add ios sdk and example with CoreML (#1289)

Co-authored-by: nugrahad <daniel.nugraha@pub.tech>
Co-authored-by: ge57sug <ge57sug@mytum.de>

examples/ios/Flower/.gitignore

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+.DS_Store
+/.build
+/Packages
+/*.xcodeproj
+xcuserdata/
+DerivedData/
+.swiftpm/config/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

examples/ios/Flower/Package.swift

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+// swift-tools-version: 5.6
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "Flower",
+    products: [
+        // Products define the executables and libraries a package produces, and make them visible to other packages.
+        .library(
+            name: "Flower",
+            targets: ["Flower"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+        .package(url: "https://github.com/pvieito/PythonKit.git", branch: "master"),
+        .package(url: "https://github.com/kewlbear/NumPy-iOS.git", branch: "main"),
+        .package(url: "https://github.com/grpc/grpc-swift.git", from: "1.0.0"),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages this package depends on.
+        .target(
+            name: "Flower",
+            dependencies: [
+                .product(name: "GRPC", package: "grpc-swift"),
+                .product(name: "NumPy-iOS", package: "NumPy-iOS"),
+                .product(name: "PythonKit", package: "PythonKit")],
+            path: "Sources/Flower"),
+        .testTarget(
+            name: "FlowerTests",
+            dependencies: ["Flower"]),
+    ]
+)

examples/ios/Flower/README.md

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+# Flower
+
+A description of this package.

examples/ios/Flower/Sources/Flower/Client/Client.swift

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+//
+//  Client.swift
+//  FlowerSDK
+//
+//  Created by Daniel Nugraha on 09.01.22.
+//
+
+import Foundation
+
+public protocol Client {
+    func getParameters() -> ParametersRes
+    func getProperties(ins: PropertiesIns) -> PropertiesRes
+    func fit(ins: FitIns) -> FitRes
+    func evaluate(ins: EvaluateIns) -> EvaluateRes
+}
+
+public extension Client {
+    func getProperties(ins: PropertiesIns) -> PropertiesRes {
+        return PropertiesRes(properties: [:])
+    }
+}

examples/ios/Flower/Sources/Flower/Common/Exception.swift

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+//
+//  Exception.swift
+//  FlowerSDK
+//
+//  Created by Daniel Nugraha on 09.01.22.
+//
+
+import Foundation
+
+public enum FlowerException: Error {
+    case TypeException(String)
+    case UnknownServerMessage
+}

examples/ios/Flower/Sources/Flower/Common/Parameter.swift

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+//
+//  Parameter.swift
+//  FlowerSDK
+//
+//  Created by Daniel Nugraha on 09.01.22.
+//
+
+import Foundation
+import NumPySupport
+import PythonSupport
+import PythonKit
+import CoreML
+
+@available(iOS 14.0, *)
+public class ParameterConverter {
+    var np: PythonObject
+    var io: PythonObject
+    var typing: PythonObject
+
+    private static let appDirectory = FileManager.default.urls(for: .applicationSupportDirectory,
+                                                               in: .userDomainMask).first!
+    /// The permanent location of the numpyArray.
+    private var numpyArrayUrl = appDirectory.appendingPathComponent("numpyArray.npy")
+
+    public init() {
+        PythonSupport.initialize()
+        NumPySupport.sitePackagesURL.insertPythonPath()
+        np = Python.import("numpy")
+        io = Python.import("io")
+        typing = Python.import("typing")
+    }
+
+    private func multiArrayToNumpy(multiArray: MLMultiArray) -> PythonObject? {
+        let pointer = try! UnsafeBufferPointer<Float>(multiArray)
+        let array = pointer.compactMap{$0}
+        let shape = multiArray.shape.map { Int16(truncating: $0) }
+        let filteredShape = shape.filter { $0 > 1 }
+        return array.makeNumpyArray().reshape(filteredShape)
+    }
+
+    private func numpyToData(numpy: PythonObject) -> Data? {
+        guard Python.isinstance(numpy, np.ndarray) == true else {
+            return nil
+        }
+
+        let fileManager = FileManager.default
+        if fileManager.fileExists(atPath: numpyArrayUrl.path) {
+            try? fileManager.removeItem(at: numpyArrayUrl)
+        }
+
+        np.save(numpyArrayUrl.path, numpy)
+        return try? Data(contentsOf: numpyArrayUrl)
+    }
+
+    private func dataToNumpy(data: Data) -> PythonObject? {
+        let fileManager = FileManager.default
+        if fileManager.fileExists(atPath: numpyArrayUrl.path) {
+            try? fileManager.removeItem(at: numpyArrayUrl)
+        }
+        try? data.write(to: numpyArrayUrl)
+
+        return np.load(numpyArrayUrl.path)
+    }
+
+    private func numpyToArray(numpy: PythonObject) -> [Float]? {
+        guard Python.isinstance(numpy, np.ndarray) == true else {
+            return nil
+        }
+        let flattened = numpy.flatten()
+        return Array<Float>(numpy: flattened)
+    }
+
+    private func numpyToMultiArray(numpy: PythonObject) -> MLMultiArray? {
+        guard Python.isinstance(numpy, np.ndarray) == true else {
+            return nil
+        }
+
+        let pyShape = numpy.__array_interface__["shape"]
+        guard let shape = Array<Int>(pyShape) else { return nil }
+        let shapeNSNumber = shape.map { NSNumber(value: $0) }
+
+        if let swiftArray = numpyToArray(numpy: numpy),
+           let multiArray = try? MLMultiArray(shape: shapeNSNumber, dataType: .float) {
+            for (index, element) in swiftArray.enumerated() {
+                multiArray[index] = NSNumber(value: element)
+            }
+            return multiArray
+        }
+        return nil
+    }
+
+    public func dataToMultiArray(data: Data) -> MLMultiArray? {
+        if let numpy = dataToNumpy(data: data) {
+            return numpyToMultiArray(numpy: numpy)
+        }
+        return nil
+    }
+
+    public func multiArrayToData(multiArray: MLMultiArray) -> Data? {
+        if let numpy = multiArrayToNumpy(multiArray: multiArray) {
+            return numpyToData(numpy: numpy)
+        }
+        return nil
+    }
+
+    public func dataToArray(data: Data) -> [Float]? {
+        if let numpy = dataToNumpy(data: data) {
+            return numpyToArray(numpy: numpy)
+        }
+        return nil
+    }
+
+    public func arrayToData(array: [Float], shape: [Int16]) -> Data? {
+        let numpy = array.makeNumpyArray().reshape(shape)
+        //print("before shape: \(shape)")
+        //print("after shape: \(numpy.shape)")
+        return numpyToData(numpy: numpy)
+    }
+}
+