        chainring, cog, ratio = best_fit
+        
+        # Calculate gear metrics
+        wheel_diameter_inches = 27.0  # 700c wheel diameter
+        gear_inches = ratio * wheel_diameter_inches
+        development_meters = ratio * self.wheel_circumference_m
+        
+        # Calculate confidence score (1 - relative error)
+        confidence = max(0, 1 - (min_diff / ratio)) if ratio > 0 else 0
+        
+        return {
+            'estimated_chainring_teeth': chainring,
+            'estimated_cassette_teeth': cog,
+            'gear_ratio': ratio,
+            'gear_inches': gear_inches,
+            'development_meters': development_meters,
+            'confidence_score': confidence
+        }