The Modern Mathematics of Deep Learning

A changing output

Penguin learning project

The project uses 342 complete Palmer penguin records: 240 training-pool and 102 held-out rows. The selected training rows determine feature scaling and model parameters. Source CSV

This project trains weights with softmax, unlike the homepage lab, which uses nearest species averages. Same penguin measurements; different classification methods. Predictions can differ.

Classification predicts three species; Ridge predicts body mass in grams using the same observations. These are separate models. Training predictions feed the objective; 102 separate test predictions never update the weights.

Functions and derivatives · Describe maps and how their outputs change.

Project vectors have two features; the training matrix has n rows and two columns. Mathematical tools may operate on these values when their assumptions apply.

TaskTraining rowsTraining stepsPenalty αHeld-out row ID

Project operation

Output: ≈0.004056

Project operation

The project calculation uses these records; the source formula and example follow below. Code edits run locally; project settings travel between pages.

Objective → Project operation → Project operation

Project input

Showing first three entries; the operation receives the complete array. Rounded preview; the operation uses full precision.

input.features · Features: [[≈-1.946, ≈-1.283], [≈-0.6098, ≈-1.029], [≈-0.4454, ≈0.9162]] … (12 entries)
input.targets · Observations: [0, 1, 2] … (12 entries)
input.weights · Model: [≈-0.2895, ≈-2.052, ≈-1.016] … (9 entries)
input.alpha · Project settings or constant: 0.001
input.task · Project settings or constant: classification
input.epsilon · Project settings or constant: 0.0001

JavaScript

Result

≈0.004056

Teaching example; no specific paper passage attached.

This quotient compares two nearby outputs. For f(x)=x², it approaches the derivative 2x as nonzero h approaches zero.

Derivatives describe how an output changes with an input.

Source formula example

\frac{f(x+h)-f(x)}{h}

approximation · The finite difference is not the derivative unless the chosen function and step happen to give the same value. Very small steps can amplify rounding error.

Source formula example

This source example uses its own inputs and assumptions. Editing it does not change the project.

Edit a value or the code, then run the example. This is a finite demonstration, not a proof of the paper’s theorem.

xStep h

This example’s data flow

You choose

input.x = 2
input.h = 0.1

Calculated here

Result expression: { slope, derivative: 2 * x }

x = input.x Uses: input.x
h = input.h Uses: input.h
slope = ((x + h) ** 2 - x ** 2) / h Uses: x, h

Returns

Example result

slope: 4.1
derivative: 4

JavaScript

Read numbers from input and return the result. JavaScript basics.

Result

Enable JavaScript to run this example.

Technical statement

Change the input and run the same code again. The displayed result uses the values shown above.

Source: Teaching example