Generator.swift

// Copyright 2019 The TensorFlow Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import Checkpoints
import Foundation
import ModelSupport
import TensorFlow

public struct NetG: Layer {
    
    // TODO: need to persist a sample generator and set this URL
    public static let remoteCheckpoint: URL =
        URL(string: "")!

    var module: UNetSkipConnectionOutermost<UNetSkipConnection<UNetSkipConnection<UNetSkipConnection<UNetSkipConnection<UNetSkipConnection<UNetSkipConnection<UNetSkipConnectionInnermost>>>>>>>
    public init(inputChannels: Int, outputChannels: Int, ngf: Int, useDropout: Bool = false) {
        let firstBlock = UNetSkipConnectionInnermost(inChannels: ngf * 8, innerChannels: ngf * 8, outChannels: ngf * 8)
        
        let module1 = UNetSkipConnection(inChannels: ngf * 8, innerChannels: ngf * 8, outChannels: ngf * 8,
                                         submodule: firstBlock, useDropOut: useDropout)
        let module2 = UNetSkipConnection(inChannels: ngf * 8, innerChannels: ngf * 8, outChannels: ngf * 8,
                                         submodule: module1, useDropOut: useDropout)
        let module3 = UNetSkipConnection(inChannels: ngf * 8, innerChannels: ngf * 8, outChannels: ngf * 8,
                                         submodule: module2, useDropOut: useDropout)

        let module4 = UNetSkipConnection(inChannels: ngf * 4, innerChannels: ngf * 8, outChannels: ngf * 4,
                                         submodule: module3, useDropOut: useDropout)
        let module5 = UNetSkipConnection(inChannels: ngf * 2, innerChannels: ngf * 4, outChannels: ngf * 2,
                                         submodule: module4, useDropOut: useDropout)
        let module6 = UNetSkipConnection(inChannels: ngf, innerChannels: ngf * 2, outChannels: ngf,
                                         submodule: module5, useDropOut: useDropout)

        self.module = UNetSkipConnectionOutermost(inChannels: inputChannels, innerChannels: ngf, outChannels: outputChannels,
                                                  submodule: module6)
    }
    
    @differentiable
    public func callAsFunction(_ input: Tensor<Float>) -> Tensor<Float> {
        return self.module(input)
    }
}