private var texEncoder: TextEncoder?

mutating func load_text_encoder() {

guard let path = Bundle.main.path(forResource: "CoreMLModels", ofType: nil, inDirectory: nil) else {

fatalError("Fatal error: failed to find the CoreML models.")

}

let resourceURL = URL(fileURLWithPath: path)

// TODO: move the pipeline creation to background task because it's heavy

let encoder = try! TextEncoder(resourcesAt: resourceURL)

texEncoder = encoder

}

func text_embedding(prompt: String) -> MLShapedArray<Float32> {

let emb = try! texEncoder?.computeTextEmbedding(prompt: prompt)

return emb!

}

func cosine_similarity(A: MLShapedArray<Float32>, B: MLShapedArray<Float32>) async -> Float {

let magnitude = vDSP.sumOfSquares(A.scalars).squareRoot() * vDSP.sumOfSquares(B.scalars).squareRoot()

let dotarray = vDSP.dot(A.scalars, B.scalars)

return dotarray / magnitude

}

func spherical_dist_loss(A: MLShapedArray<Float32>, B: MLShapedArray<Float32>) async -> Float {

let a = vDSP.divide(A.scalars, sqrt(vDSP.sumOfSquares(A.scalars)))

let b = vDSP.divide(B.scalars, sqrt(vDSP.sumOfSquares(B.scalars)))

let magnitude = sqrt(vDSP.sumOfSquares(vDSP.subtract(a, b)))

return pow(asin(magnitude / 2.0), 2) * 2.0

}