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@karpathy
karpathy / pg-pong.py
Created May 30, 2016 22:50
Training a Neural Network ATARI Pong agent with Policy Gradients from raw pixels
""" Trains an agent with (stochastic) Policy Gradients on Pong. Uses OpenAI Gym. """
import numpy as np
import cPickle as pickle
import gym
# hyperparameters
H = 200 # number of hidden layer neurons
batch_size = 10 # every how many episodes to do a param update?
learning_rate = 1e-4
gamma = 0.99 # discount factor for reward

I've come up with an interesting design for a hash map that instead of bucket lists, recursivly embeds more hash maps, but with a new key for each level.

Each hash map is super simple with two slots and hashe keys are 1 bit. However, the initial value is hashed to a 32-bit integer where each bit in the number is the key for each level in the recursive hash map.

In C, my structure looks like:

struct hash_tree_node {
  void *key;
 void *value;
@christopher-hopper
christopher-hopper / clone-mysql-db.sh
Last active January 15, 2021 17:16
Clone a MySQL database to a new database on the same server without using a dump file. This is much faster than using mysqldump.
#!/bin/bash
DBUSER="root";
DBPASS="";
DBHOST="localhost";
DB_OLD=mydatabase
DB_NEW=clone_mydatabase
DBCONN="--host=${DBHOST} --user=${DBUSER} --password=${DBPASS}";