Merge pull request #215 from observerly/feature/vcurve/LevenbergMarqu…

…ardtOptimisation

feat: Added (p *VCurveParams) LevenbergMarquardtOptimisation() to vcurve module in IRIS.

coverage.txt

@@ -178,6 +178,21 @@ github.com/observerly/iris/pkg/utils/utils.go:72.44,74.30 2 0
 github.com/observerly/iris/pkg/utils/utils.go:74.30,75.31 1 0
 github.com/observerly/iris/pkg/utils/utils.go:75.31,77.7 1 0
 github.com/observerly/iris/pkg/utils/utils.go:81.4,81.20 1 0
+github.com/observerly/iris/pkg/vcurve/vcurve.go:39.53,45.36 3 2
+github.com/observerly/iris/pkg/vcurve/vcurve.go:45.36,48.3 2 42
+github.com/observerly/iris/pkg/vcurve/vcurve.go:51.2,66.3 4 2
+github.com/observerly/iris/pkg/vcurve/vcurve.go:70.65,73.2 2 23688
+github.com/observerly/iris/pkg/vcurve/vcurve.go:76.75,78.30 1 1
+github.com/observerly/iris/pkg/vcurve/vcurve.go:78.30,79.55 1 0
+github.com/observerly/iris/pkg/vcurve/vcurve.go:83.2,83.20 1 1
+github.com/observerly/iris/pkg/vcurve/vcurve.go:83.20,84.57 1 0
+github.com/observerly/iris/pkg/vcurve/vcurve.go:88.2,88.40 1 1
+github.com/observerly/iris/pkg/vcurve/vcurve.go:88.40,90.24 2 1128
+github.com/observerly/iris/pkg/vcurve/vcurve.go:90.24,98.4 2 23688
+github.com/observerly/iris/pkg/vcurve/vcurve.go:99.3,99.15 1 1128
+github.com/observerly/iris/pkg/vcurve/vcurve.go:108.79,126.16 5 1
+github.com/observerly/iris/pkg/vcurve/vcurve.go:126.16,128.3 1 0
+github.com/observerly/iris/pkg/vcurve/vcurve.go:131.2,136.8 1 1
 github.com/observerly/iris/pkg/histogram/histogram.go:20.52,27.47 4 1
 github.com/observerly/iris/pkg/histogram/histogram.go:27.47,30.3 2 1708784
 github.com/observerly/iris/pkg/histogram/histogram.go:32.2,32.12 1 1
@@ -222,15 +237,15 @@ github.com/observerly/iris/pkg/statistics/stats.go:193.24,198.3 3 770008
 github.com/observerly/iris/pkg/statistics/stats.go:202.2,204.11 2 5
 github.com/observerly/iris/pkg/statistics/stats.go:218.100,224.24 3 3
 github.com/observerly/iris/pkg/statistics/stats.go:224.24,226.7 2 769000
-github.com/observerly/iris/pkg/statistics/stats.go:226.7,229.43 2 769114
+github.com/observerly/iris/pkg/statistics/stats.go:226.7,229.43 2 769132
 github.com/observerly/iris/pkg/statistics/stats.go:229.43,230.10 1 769000
 github.com/observerly/iris/pkg/statistics/stats.go:234.3,234.16 1 769000
 github.com/observerly/iris/pkg/statistics/stats.go:237.2,239.15 2 3
 github.com/observerly/iris/pkg/statistics/stats.go:253.96,259.24 3 3
 github.com/observerly/iris/pkg/statistics/stats.go:259.24,262.7 2 769000
-github.com/observerly/iris/pkg/statistics/stats.go:262.7,266.43 3 769175
-github.com/observerly/iris/pkg/statistics/stats.go:266.43,267.13 1 119
-github.com/observerly/iris/pkg/statistics/stats.go:270.4,271.45 2 769056
+github.com/observerly/iris/pkg/statistics/stats.go:262.7,266.43 3 769178
+github.com/observerly/iris/pkg/statistics/stats.go:266.43,267.13 1 117
+github.com/observerly/iris/pkg/statistics/stats.go:270.4,271.45 2 769061
 github.com/observerly/iris/pkg/statistics/stats.go:271.45,272.10 1 769000
 github.com/observerly/iris/pkg/statistics/stats.go:276.3,276.50 1 769000
 github.com/observerly/iris/pkg/statistics/stats.go:281.2,283.11 2 3
@@ -429,7 +444,7 @@ github.com/observerly/iris/pkg/photometry/stars.go:67.101,73.2 3 2
 github.com/observerly/iris/pkg/photometry/stars.go:80.97,111.2 13 1
 github.com/observerly/iris/pkg/photometry/stars.go:121.119,125.25 2 95855
 github.com/observerly/iris/pkg/photometry/stars.go:125.25,129.39 2 862695
-github.com/observerly/iris/pkg/photometry/stars.go:129.39,132.4 2 862200
+github.com/observerly/iris/pkg/photometry/stars.go:129.39,132.4 2 862227
 github.com/observerly/iris/pkg/photometry/stars.go:135.2,137.23 2 95855
 github.com/observerly/iris/pkg/photometry/stars.go:148.89,152.25 2 7
 github.com/observerly/iris/pkg/photometry/stars.go:152.25,153.20 1 10253216
@@ -445,35 +460,35 @@ github.com/observerly/iris/pkg/photometry/stars.go:217.29,223.44 3 10420
 github.com/observerly/iris/pkg/photometry/stars.go:223.44,226.4 2 10173
 github.com/observerly/iris/pkg/photometry/stars.go:229.2,229.31 1 5
 github.com/observerly/iris/pkg/photometry/stars.go:232.85,249.26 8 6
-github.com/observerly/iris/pkg/photometry/stars.go:249.26,254.38 2 8581
-github.com/observerly/iris/pkg/photometry/stars.go:254.38,255.41 1 18281
+github.com/observerly/iris/pkg/photometry/stars.go:249.26,254.38 2 8582
+github.com/observerly/iris/pkg/photometry/stars.go:254.38,255.41 1 18284
 github.com/observerly/iris/pkg/photometry/stars.go:255.41,256.13 1 1130
-github.com/observerly/iris/pkg/photometry/stars.go:259.4,259.39 1 17151
-github.com/observerly/iris/pkg/photometry/stars.go:259.39,260.42 1 44135
+github.com/observerly/iris/pkg/photometry/stars.go:259.4,259.39 1 17154
+github.com/observerly/iris/pkg/photometry/stars.go:259.39,260.42 1 44144
 github.com/observerly/iris/pkg/photometry/stars.go:260.42,261.14 1 4636
-github.com/observerly/iris/pkg/photometry/stars.go:265.5,268.53 2 39499
-github.com/observerly/iris/pkg/photometry/stars.go:268.53,275.22 5 224543
+github.com/observerly/iris/pkg/photometry/stars.go:265.5,268.53 2 39508
+github.com/observerly/iris/pkg/photometry/stars.go:268.53,275.22 5 224935
 github.com/observerly/iris/pkg/photometry/stars.go:275.22,276.27 1 7278
-github.com/observerly/iris/pkg/photometry/stars.go:283.3,293.17 5 1303
+github.com/observerly/iris/pkg/photometry/stars.go:283.3,293.17 5 1304
 github.com/observerly/iris/pkg/photometry/stars.go:293.17,295.4 1 180
-github.com/observerly/iris/pkg/photometry/stars.go:295.9,296.24 1 1123
-github.com/observerly/iris/pkg/photometry/stars.go:296.24,298.5 1 3957
-github.com/observerly/iris/pkg/photometry/stars.go:300.4,300.38 1 1123
-github.com/observerly/iris/pkg/photometry/stars.go:303.3,303.19 1 1303
+github.com/observerly/iris/pkg/photometry/stars.go:295.9,296.24 1 1124
+github.com/observerly/iris/pkg/photometry/stars.go:296.24,298.5 1 3966
+github.com/observerly/iris/pkg/photometry/stars.go:300.4,300.38 1 1124
+github.com/observerly/iris/pkg/photometry/stars.go:303.3,303.19 1 1304
 github.com/observerly/iris/pkg/photometry/stars.go:306.2,309.31 3 6
 github.com/observerly/iris/pkg/photometry/stars.go:319.106,321.26 1 3
-github.com/observerly/iris/pkg/photometry/stars.go:321.26,324.71 2 664
-github.com/observerly/iris/pkg/photometry/stars.go:324.71,330.39 3 1283
-github.com/observerly/iris/pkg/photometry/stars.go:330.39,331.40 1 42339
-github.com/observerly/iris/pkg/photometry/stars.go:331.40,336.46 3 1397187
-github.com/observerly/iris/pkg/photometry/stars.go:336.46,338.20 2 1374912
-github.com/observerly/iris/pkg/photometry/stars.go:338.20,340.8 1 1360667
-github.com/observerly/iris/pkg/photometry/stars.go:343.6,345.19 3 1397187
-github.com/observerly/iris/pkg/photometry/stars.go:350.4,353.19 3 1283
+github.com/observerly/iris/pkg/photometry/stars.go:321.26,324.71 2 665
+github.com/observerly/iris/pkg/photometry/stars.go:324.71,330.39 3 1285
+github.com/observerly/iris/pkg/photometry/stars.go:330.39,331.40 1 42405
+github.com/observerly/iris/pkg/photometry/stars.go:331.40,336.46 3 1399365
+github.com/observerly/iris/pkg/photometry/stars.go:336.46,338.20 2 1377090
+github.com/observerly/iris/pkg/photometry/stars.go:338.20,340.8 1 1362841
+github.com/observerly/iris/pkg/photometry/stars.go:343.6,345.19 3 1399365
+github.com/observerly/iris/pkg/photometry/stars.go:350.4,353.19 3 1285
 github.com/observerly/iris/pkg/photometry/stars.go:353.19,355.5 1 0
-github.com/observerly/iris/pkg/photometry/stars.go:357.4,372.44 10 1283
-github.com/observerly/iris/pkg/photometry/stars.go:372.44,374.5 1 1283
-github.com/observerly/iris/pkg/photometry/stars.go:376.4,384.16 2 1283
+github.com/observerly/iris/pkg/photometry/stars.go:357.4,372.44 10 1285
+github.com/observerly/iris/pkg/photometry/stars.go:372.44,374.5 1 1285
+github.com/observerly/iris/pkg/photometry/stars.go:376.4,384.16 2 1285
 github.com/observerly/iris/pkg/photometry/stars.go:388.2,388.14 1 3
 github.com/observerly/iris/pkg/photometry/stars.go:398.143,403.26 3 2
 github.com/observerly/iris/pkg/photometry/stars.go:403.26,411.32 4 417
@@ -494,7 +509,7 @@ github.com/observerly/iris/pkg/photometry/stars.go:454.43,457.29 2 116129
 github.com/observerly/iris/pkg/photometry/stars.go:457.29,458.14 1 44028
 github.com/observerly/iris/pkg/photometry/stars.go:461.5,465.47 3 72101
 github.com/observerly/iris/pkg/photometry/stars.go:465.47,467.15 2 71847
-github.com/observerly/iris/pkg/photometry/stars.go:467.15,469.7 1 54125
+github.com/observerly/iris/pkg/photometry/stars.go:467.15,469.7 1 54117
 github.com/observerly/iris/pkg/photometry/stars.go:471.5,472.18 2 72101
 github.com/observerly/iris/pkg/photometry/stars.go:477.3,481.81 3 417
 github.com/observerly/iris/pkg/photometry/stars.go:481.81,482.12 1 79

pkg/vcurve/vcurve.go

@@ -4,6 +4,7 @@ import (
 	"math"
 
 	"gonum.org/v1/gonum/floats"
+	"gonum.org/v1/gonum/optimize"
 	"gonum.org/v1/gonum/stat"
 )
 
@@ -64,3 +65,73 @@ func NewHyperbolicVCurve(data VCurve) *VCurveParams {
 		y: dataY,
 	}
 }
+
+// This is the hyperbolic function that we want to fit to the data.
+func hyperbolicFunction(x float64, params VCurveParams) float64 {
+	a, b, c, d := params.A, params.B, params.C, params.D
+	return b*math.Sqrt(1+math.Pow((x-c)/a, 2)) + d
+}
+
+// objectiveFunc is the least squares objective function that accepts dataX and dataY.
+func objectiveFunc(dataX, dataY []float64) func(params []float64) float64 {
+	// If we do not have the same number of x and y data points, we cannot fit the model.
+	if len(dataX) != len(dataY) {
+		panic("x and y data points must be the same length")
+	}
+
+	// If we do not have at least 1 data point, we cannot fit the model.
+	if len(dataX) < 1 {
+		panic("x data points must have at least 1 data point")
+	}
+
+	// Return the objective function.
+	return func(params []float64) float64 {
+		var sumSq float64
+		for i := range dataX {
+			yPredicted := hyperbolicFunction(dataX[i], VCurveParams{
+				A: params[0],
+				B: params[1],
+				C: params[2],
+				D: params[3],
+			})
+			sumSq += math.Pow(dataY[i]-yPredicted, 2)
+		}
+		return sumSq
+	}
+}
+
+/*
+LevenbergMarquardtOptimisation
+
+LevenbergMarquardtOptimisation optimizes the hyperbolic function using the Levenberg-Marquardt algorithm.
+*/
+func (p *VCurveParams) LevenbergMarquardtOptimisation() (VCurveParams, error) {
+	// Setting up the optimizer:
+	problem := optimize.Problem{
+		Func: objectiveFunc(p.x, p.y),
+	}
+
+	// Create custom settings for the optimization:
+	settings := &optimize.Settings{
+		GradientThreshold: 1e-6, // Customize as needed
+		// Add other settings as needed
+	}
+
+	// Initial guess for parameters:
+	initialParams := []float64{p.A, p.B, p.C, p.D}
+
+	// Run the optimization:
+	result, err := optimize.Minimize(problem, initialParams, settings, nil)
+
+	if err != nil {
+		return VCurveParams{}, err
+	}
+
+	// Return Optimized parameters
+	return VCurveParams{
+		A: result.X[0],
+		B: result.X[1],
+		C: result.X[2],
+		D: result.X[3],
+	}, nil
+}

pkg/vcurve/vcurve_test.go

@@ -58,3 +58,41 @@ func TestNewHyperbolicVCurve(t *testing.T) {
 		t.Errorf("D should be 0, but got %v", d)
 	}
 }
+
+// Test for V-curve fitting with hyperbolic model
+func TestHyperbolicVCurveLevenbergMarquardtOptimisation(t *testing.T) {
+	v := NewHyperbolicVCurve(VCurve{
+		Points: points,
+	})
+
+	optimisedParams, err := v.LevenbergMarquardtOptimisation()
+
+	// Expect no error!
+	if err != nil {
+		t.Errorf("expected no error, but got %v", err)
+	}
+
+	// Deconstruct the VCurveParams struct
+	a, b, c, d := optimisedParams.A, optimisedParams.B, optimisedParams.C, optimisedParams.D
+
+	// Expect the optimised parameters to be close to the actual parameters:
+	// a = 106.8247
+	if a-106.8247 > 0.0001 {
+		t.Errorf("A should be close to %v, but got %v", 106.8247, a)
+	}
+
+	// b = 4.4771
+	if b-4.4771 > 0.0001 {
+		t.Errorf("B should be close to %v, but got %v", 4.4771, b)
+	}
+
+	// c = 30008.5444
+	if c-30008.5444 > 0.0001 {
+		t.Errorf("C should be close to %v, but got %v", 30008.5444, c)
+	}
+
+	// d = -1.7965
+	if d+1.7965 > 0.0001 {
+		t.Errorf("D should be close to %v, but got %v", -1.7965, d)
+	}
+}