README.md

número

A friendly and intuitive math library for p5.js

This p5.js addon library provides a beginner-friendly Tensor class that's similar to a NumPy array. It builds on the linear algebra engine from TensorFlow.js and adapts it for sketching. You can view número's source code along with examples on GitHub.

Usage

número's Tensor class is a generalization of numbers (scalars), vectors, and matrices. Tensors are used heavily in fields ranging from physics to machine learning. Here are a few examples of Tensors you may recognize:

// The age of a cat in years.
// Rank-0 (Scalar)
let age = createTensor(5);

// The position of a cat in space.
// Rank-1 (Vector)
let position = createTensor([10, 20, 30]);

// The grayscale values of the pixels in a 2x2 cat picture.
// Rank-2 (Matrix)
let grayscale = createTensor([[100, 187],
                              [123, 182]]);

// The RGB values of the pixels in a 2x2 cat picture.
// Rank-3 (Array of Matrices)
let rgb = createTensor([
                        // Red.
                        [[100, 187],
                        [123, 182]],
                        // Green.
                        [[80, 205],
                        [20, 133]],
                        // Blue.
                        [[201, 72],
                        [209, 247]],
                      ]);

The following example multiplies a rank-1 Tensor (vector) by a rank-2 Tensor (matrix):

function setup() {
  createCanvas(400, 400);

  background(220);

  // Translate the origin to the center.
  translate(200, 200);
  
  // Create the rotation matrix.
  let R = createTensor([[cos(HALF_PI), -sin(HALF_PI)],
                        [sin(HALF_PI), cos(HALF_PI)]]);

  // Create the vector.
  let v = createTensor([100, 0]);

  // Get the vector's components.
  let [x1, y1] = v.arraySync();

  // Draw the vector in red.
  stroke('red');
  line(0, 0, x1, y1);

  // Rotate the vector using matrix-vector multiplication,
  // also called the "inner" or "dot" product.
  v = R.dot(v);

  // Get the rotated vector's components.
  let [x2, y2] = v.arraySync();

  // Draw the rotated vector in blue.
  stroke('blue');
  line(0, 0, x2, y2);

  describe('Two lines extend from the center of a gray square. A red line extends to the right. A blue line extends downward.');
}

Contributing

See CONTRIBUTING.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

Ashneel Das 💻 ⚠️

This project follows the all-contributors specification. Contributions of any kind welcome!