|
| 1 | +--- |
| 2 | +title: 'Introduction to Generative Models' |
| 3 | +description: 'Introduction to Generative Models' |
| 4 | +pubDate: '2025-09-11' |
| 5 | +heroImage: '../../assets/blog-placeholder-3.jpg' |
| 6 | +--- |
| 7 | + |
| 8 | +import T from '../../components/TypstMath.astro' |
| 9 | + |
| 10 | +This Lecture is an general introduction to generative modelling. |
| 11 | + |
| 12 | +### Introduction |
| 13 | + |
| 14 | +This is an introduction to the main settings encountered in generative modelling. The first Lectures will introduce the main algorithms and concept for the vanilla unconditional generative modelling task. |
| 15 | +At the end of the course, we will make excursions to class-conditional and text-conditional generative modelling. |
| 16 | + |
| 17 | + |
| 18 | +#### Unconditional Generative Modelling |
| 19 | + |
| 20 | +**What** In *unconditional* generative modelling, we are given a set of unlabelled data |
| 21 | + |
| 22 | +<T block v='text("Data: ") underbrace({x_1, x_2, x_3,dots, x_n}, n "observations") in bb(R)^d .' /> |
| 23 | + |
| 24 | + |
| 25 | +export const catGallery = [ |
| 26 | + { |
| 27 | + url: "https://images.pexels.com/photos/57416/cat-sweet-kitty-animals-57416.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 28 | + caption: "x1", |
| 29 | + alt: "Cute cat 1" |
| 30 | + }, |
| 31 | + { |
| 32 | + url: "https://images.pexels.com/photos/20787/pexels-photo.jpg?auto=compress&cs=tinysrgb&w=800", |
| 33 | + caption: "x2", |
| 34 | + alt: "Cute cat 2" |
| 35 | + }, |
| 36 | + { |
| 37 | + url: "https://images.pexels.com/photos/1183434/pexels-photo-1183434.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 38 | + caption: "x3", |
| 39 | + alt: "Cute cat 3" |
| 40 | + }, |
| 41 | + { |
| 42 | + url: "https://images.pexels.com/photos/979247/pexels-photo-979247.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 43 | + caption: "x4", |
| 44 | + alt: "Cute cat 4" |
| 45 | + }, |
| 46 | + { |
| 47 | + url: "https://images.pexels.com/photos/2558605/pexels-photo-2558605.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 48 | + caption: "x5", |
| 49 | + alt: "Cute cat 5" |
| 50 | + }, |
| 51 | + { |
| 52 | + url: "https://images.pexels.com/photos/1276553/pexels-photo-1276553.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 53 | + caption: "x6", |
| 54 | + alt: "Cute cat 5" |
| 55 | + } |
| 56 | +] |
| 57 | + |
| 58 | +<figure> |
| 59 | + <div style={{ |
| 60 | + display: "grid", |
| 61 | + gridTemplateColumns: "repeat(auto-fit, minmax(200px, 1fr))", |
| 62 | + gap: "1rem", |
| 63 | + alignItems: "start" |
| 64 | + }}> |
| 65 | + {catGallery.map((cat, idx) => ( |
| 66 | + <figure key={idx} style={{ margin: 0 }}> {/* remove default margin */} |
| 67 | + <img |
| 68 | + src={cat.url} |
| 69 | + alt={cat.alt} |
| 70 | + style={{ width: "100%", height: "auto", objectFit: "cover", display: "block" }} |
| 71 | + /> |
| 72 | + <figcaption style={{ |
| 73 | + textAlign: "center", |
| 74 | + fontSize: "0.85rem", |
| 75 | + color: "#6b7280", |
| 76 | + margin: 0, // remove figcaption margin |
| 77 | + marginTop: "0.25rem" // optional small spacing |
| 78 | + }}> |
| 79 | + {cat.caption} |
| 80 | + </figcaption> |
| 81 | + </figure> |
| 82 | + ))} |
| 83 | + </div> |
| 84 | + |
| 85 | + <figcaption style={{ |
| 86 | + textAlign: "center", |
| 87 | + marginTop: "1rem", |
| 88 | + fontStyle: "italic", |
| 89 | + color: "#6b7280" |
| 90 | + }}> |
| 91 | + A dataset of cat photos (source, Pexels.com). |
| 92 | + </figcaption> |
| 93 | +</figure> |
| 94 | + |
| 95 | +**Assumption** The core underlying assumption of generative modelling is that the data $x_1, \dots, x_n$, is drawn from some *unknown* underlying distribution $p_{data}$: for all $i \in 1, \dots, n$ |
| 96 | + |
| 97 | +<T block v='x_i ~ underbrace(p_"data", "unknown") .' /> |
| 98 | + |
| 99 | +**Goal** Using the empirical data distribution $x_1, \dots, x_n \sim p_{data}$, the goal is to *generate* new samples $x^{\text{new}}$ that look like they were drawn from the same *unknown* distribution $p_{data}$ |
| 100 | + |
| 101 | + |
| 102 | +<T block v='x^"new" ~ p_"data" .' /> |
| 103 | + |
| 104 | + |
| 105 | +#### Class-Conditional Generative Modelling |
| 106 | + |
| 107 | +**What** In *class-conditional* generative modelling, we are given a set of labelled data |
| 108 | + |
| 109 | +<T block v='text("Data: ") underbrace({(x_1, y_1),dots, (x_n, y_n)}, n "labelled observations") in bb(R)^d times bb(R) .' /> |
| 110 | + |
| 111 | + |
| 112 | +export const catDogGallery = [ |
| 113 | + { |
| 114 | + url: "https://images.pexels.com/photos/57416/cat-sweet-kitty-animals-57416.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 115 | + caption: "x1, y1=cat", |
| 116 | + alt: "Cute cat 1" |
| 117 | + }, |
| 118 | + { |
| 119 | + url: "https://images.pexels.com/photos/20787/pexels-photo.jpg?auto=compress&cs=tinysrgb&w=800", |
| 120 | + caption: "x2, y2=cat", |
| 121 | + alt: "Cute cat 2" |
| 122 | + }, |
| 123 | + { |
| 124 | + url: "https://images.pexels.com/photos/1183434/pexels-photo-1183434.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 125 | + caption: "x3, y3=cat", |
| 126 | + alt: "Cute cat 3" |
| 127 | + }, |
| 128 | + { |
| 129 | + url: "https://images.pexels.com/photos/58997/pexels-photo-58997.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 130 | + caption: "x4, y4=dog", |
| 131 | + alt: "Cute cat 4" |
| 132 | + }, |
| 133 | + { |
| 134 | + url: "https://images.pexels.com/photos/731022/pexels-photo-731022.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 135 | + caption: "x5, y5=dog", |
| 136 | + alt: "Cute cat 5" |
| 137 | + }, |
| 138 | + { |
| 139 | + url: "https://images.pexels.com/photos/551628/pexels-photo-551628.jpeg?auto=compress&cs=tinysrgb&w=800", |
| 140 | + caption: "x6, y6=dog", |
| 141 | + alt: "Cute cat 5" |
| 142 | + } |
| 143 | +] |
| 144 | + |
| 145 | +<figure> |
| 146 | + <div style={{ |
| 147 | + display: "grid", |
| 148 | + gridTemplateColumns: "repeat(auto-fit, minmax(200px, 1fr))", |
| 149 | + gap: "1rem", |
| 150 | + alignItems: "start" |
| 151 | + }}> |
| 152 | + {catDogGallery.map((cat, idx) => ( |
| 153 | + <figure key={idx} style={{ margin: 0 }}> {/* remove default margin */} |
| 154 | + <img |
| 155 | + src={cat.url} |
| 156 | + alt={cat.alt} |
| 157 | + style={{ width: "100%", height: "auto", objectFit: "cover", display: "block" }} |
| 158 | + /> |
| 159 | + <figcaption style={{ |
| 160 | + textAlign: "center", |
| 161 | + fontSize: "0.85rem", |
| 162 | + color: "#6b7280", |
| 163 | + margin: 0, // remove figcaption margin |
| 164 | + marginTop: "0.25rem" // optional small spacing |
| 165 | + }}> |
| 166 | + {cat.caption} |
| 167 | + </figcaption> |
| 168 | + </figure> |
| 169 | + ))} |
| 170 | + </div> |
| 171 | + |
| 172 | + <figcaption style={{ |
| 173 | + textAlign: "center", |
| 174 | + marginTop: "1rem", |
| 175 | + fontStyle: "italic", |
| 176 | + color: "#6b7280" |
| 177 | + }}> |
| 178 | + A labelled dataset of cat and dog photos (source, Pexels.com). |
| 179 | + </figcaption> |
| 180 | +</figure> |
| 181 | + |
| 182 | + |
| 183 | +**Assumption** The core underlying assumption of generative modelling is that the data $x_1, \dots, x_n$, is drawn from some *unknown* underlying distribution $p_{data}( \cdot | y_i)$: for all $i \in 1, \dots, n$ |
| 184 | + |
| 185 | +<T block v='x_i ~ underbrace(p_"data" (dot | y_i), "unknown") .' /> |
| 186 | + |
| 187 | +**Goal** Using the empirical data distribution $x_i \sim p_{data}(\cdot | y_i)$, the goal is to *generate* new samples $x^{\text{new}}$ that look like they were drawn from the same *unknown* distribution $p_{data}$ |
| 188 | + |
| 189 | + |
| 190 | +<T block v='x^"new cat" ~ p_"data" (dot | y="cat") ,' /> |
| 191 | +<T block v='x^"new dog" ~ p_"data" (dot | y="dog") .' /> |
| 192 | + |
| 193 | +#### Text-Conditional Generative Modelling |
| 194 | + |
| 195 | +### Unconditional Generative Modelling |
| 196 | + |
| 197 | +#### 1 and 2-Dimensional Examples |
| 198 | + |
| 199 | +#### Maximum Likelihood |
| 200 | + |
| 201 | +### References |
| 202 | +- https://people.cs.umass.edu/~domke/courses/sml/10probabilistic.pdf |
| 203 | +- https://people.cs.umass.edu/~domke/courses/sml/11em.pdf |
0 commit comments