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@dwilliamson
dwilliamson / Adjacency.cpp
Last active February 26, 2023 10:34
Simple, fast adjacency builder
struct Adjacency
{
struct Vertex
{
// Vertices are shared by a variable number of edges. This indexes the global EdgeRef array.
uint32_t edgeStartRef;
uint32_t nbEdges;
};
union EdgeRef
// --- Library --------------------------------------------------------------------------
#include <string.h>
#include <assert.h>
struct ui_box {int x,y,w,h;};
typedef unsigned long long ui_id;
struct ui_node {
int parent;
int lst, end, nxt;
int siz[2];
import numpy as np
def plu_inplace(A):
P = np.arange(len(A))
for i in range(len(A)):
j = i + np.argmax(np.abs(A[i:, i]))
P[[i, j]], A[[i, j]] = P[[j, i]], A[[j, i]]
A[i+1:, i] /= A[i, i]
A[i+1:, i+1:] -= np.outer(A[i+1:, i], A[i, i+1:])
return P, A, A
# Tensor product contractions with Einstein's summation notation. Examples:
# Matrix-matrix multiply is tensor(A, 'ij', B, 'jk')
# Matrix-vector multiply is tensor(A, 'ij', v, 'j')
# Matrix trace is tensor(A, 'ii')
# Matrix transpose is tensor(A, 'ji')
# Matrix diagonal is tensor('i', A, 'ii')
# Inner product is tensor(v, 'i', w, 'i')
# Outer product is tensor(v, 'i', w, 'j')
def tensor(*args, **kwargs):
result = ''

Multi-dimensional array views for systems programmers

As C programmers, most of us think of pointer arithmetic for multi-dimensional arrays in a nested way:

The address for a 1-dimensional array is base + x. The address for a 2-dimensional array is base + x + y*x_size for row-major layout and base + y + x*y_size for column-major layout. The address for a 3-dimensional array is base + x + (y + z*y_size)*x_size for row-column-major layout. And so on.

@d7samurai
d7samurai / .readme.md
Last active September 21, 2024 13:45
Minimal D3D11

Minimal D3D11

Minimal D3D11 reference implementation: An uncluttered Direct3D 11 setup + basic rendering primer and API familiarizer. Complete, runnable Windows application contained in a single function and laid out in a linear, step-by-step fashion that should be easy to follow from the code alone. ~200 LOC. No modern C++, OOP or (other) obscuring cruft. View on YouTube

hollowcube

Also check out Minimal D3D11 pt2, reconfigured for instanced rendering and with a smaller, tighter, simplified overall code structure, or Minimal D3D11 pt3, with shadowmapping + showcasing a range of alternative setup and rendering techniques.

@rxwei
rxwei / ad-manifesto.md
Last active November 9, 2023 09:58
First-Class Automatic Differentiation in Swift: A Manifesto
@jcowles
jcowles / MachineLearningResources.md
Last active November 9, 2023 09:56
Machine learning resources

"AI is the new Electricity"

Andrew Ng lecture, Stanford Graduate School of Business
High level, but totally worth watching.
https://www.youtube.com/watch?v=21EiKfQYZXc

Stanford cs231n, winter 2016

I went looking for lectures from different sources and these are a great "from first principles" introduction. The newer cs231n lectures may have more relevant details, but I like Andrej Karpathy's

//
// Author: Jonathan Blow
// Version: 1
// Date: 31 August, 2018
//
// This code is released under the MIT license, which you can find at
//
// https://opensource.org/licenses/MIT
//
//
//
// TinyCRT, revamp and TinyWin support by Don Williamson, 2011
// Based on http://www.codeproject.com/KB/library/tlibc.aspx and LIBCTINY by Matt Pietrek
//
#pragma once
#ifdef USE_DEFAULT_CRT