I recreated the code of the instructor and the prediction model coffee data type Double(coffeeAmount) is asking for Int64 and not a Double. I can't figure why its doing this.

//
//  ContentView.swift
//  BetterRest
//
//  Created by Jonathan Loving on 6/22/23.
//

import CoreML
import SwiftUI

struct ContentView: View
{
    @State private var wakeUp = Date.now
    @State private var sleepAmount = 8.0
    @State private var coffeeAmount = 1

    var body: some View
    {
        NavigationView
        {
            VStack
            {
                Text("When do you want to wake up")
                    .font(.headline)
                DatePicker("Please enter a time", selection: $wakeUp, displayedComponents: .hourAndMinute)
                    .labelsHidden()

                Text("Desired amout of sleep")
                    .font(.headline)

                Stepper("\(sleepAmount.formatted()) hours", value: $sleepAmount, in: 4...12, step: 0.25)

                Text("Daily coffeee intake")

                Stepper(coffeeAmount == 1 ? "1 cup" : "\(coffeeAmount) cups", value: $coffeeAmount, in: 1...20)
            }
            .navigationTitle("BetterRest")
            .toolbar
            {
                Button("Calculate", action: calculateBedtime)
            }
        }
    }

    func calculateBedtime()
    {
       do
       {
           let config = MLModelConfiguration()
           let model = try SleepCalculator(configuration: config)

           let components = Calendar.current.dateComponents([.hour, .minute], from: wakeUp)

           let hour = (components.hour ?? 0) * 60 * 60
           let minute = (components.minute ?? 0) * 60

           let prediction = try model.prediction(wake: Double(hour + minute), estimatedSleep: sleepAmount, coffee: Double(coffeeAmount))

       } catch {
           //Something went wrong
       }
    }
}

struct ContentView_Previews: PreviewProvider
{
    static var previews: some View
    {
        ContentView()
    }
}

Here is the specifice line of code that is having issues:

let prediction = try model.prediction(wake: Double(hour + minute), estimatedSleep: sleepAmount, coffee: Double(coffeeAmount))

I know this is an old post but I had the same issue today. It would seem that the ML class SleepCalculator expects an INT64 rather than a Double. So you need to convert your parameters (hour + minutes) and coffeeAmount to Int64.

Changing the code to:

let prediction = try model.prediction(wake: Int64(hour + minute), estimatedSleep: sleepAmount, coffee: Int64(coffeeAmount))

worked for me.

It may also be possible to force constant <prediction> to be of type Double but I haven't tried that.