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Solution for Poor Gradient
𝐺
𝑚𝑎𝑥 𝐸𝑧~𝑝 𝑧(𝑧) log 𝐷(𝐺 𝑧 )
𝐺
𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 )
Non-Saturating Game GANs
𝑦 = log(𝑥)
The gradient is very large at D(G(z))=0
Use binary cross entropy loss function with fake label (1)
𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧)[−𝑦 log 𝐷(𝐺 𝑧 ) − 1 − 𝑦 log(1 − 𝐷(𝐺 𝑧 )]
𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧)[− log 𝐷 𝐺 𝑧 ]
𝐺
𝐺
𝑦 = 1
Modification (heuristically motivated)
• Practical Usage](https://image.slidesharecdn.com/generativeadversarialnetworks-170512104624/75/Generative-adversarial-networks-33-2048.jpg)
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- 1. 1 Introduction Generative Adversarial Networks Yunjey Choi KoreaUniversity DAVIAN LAB
- 2. 2 Speaker Introduction Introduction B.S.in Computer Science & Engineering at Korea University M.S. Student in Computer Science & Engineering at Korea University (Current) Interest: Deep Learning,TensorFlow, PyTorch GitHub Link: https://github.com/yunjey
- 3. 3 Referenced Slides Introduction •Namju Kim. Generative Adversarial Networks (GAN) https://www.slideshare.net/ssuser77ee21/generative-adversarial-networks-70896091 • Taehoon Kim. 지적 대화를 위한 깊고 넓은 딥러닝 https://www.slideshare.net/carpedm20/ss-63116251
- 4.
- 5. 5 Branches of MLIntroduction Semi-supervised Learning Unsupervised Learning Supervised Learning Reinforcement Learning Machine Learning No labeled data No feedback “find hidden structure” Labeled data Direct feedback No labeled data Delayed feedback Reward signal
- 6. 6 Supervised Learning Introduction Discriminative Modelwoman The discriminative model learns how to classify input to its class. man (1) (1) (2) (2) Input image (64x64x3)
- 7. 7 Unsupervised Learning Introduction Generative Model Latent code Thegenerative model learns the distribution of training data. (100) Image (64x64x3)
- 8. 8 Generative Model 𝑋 12 3 4 5 6 𝑃 𝑋 1 6 1 6 1 6 0 6 1 6 2 6 1 2 3 4 5 6 1 6 2 6 𝑝 𝑥 𝑥 Probability Distribution Introduction Random variable Probability Basics (Review) Probability mass function
- 9. 9 Generative Model What if𝑥 is actual images in the training data? At this point, 𝑥 can be represented as a (for example) 64x64x3 dimensional vector. Probability Distribution Introduction
- 10. 10 Generative Model 𝑥 𝑝 𝑑𝑎𝑡𝑎(𝑥) ProbabilityDistribution Introduction There is a 𝑝 𝑑𝑎𝑡𝑎(𝑥) that represents the distribution of actual images. Probability density function
- 11. 11 Generative Model 𝑥 𝑝 𝑑𝑎𝑡𝑎(𝑥) ProbabilityDistribution Introduction Let’s take an example with human face image dataset. Our dataset may contain few images of men with glasses. 𝑥1 𝑥2 𝑥3 𝑥4 𝑥1 is a 64x64x3 high dimensional vector representing a man with glasses. The probability density value is low
- 12. The probability density valueis high 12 Generative Model 𝑥 𝑝 𝑑𝑎𝑡𝑎(𝑥) Probability Distribution Introduction Our dataset may contain many images of women with black hair. 𝑥1 𝑥2 𝑥3 𝑥4 𝑥2 is a 64x64x3 high dimensional vector representing a woman with black hair.
- 13. 13 Generative Model 𝑥 𝑝 𝑑𝑎𝑡𝑎(𝑥) ProbabilityDistribution Introduction Our dataset may contain very many images of women with blonde hair. 𝑥1 𝑥2 𝑥3 𝑥4 𝑥3 is a 64x64x3 high dimensional vector representing a woman with blonde hair. The probability density value is very high
- 14. 14 Generative Model 𝑥 𝑝 𝑑𝑎𝑡𝑎(𝑥) ProbabilityDistribution Introduction Our dataset may not contain these strange images. 𝑥1 𝑥2 𝑥3 𝑥4 𝑥4 is an 64x64x3 high dimensional vector representing very strange images. The probability density value is almost 0
- 15. 15 Generative Model 𝑥 Probability DistributionIntroduction The goal of the generative model is to find a 𝑝 𝑚𝑜𝑑𝑒𝑙(𝑥) that approximates 𝑝 𝑑𝑎𝑡𝑎(𝑥) well. 𝑥1 𝑥2 𝑥3 𝑥4 𝑝 𝑚𝑜𝑑𝑒𝑙(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝐷𝑖𝑠𝑡𝑟𝑖𝑏𝑢𝑡𝑖𝑜𝑛 𝑜𝑓 𝑎𝑐𝑡𝑢𝑎𝑙 𝑖𝑚𝑎𝑔𝑒𝑠 𝐷𝑖𝑠𝑡𝑟𝑖𝑏𝑢𝑡𝑖𝑜𝑛 𝑜𝑓 𝑖𝑚𝑎𝑔𝑒𝑠 𝑔𝑒𝑛𝑒𝑟𝑎𝑡𝑒𝑑 𝑏𝑦 𝑡ℎ𝑒 𝑚𝑜𝑑𝑒𝑙
- 16.
- 17. 17 Intuition in GANGANs G(z) DGz D(G(z)) D D(x) x Fake image Real image The probability of that x came from the real data (0~1)Discriminator Generator Latent Code May be high May be low Training with real images Training with fake images
- 18. 18 Intuition in GANGANs G(z) DGz D(G(z)) D D(x) x Real image (64x64x3) This value should be close to 1.Discriminator (Neural Network) The discriminator should classify a real image as real.
- 19. 19 Intuition in GANGANs G(z) Dz D(G(z)) D D(x) x Fake image generated by the generator (64x64x3) Generator This value should be close to 0. The discriminator should classify a fake image as fake.
- 20. 20 Intuition in GANGANs G(z) DGz D(G(z)) D D(x) x Generated image (64x64x3) Generator (Neural Network) Latent Code (100) This value should be close to 1. The generator should create an image that is indistinguishable from real to deceive the discriminator
- 21. 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺(𝑧))) 21 Objective Function of GAN GANs G(z) DGz D(G(z)) D D(x) x 𝐺 𝐷 Training with real images Training with fake images Maximum when 𝐷(𝑥) = 1 Maximum when 𝐷(𝐺(𝑧)) = 0 Sample 𝑥 from real data distribution Sample latent code 𝑧 from Gaussian distribution Train D to classify fake images as fake Train D to classify real images as real 𝐷 should maximize 𝑉(𝐷, 𝐺) Objective function
- 22. 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺(𝑧))) 𝐺 is independent of this part 22 Objective Function of GAN GANs 𝐺 should minimize 𝑉(𝐷, 𝐺) Minimum when 𝐷(𝐺(𝑧)) = 1 G(z) DGz D(G(z)) D D(x) x Train G to deceive D 𝐺 𝐷 Training with real images Training with fake images Objective function
- 23. 23 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x Training with real images Training with fake images
- 24. Define the discriminator inputsize: 784 hidden size: 128 output size: 1 24 PyTorch Implementation GANs G(z) DGz D(G(z)) D D(x)x Discriminator Assume x is MNIST (784 dimension) Output probability(1 dimension)
- 25. 25 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x Generator Define the generator input size: 100 hidden size: 128 output size: 784 Latent code (100 dimension) Generated image (784 dimension)
- 26. 26 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x Binary Cross Entropy Loss (ℎ(𝑥), 𝑦) − 𝑦 log ℎ 𝑥 − (1 − 𝑦) log(1 − ℎ(𝑥))
- 27. 27 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x Optimizer for D and G
- 28. 28 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x x is a tensor of shape (batch_size, 784). z is a tensor of shape (batch_size, 100).
- 29. 29 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x D(x) gets closer to 1. D(G(z)) gets closer to 0 Forward, Backward and Gradient Descent Train the discriminator with real images Train the discriminator with fake images
- 30. 30 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x Forward, Backward and Gradient Descent D(G(z)) gets closer to 1 Train the generator to deceive the discriminator
- 31. 31 PyTorch Implementation GANs G(z)DGz D(G(z)) D D(x)x The complete code can be found here https://github.com/yunjey/pytorch-tutorial
- 32. 32 Objective Function ofGenerator 𝐺 Objective function of G Non-Saturating Game GANs Images created by the generator at the beginning of training 𝑦 = log(1 − 𝑥) The gradient is relatively small at D(G(z))=0 At the beginning of training, the discriminator can clearly classify the generated image as fake because the quality of the image is very low. This means that D(G(z)) is almost zero at early stages of training. 𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 )
- 33. 33 Solution for PoorGradient 𝐺 𝑚𝑎𝑥 𝐸𝑧~𝑝 𝑧(𝑧) log 𝐷(𝐺 𝑧 ) 𝐺 𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) Non-Saturating Game GANs 𝑦 = log(𝑥) The gradient is very large at D(G(z))=0 Use binary cross entropy loss function with fake label (1) 𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧)[−𝑦 log 𝐷(𝐺 𝑧 ) − 1 − 𝑦 log(1 − 𝐷(𝐺 𝑧 )] 𝑚𝑖𝑛 𝐸𝑧~𝑝 𝑧(𝑧)[− log 𝐷 𝐺 𝑧 ] 𝐺 𝐺 𝑦 = 1 Modification (heuristically motivated) • Practical Usage
- 34. 34 Theory in GANGANs 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝑚𝑖𝑛 𝐽𝑆𝐷(𝑝 𝑑𝑎𝑡𝑎||𝑝 𝑔) 𝐺, 𝐷 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉 𝐷, 𝐺 𝐺 𝐷 𝑥 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝐽𝑆𝐷(𝑃||𝑄) = 1 2 𝐾𝐿(𝑃| 𝑀 + 1 2 𝐾𝐿(𝑄| 𝑀 𝑤ℎ𝑒𝑟𝑒 𝑀 = 1 2 (𝑃 + 𝑄) KL Divergence • Why does GANs work? same Please see Appendix for details Because it actually minimizes the distance between the real data distribution and the model distribution. Objective function of GANs Jenson-Shannon divergence
- 35.
- 36. 36 DCGAN Variants of GAN Radfordet al. Unsupervised Representation Learning with Deep Convolutional Generative Adversarial Networks, 2015 • Deep Convolutional GAN(DCGAN), 2015 The authors present a model that is still highly preferred.
- 37. 37 DCGAN Variants of GAN DGzD(G(z)) D D(x) x Use convolution, Leaky ReLU Use deconvolution, ReLU • No pooling layer (Instead strided convolution) • Use batch normalization • Adam optimizer(lr=0.0002, beta1=0.5, beta2=0.999)
- 38. 38 DCGAN Variants of GAN Radfordet al. Unsupervised Representation Learning with Deep Convolutional Generative Adversarial Networks, 2015 • Latent vector arithmetic
- 39. 39 LSGAN Variants of GAN XudongMao et al. Least Squares Generative Adversarial Networks, 2016 • Least Squares GAN (LSGAN) Proposed a GAN model that adopts the least squares loss function for the discriminator.
- 40. 40 LSGAN Variants of GAN VanillaGAN LSGAN Remove sigmoid non-linearity in last layer
- 41. 41 LSGAN Variants of GAN VanillaGAN LSGAN Generator is the same as original
- 42. 42 LSGAN Variants of GAN VanillaGAN LSGAN Replace cross entropy loss to least squares loss (L2) D(x) gets closer to 1 D(G(z)) gets closer to 0 (same as original)
- 43. 43 LSGAN Variants of GAN VanillaGAN LSGAN Replace cross entropy loss to least squares loss (L2) D(G(z)) gets closer to 1 (same as original)
- 44. 44 LSGAN Variants of GAN •Results (LSUN dataset) Xudong Mao et al. Least Squares Generative Adversarial Networks, 2016
- 45. 45 LSGAN Variants of GAN •Results (CelebA)
- 46. 46 SGAN Variants of GAN D GD one-hot vector representing 2 Real image latent vector z fake image (1) FC layer with softmax • Semi-Supervised GAN Training with real images Training with fake images 11 dimension (10 classes + fake) (1) (1) one-hot vector representing a fake label one-hot vector representing 5 Augustus Odena et al. Semi-Supervised Learning with Generative Adversarial Netwoks, 2016
- 47. 47 SGAN Variants of GAN •Results (Game Character) 1 2 3 4 5 The generator can create an character image that takes a certain pose. one-hot vectors representing class labels The code will be available soon: https://github.com/yunjey
- 48. 48 ACGAN Variants of GAN AugustusOdena et al. Conditional Image Synthesis with Auxilary Classifier, 2016 • Auxiliary Classifier GAN(ACGAN), 2016 Proposed a new method for improved training of GANs using class labels.
- 49. 49 ACGAN Variants of GAN realor fake? D G real or fake? D one-hot vector representing 2 Real image one-hot vector representing 5 latent vector z fake image one-hot vector representing 2 (1) FC layer with sigmoid (2) FC layer with softmax (1) (2) Discriminator (multi-task learning) (1) (2) • How does it work? Training with real images Training with fake images
- 50.
- 51. 51 CycleGAN Extensions • CycleGAN:Unpaired Image-to-Image Translation presents a GAN model that transfer an image from a source domain A to a target domain B in the absence of paired examples. Jun-Yan Zhu et al. Unpaired Image-to-Image Translation using Cycle Consistent Adversarial Networks, 2017
- 52. 52 CycleGAN • How doesit work? real or fake ? DB GAB Real Image in domain A Fake Image in domain B Real Image in domain B Discriminator for domain B The generator GAB should generates a horse from the zebra to deceive the discriminator DB. Extensions
- 53. 53 CycleGAN • How doesit work? DB GAB Discriminator for domain B GBA Reconstructed Image L2 Loss GBA generates a reconstructed image of domain A. This makes the shape to be maintained when GAB generates a horse image from the zebra.real or fake ? Real Image in domain A Real Image in domain B Fake Image in domain B Extensions
- 54. 54 CycleGAN Extensions • Results Jun-YanZhu et al. Unpaired Image-to-Image Translation using Cycle Consistent Adversarial Networks, 2017
- 55. 55 CycleGAN Extensions • Results MNIST-to-SVHNSVHN-to-MNIST Oddcolumns contain real images and even columns contain generated images. https://github.com/yunjey/mnist-svhn-transfer
- 56. 56 Text2Image Scott Reed etal. Generative Adversarial Text to Image Synthesis, 2016 • Generative Adversarial Text to Image Synthesis, 2016 presents a novel model architecture that generates an image from the text. Extensions
- 57. 57 Text2Image D Sentence Embedding (100) Is theimage real and relevant to the sentence? Concatenate at last conv layer Discriminator should say ‘yes’. Real image (128x128) • Training with (real image, right text) Extensions “A small red bird with a black beak”
- 58. 58 Text2Image Fake image (128x128) D G Z (100) Sentence Embedding (100) Isthe image real and relevant to the sentence? right text Discriminator should say ‘no’. • Training with (fake image, right text) Generator should creates an image relevant to the sentence to deceive the discriminator. Extensions “A small red bird with a black beak”
- 59. 59 Text2Image D Is theimage real and relevant to the sentence? wrong text (sampled randomly from the training data) Discriminator should say ‘no’. • Training with (real image, wrong text) Extensions Real image (128x128) “A small yellow bird with a brown beak” Sentence Embedding (100)
- 60. 60 StackGAN Han Zhang etal. StackGAN: Text to Photo-realistic Image Synthesis with Stacked Generative Adversarial Networks, 2016 • StackGAN:Text to Photo-realistic Image Synthesis Extensions
- 61. 61 StackGAN Fake image (128x128) Real image (128x128) D G Z (100) ‘real’ or ‘fake’ Generatesa128x128 image from scratch (not guarantee good result) Discriminator for 128x128 image • Generating 128x128 from scratch Extensions
- 62. 62 StackGAN Extensions D1 D2 G1G2 Fake image (64x64) Real image (64x64) Fake image (128x128) Real image (128x128) ‘real’ or ‘fake’ Generates a 64x64 image Upscales a 64x64 image to 128x128 (Easier than generating from scratch). Discriminator for 64x64 image Discriminator for 128x128 image • Generating 128x128 from 64x64 ‘real’ or ‘fake’ Z (100)
- 63.
- 64. 64 Convergence Measure • BoundaryEquilibrium GAN (BEGAN) Extensions David Berthelot et al. BEGAN: Boundary Equilibrium Generative Adversarial Networks, 2017
- 65. 65 Convergence Measure • ReconstructionLoss Extensions Sitao Xiang. On the effect of Batch Normalization and Weight Normalization in Generative Adversarial Network, 2017 Gz G(z) x Test images
- 66. 66 Better Upsampling • DeconvolutionCheckboard Artifacts Extensions http://distill.pub/2016/deconv-checkerboard/
- 67. 67 Better Upsampling • Deconvolutionvs Resize-Convolution Extensions http://distill.pub/2016/deconv-checkerboard/
- 68. 68 GAN in SupervisedLearning • Machine Translation (Seq2Seq) Extensions A B C D Y X Y Z<start> Z <end>X Should ‘ABCD’ be translated to ‘XYZ’? Tackling the supervised learning
- 69. 69 GAN in SupervisedLearning • Machine Translation (GANs) Extensions D G D Training with real sentences Training with fake sentences A (English) B (Korean) Does A and B have the same meaning? The discriminator should say ‘yes’. Does A and B have the same meaning? The discriminator should say ‘no’. A (English) B (Fake Korean) Lijun Wu et al. Adversarial Neural Machine Translation, 2017 The generator should generate B that has the same meaning as A to deceive the discriminator.
- 70.
- 71.
- 72. 72 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐺 𝐷 Theory in GAN GANs 𝑂𝑏𝑗𝑒𝑐𝑡𝑖𝑣𝑒 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐺𝐴𝑁𝑠 𝑟𝑒𝑎𝑙 𝑑𝑎𝑡𝑎 𝑑𝑖𝑠𝑡𝑟𝑖𝑏𝑢𝑡𝑖𝑜𝑛 𝐺𝑎𝑢𝑠𝑠𝑖𝑎𝑛 𝑑𝑖𝑠𝑡𝑟𝑖𝑏𝑢𝑡𝑖𝑜𝑛 ℎ𝑖𝑔ℎ 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛𝑎𝑙 𝑣𝑒𝑐𝑡𝑜𝑟 (𝑒. 𝑔. 64 × 64) l𝑜𝑤 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛𝑎𝑙 𝑣𝑒𝑐𝑡𝑜𝑟 (𝑒. 𝑔. 100)
- 73. 73 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐺 𝐷 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐹𝑖𝑥 𝐺 𝑡𝑜 𝑚𝑎𝑘𝑒 𝑖𝑡 𝑡𝑜 𝑎 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐷 𝑂𝑝𝑡𝑖𝑚𝑎𝑙 𝐷 𝐷 𝐺𝑒𝑡 𝐷 𝑤ℎ𝑒𝑛 𝑉 𝐷 𝑖𝑠 𝑚𝑎𝑥𝑖𝑚𝑢𝑚
- 74. 74 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐺 𝐷 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸 𝑥~𝑝 𝑔(𝑥) log(1 − 𝐷(𝑥)) 𝐹𝑖𝑥 𝐺 𝑡𝑜 𝑚𝑎𝑘𝑒 𝑖𝑡 𝑡𝑜 𝑎 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐷 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑥 𝑓𝑟𝑜𝑚 𝑝 𝑔 𝑖𝑛𝑠𝑡𝑒𝑎𝑑 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑧 𝑓𝑟𝑜𝑚 𝑝𝑧 𝑣𝑒𝑐𝑡𝑜𝑟 𝑜𝑓 64 × 64 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛 𝑣𝑒𝑐𝑡𝑜𝑟 𝑜𝑓 100 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛 𝑚𝑜𝑑𝑒𝑙 𝐺 𝑑𝑖𝑠𝑡𝑟𝑖𝑏𝑢𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 ℎ𝑖𝑔ℎ 𝑑𝑖𝑚𝑒𝑛𝑠𝑖𝑜𝑛𝑎𝑙 𝑣𝑒𝑐𝑡𝑜𝑟 (𝑒. 𝑔. 64 × 64) 𝐷
- 75. 75 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐺 𝐷 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸 𝑥~𝑝 𝑔(𝑥) log(1 − 𝐷(𝑥)) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 𝑑𝑥 𝑥 𝑥 𝐹𝑖𝑥 𝐺 𝑡𝑜 𝑚𝑎𝑘𝑒 𝑖𝑡 𝑡𝑜 𝑎 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐷 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑥 𝑓𝑟𝑜𝑚 𝑝 𝑔 𝑖𝑛𝑠𝑡𝑒𝑎𝑑 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑧 𝑓𝑟𝑜𝑚 𝑝𝑧 = න 𝑝 𝑥 𝑓 𝑥 𝑑𝑥𝐸 𝑥~𝑝(𝑥) 𝑓(𝑥) 𝐷𝑒𝑓𝑖𝑛𝑖𝑡𝑖𝑜𝑛 𝑜𝑓 𝐸𝑥𝑝𝑒𝑐𝑡𝑎𝑡𝑖𝑜𝑛 𝑥 𝐼𝑛𝑡𝑒𝑔𝑟𝑎𝑡𝑒 𝑓𝑜𝑟 𝑎𝑙𝑙 𝑝𝑜𝑠𝑠𝑖𝑏𝑙𝑒 𝑥 𝐷
- 76. 76 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐺 𝐷 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸 𝑥~𝑝 𝑔(𝑥) log(1 − 𝐷(𝑥)) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 𝑑𝑥 = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 𝑑𝑥 𝑥 𝑥 𝑥 𝐹𝑖𝑥 𝐺 𝑡𝑜 𝑚𝑎𝑘𝑒 𝑖𝑡 𝑡𝑜 𝑎 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐷 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑥 𝑓𝑟𝑜𝑚 𝑝 𝑔 𝑖𝑛𝑠𝑡𝑒𝑎𝑑 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑧 𝑓𝑟𝑜𝑚 𝑝𝑧 = න 𝑝 𝑥 𝑓 𝑥 𝑑𝑥𝐸 𝑥~𝑝(𝑥) 𝑓(𝑥) 𝐷𝑒𝑓𝑖𝑛𝑖𝑡𝑖𝑜𝑛 𝑜𝑓 𝐸𝑥𝑝𝑒𝑐𝑡𝑎𝑡𝑖𝑜𝑛 𝑥 𝐵𝑎𝑠𝑖𝑐 𝑝𝑟𝑜𝑝𝑒𝑟𝑡𝑦 𝑜𝑓 𝐼𝑛𝑡𝑒𝑔𝑟𝑎𝑙 𝐷
- 77. 77 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉𝐷, 𝐺 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) 𝐺 𝐷 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸𝑧~𝑝 𝑧(𝑧) log(1 − 𝐷(𝐺 𝑧 ) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎(𝑥) log 𝐷 𝑥 + 𝐸 𝑥~𝑝 𝑔(𝑥) log(1 − 𝐷(𝑥)) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 𝑑𝑥 = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 𝑑𝑥 𝑥 𝑥 𝑥 𝐹𝑖𝑥 𝐺 𝑡𝑜 𝑚𝑎𝑘𝑒 𝑖𝑡 𝑡𝑜 𝑎 𝑓𝑢𝑛𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐷 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑥 𝑓𝑟𝑜𝑚 𝑝 𝑔 𝑖𝑛𝑠𝑡𝑒𝑎𝑑 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑖𝑛𝑔 𝑧 𝑓𝑟𝑜𝑚 𝑝𝑧 = න 𝑝 𝑥 𝑓 𝑥 𝑑𝑥𝐸 𝑥~𝑝(𝑥) 𝑓(𝑥) 𝐷𝑒𝑓𝑖𝑛𝑖𝑡𝑖𝑜𝑛 𝑜𝑓 𝐸𝑥𝑝𝑒𝑐𝑡𝑎𝑡𝑖𝑜𝑛 𝑥 𝐵𝑎𝑠𝑖𝑐 𝑝𝑟𝑜𝑝𝑒𝑟𝑡𝑦 𝑜𝑓 𝐼𝑛𝑡𝑒𝑔𝑟𝑎𝑙 𝑁𝑜𝑤 𝑤𝑒 𝑛𝑒𝑒𝑑 𝑡𝑜 𝑓𝑖𝑛𝑑 𝐷 𝑥 𝑤ℎ𝑖𝑐ℎ 𝑚𝑎𝑘𝑒𝑠 𝑡ℎ𝑒 𝑓𝑢𝑛𝑡𝑖𝑜𝑛 𝑖𝑛𝑠𝑖𝑑𝑒 𝑖𝑛𝑡𝑒𝑔𝑟𝑎𝑙 𝑚𝑎𝑥𝑖𝑚𝑢𝑚. 𝐷
- 78. 78 Theoretical Results = 𝑎𝑟𝑔𝑚𝑎𝑥 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 𝐷 𝐷 𝑇ℎ𝑒 𝑓𝑢𝑛𝑡𝑖𝑜𝑛 𝑖𝑛𝑠𝑖𝑑𝑒 𝑖𝑛𝑡𝑒𝑔𝑟𝑎𝑙
- 79. 79 Theoretical Results = 𝑎𝑟𝑔𝑚𝑎𝑥 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 𝐷 𝐷 𝑎 log 𝑦 + 𝑏 log 1 − 𝑦 𝑆𝑢𝑏𝑠𝑡𝑖𝑡𝑢𝑡𝑒 𝑎 = 𝑝 𝑑𝑎𝑡𝑎 𝑥 , 𝑦 = 𝐷 𝑥 , 𝑏 = 𝑝 𝑔 𝑥
- 80. 80 Theoretical Results = 𝑎𝑟𝑔𝑚𝑎𝑥 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 𝐷 𝐷 𝑎 log 𝑦 + 𝑏 log 1 − 𝑦 𝑎 𝑦 + −𝑏 1 − 𝑦 = 𝑎 − (𝑎 + 𝑏)𝑦 𝑦(1 − 𝑦) 𝑆𝑢𝑏𝑠𝑡𝑖𝑡𝑢𝑡𝑒 𝑎 = 𝑝 𝑑𝑎𝑡𝑎 𝑥 , 𝑦 = 𝐷 𝑥 , 𝑏 = 𝑝 𝑔 𝑥 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑡𝑒 𝑤𝑖𝑡ℎ 𝑟𝑒𝑠𝑝𝑒𝑐𝑡 𝑡𝑜 𝐷 𝑥 𝑢𝑠𝑖𝑛𝑔 𝑁𝑜𝑡𝑒 𝑡ℎ𝑎𝑡 𝐷 𝑥 𝑐𝑎𝑛 𝑛𝑜𝑡 𝑎𝑓𝑓𝑒𝑐𝑡 𝑡𝑜 𝑝 𝑑𝑎𝑡𝑎 𝑥 𝑎𝑛𝑑 𝑝 𝑔 𝑥 . 𝑑 𝑑𝑥 log 𝑓(𝑥) = 𝑓′ (𝑥) 𝑓(𝑥)
- 81. 81 Theoretical Results = 𝑎𝑟𝑔𝑚𝑎𝑥 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 𝐷 𝐷 𝑎 log 𝑦 + 𝑏 log 1 − 𝑦 𝑎 𝑦 + −𝑏 1 − 𝑦 𝑎 − (𝑎 + 𝑏)𝑦 𝑦(1 − 𝑦) = 0 𝑦 = 𝑎 𝑎 + 𝑏 = 𝑎 − (𝑎 + 𝑏)𝑦 𝑦(1 − 𝑦) 𝑆𝑢𝑏𝑠𝑡𝑖𝑡𝑢𝑡𝑒 𝑎 = 𝑝 𝑑𝑎𝑡𝑎 𝑥 , 𝑦 = 𝐷 𝑥 , 𝑏 = 𝑝 𝑔 𝑥 𝑁𝑜𝑡𝑒 𝑡ℎ𝑎𝑡 𝐷 𝑥 𝑐𝑎𝑛 𝑛𝑜𝑡 𝑎𝑓𝑓𝑒𝑐𝑡 𝑡𝑜 𝑝 𝑑𝑎𝑡𝑎 𝑥 𝑎𝑛𝑑 𝑝 𝑔 𝑥 . 𝐼𝑡 ℎ𝑎𝑠 𝑎 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑣𝑎𝑙𝑢𝑒 𝑤ℎ𝑒𝑛 𝑁𝑜𝑡𝑒 𝑡ℎ𝑎𝑡 𝑡ℎ𝑒 𝑙𝑜𝑐𝑎𝑙 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑖𝑠 𝑡ℎ𝑒 𝑔𝑙𝑜𝑏𝑎𝑙 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑤ℎ𝑒𝑛 𝑡ℎ𝑒𝑟𝑒 𝑎𝑟𝑒 𝑛𝑜 𝑜𝑡ℎ𝑒𝑟 𝑙𝑜𝑐𝑎𝑙 𝑒𝑥𝑡𝑟𝑒𝑚𝑒𝑠. 𝑑 𝑑𝑥 log 𝑓(𝑥) = 𝑓′ (𝑥) 𝑓(𝑥) 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑡𝑒 𝑤𝑖𝑡ℎ 𝑟𝑒𝑠𝑝𝑒𝑐𝑡 𝑡𝑜 𝐷 𝑥 𝑢𝑠𝑖𝑛𝑔 𝐹𝑖𝑛𝑑 𝑡ℎ𝑒 𝑝𝑜𝑖𝑛𝑡 𝑤ℎ𝑒𝑟𝑒 𝑡ℎ𝑒 𝑑𝑒𝑟𝑖𝑣𝑎𝑡𝑖𝑣𝑒 𝑣𝑎𝑙𝑢𝑒 𝑖𝑠 0 𝑙𝑜𝑐𝑎𝑙 𝑒𝑥𝑡𝑟𝑒𝑚𝑒 .
- 82. 82 Theoretical Results = 𝑎𝑟𝑔𝑚𝑎𝑥 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝐷 𝑥 + 𝑝 𝑔 𝑥 log 1 − 𝐷 𝑥 Theory in GAN GANs 𝐷∗(𝑥) = 𝑎𝑟𝑔 𝑚𝑎𝑥 𝑉 𝐷 𝐷 𝐷 𝑎 log 𝑦 + 𝑏 log 1 − 𝑦 𝑎 𝑦 + −𝑏 1 − 𝑦 𝑎 − (𝑎 + 𝑏)𝑦 𝑦(1 − 𝑦) = 0 𝑦 = 𝑎 𝑎 + 𝑏 = 𝑎 − (𝑎 + 𝑏)𝑦 𝑦(1 − 𝑦) 𝑆𝑢𝑏𝑠𝑡𝑖𝑡𝑢𝑡𝑒 𝑎 = 𝑝 𝑑𝑎𝑡𝑎 𝑥 , 𝑦 = 𝐷 𝑥 , 𝑏 = 𝑝 𝑔 𝑥 𝑁𝑜𝑡𝑒 𝑡ℎ𝑎𝑡 𝐷 𝑥 𝑐𝑎𝑛 𝑛𝑜𝑡 𝑎𝑓𝑓𝑒𝑐𝑡 𝑡𝑜 𝑝 𝑑𝑎𝑡𝑎 𝑥 𝑎𝑛𝑑 𝑝 𝑔 𝑥 . 𝐼𝑡 ℎ𝑎𝑠 𝑎 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑣𝑎𝑙𝑢𝑒 𝑤ℎ𝑒𝑛 𝑑 𝑑𝑥 log 𝑓(𝑥) = 𝑓′ (𝑥) 𝑓(𝑥) 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡𝑖𝑎𝑡𝑒 𝑤𝑖𝑡ℎ 𝑟𝑒𝑠𝑝𝑒𝑐𝑡 𝑡𝑜 𝐷 𝑥 𝑢𝑠𝑖𝑛𝑔 𝐹𝑖𝑛𝑑 𝑡ℎ𝑒 𝑝𝑜𝑖𝑛𝑡 𝑤ℎ𝑒𝑟𝑒 𝑡ℎ𝑒 𝑑𝑒𝑟𝑖𝑣𝑎𝑡𝑖𝑣𝑒 𝑣𝑎𝑙𝑢𝑒 𝑖𝑠 0 𝑙𝑜𝑐𝑎𝑙 𝑒𝑥𝑡𝑟𝑒𝑚𝑒 . 𝐷∗ 𝑥 = 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑆𝑢𝑏𝑠𝑡𝑖𝑡𝑢𝑡𝑒 𝑎 = 𝑝 𝑑𝑎𝑡𝑎 𝑥 , 𝑦 = 𝐷 𝑥 , 𝑏 = 𝑝 𝑔 𝑥
- 83. 83 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 Objective Function of G (G should minimize C(G) Theory in GAN GANs
- 84. 84 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) Theory in GAN GANs Optimal discriminator
- 85. 85 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) Theory in GAN GANs
- 86. 86 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥 = න 𝑝 𝑥 𝑓 𝑥 𝑑𝑥𝐸 𝑥~𝑝(𝑥) 𝑓(𝑥) Definition of Expectation 𝑥
- 87. 87 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥
- 88. 88 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥 𝑥 𝑥 How?
- 89. 89 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 න 𝑝 𝑑𝑎𝑡𝑎 𝑥 𝑑𝑥 = 1 Theory in GAN GANs 𝑥 Property of probability density function
- 90. 90 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 න 𝑝 𝑑𝑎𝑡𝑎 𝑥 𝑑𝑥 = 1 𝑙𝑜𝑔2 = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 ∙ 𝑙𝑜𝑔2 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥trick
- 91. 91 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 න 𝑝 𝑑𝑎𝑡𝑎 𝑥 𝑑𝑥 = 1 𝑙𝑜𝑔2 = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 ∙ 𝑙𝑜𝑔2 𝑑𝑥 𝑙𝑜𝑔2 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥 𝑥 𝑥
- 92. 92 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥 𝑥𝑥
- 93. 93 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) Theory in GAN GANs 𝑥𝑥
- 94. 94 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) 𝐾𝐿(𝑃| 𝑄 = න 𝑃(𝑥) log 𝑃(𝑥) 𝑄(𝑥) 𝑑𝑥 Theory in GAN GANs 𝑥 𝑥 𝑥 Definition of KL-Divergence
- 95. 95 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) 𝐾𝐿(𝑃| 𝑄 = න 𝑃(𝑥) log 𝑃(𝑥) 𝑄(𝑥) 𝑑𝑥 න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 2 𝑑𝑥 = 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) Theory in GAN GANs 𝑥 𝑥 𝑥 𝑥
- 96. 96 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) = −𝑙𝑜𝑔4 + 2 ∙ 𝐽𝑆𝐷(𝑝 𝑑𝑎𝑡𝑎||𝑝 𝑔) Theory in GAN GANs
- 97. 97 Theoretical Results 𝐶 𝐺= max 𝑉(𝐷, 𝐺) 𝐷 = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗(𝑥)) = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) + 𝐸 𝑥~𝑝 𝑔 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) = −𝑙𝑜𝑔4 + 2 ∙ 𝐽𝑆𝐷(𝑝 𝑑𝑎𝑡𝑎||𝑝 𝑔) Theory in GAN GANs
- 98. 98 Theory in GANGANs = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗ (𝑥)) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) = −𝑙𝑜𝑔4 + 2 ∙ 𝐽𝑆𝐷(𝑝 𝑑𝑎𝑡𝑎||𝑝 𝑔) 𝑥 𝑥 𝑥 𝑥 𝑥𝑥 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉 𝐷, 𝐺 = 𝐺 𝐷 𝑚𝑖𝑛 𝑉 𝐷∗, 𝐺 𝐺 𝑉 𝐷∗, 𝐺
- 99. 99 Theory in GANGANs = 𝐸 𝑥~𝑝 𝑑𝑎𝑡𝑎 log 𝐷∗ 𝑥 + 𝐸 𝑥~𝑝 𝑔 log(1 − 𝐷∗ (𝑥)) = න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + න 𝑝 𝑑𝑎𝑡𝑎 𝑥 log 2 ∙ 𝑝 𝑑𝑎𝑡𝑎(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 + න 𝑝 𝑔 𝑥 log 2 ∙ 𝑝 𝑔(𝑥) 𝑝 𝑑𝑎𝑡𝑎(𝑥) + 𝑝 𝑔(𝑥) 𝑑𝑥 = −𝑙𝑜𝑔4 + 𝐾𝐿(𝑝 𝑑𝑎𝑡𝑎|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) + 𝐾𝐿(𝑝 𝑔|| 𝑝 𝑑𝑎𝑡𝑎 + 𝑝 𝑔 2 ) = −𝑙𝑜𝑔4 + 2 ∙ 𝐽𝑆𝐷(𝑝 𝑑𝑎𝑡𝑎||𝑝 𝑔) 𝑥 𝑥 𝑥 𝑥 𝑥𝑥 𝑚𝑖𝑛 𝑚𝑎𝑥 𝑉 𝐷, 𝐺 = 𝐺 𝐷 𝑚𝑖𝑛 𝑉 𝐷∗, 𝐺 𝐺 𝑉 𝐷∗, 𝐺 𝐺 𝑠ℎ𝑜𝑢𝑙𝑑 𝑚𝑖𝑛𝑖𝑚𝑖𝑧𝑒 𝐺 𝑠ℎ𝑜𝑢𝑙𝑑 𝑚𝑖𝑛𝑖𝑚𝑖𝑧𝑒 𝑂𝑝𝑡𝑖𝑚𝑖𝑧𝑖𝑛𝑔 𝑉 𝐷, 𝐺 𝑖𝑠 𝑠𝑎𝑚𝑒 𝑎𝑠 𝑚𝑖𝑛𝑖𝑚𝑖𝑧𝑖𝑛𝑔 𝐽𝑆𝐷(𝑝 𝑑𝑎𝑡𝑎||𝑝 𝑔) 𝑂𝑝𝑡𝑖𝑚𝑎𝑙 𝐷