Yaseen ynx0

quick recap on complex numbers

Take a number, square it, the result is non-negative. Because positive * positive = positive and negative * negative is positive. Or $0^2 = 0^2$.

But someone wanted to take square roots of negative numbers, so they did, and called it 'i'. $\sqrt{-1} = i$. A lot of people were frustrated upon learning this "You can't do that!", "How do you know that it doesn't lead to contradictions".

The solution, to put imaginary and complex numbers on a solid foundation is something called a ring quotient. What you do is you start with the ring (meaning number system) of polynomials over the real numbers $R[i]$, which looks like this:

$1, 2 3.5, \pi$ etc.
$i, i^2, 0.3 + 9.5 i + 23 i^3$ and so on.

Vagrant and VMWare Tech Preview 21H1 on Apple M1 Pro

UPDATE November 20, 2022: VMWare Fusion 13

VMWare Fusion 13 is now released. Read Vagrant and VMWare Fusion 13 Player on Apple M1 Pro for the latest.

Summary

This document summarizes notes taken while to make the VMWare Tech preview work on Apple M1 Pro, it originated

Ames Push-Based Reconnect

As it stands, Ames re-sends packets to an offline peer forever, every two minutes. For a ship with, say, 2400 offline subscribers to five chat channels, this adds up to a hundred packets being sent per second to ships that aren't there. A lot of those packets will also go through a relay before being hurled into the void, forcing the relay to do essentially meaningless work.

This is a fair amount of wasted CPU, bandwidth, and disk usage (every retry is a new Arvo event on the sender, which must be written to disk). To make it worse, the retry rate trades off against reconnect latency. If my ship comes back online after a few minutes of downtime, it will take on average one minute -- half the retry interval -- before I hear retried packets from my peers. Lowering the retry interval to lessen the reconnect time would increase the bunk packet rate, which increases systemic load on the network.

A couple years ago, ~wicdev-wisryt proposed switching Ames to use push-based recon

Remote Scry Protocol Proposal

Overview

Despite Urbit's "scry" namespace being global (every request path contains the host ship), there is no way to query other ships. This proposal adds a second Urbit-to-Urbit network protocol that implements remote scrying. This will allow for ships to field read requests without incurring disk writes, and since the namespace is immutable, caching responses will be simple and worthwhile.

To "scry" in Urbit means to query the Urbit namespace. Conceptually, if a query resolves, it can produce either a piece of marked data (meaning tagged with a system-recognized type) or an empty result indicating that this path will never contain data. Not all requests resolve; some "block", which represents a refusal or inability to answer the question (such as a local query for a file at a future date). The namespace is immutable in the sense that all nonblocking results to the same query must be identical. Whether a query resolves is not specified; a query could succeed, the

It's useful to have standard names for types, but it's also useful to have standard names for variables. In Hoon, we strive for unambigious and fast pronounceability. If you read a Hoon program to me over the phone, I should be able to dictate it perfectly without wondering how something is spelled. While this goal is probably not completely achievable, we can get a lot closer than we are right now. I propose a scheme for getting close to this.

In many programming languages, single-letter variable names are common. In Hoon, these are called "ultra-lapidary style". These usually satisfy Hoon's pronunciation requirement, but they do not map naturally onto meaningful concepts except when the number of variables is very low. For a comparator function, taking in 'a' and 'b' is fine. But for arguments whose meaning is more semantic than positional, which is most of the time, a name should have some mnemonic connection to the value it signifies.

The natural way to do this is a full word, which should be c

This now exists on urbit.org here

So you want to modify the text of a PDF by hand...

If you, like me, resent every dollar spent on commercial PDF tools, you might want to know how to change the text content of a PDF without having to pay for Adobe Acrobat or another PDF tool. I didn't see an obvious open-source tool that lets you dig into PDF internals, but I did discover a few useful facts about how PDFs are structured that I think may prove useful to others (or myself) in the future. They are recorded here. They are surely not universally applicable --
the PDF standard is truly Byzantine -- but they worked for my case.

	#!/usr/bin/env python3
	import fileinput
	import re

	def main():
	for line in fileinput.input():
	if not re.search(r'^[0-9a-fA-F]+$', line):
	continue
	print('0x', end='')
	line = line.strip().lstrip('0')

	#!/usr/bin/env python3

	def cli():

	@command
	def hello(*args):
	cmd('echo', 'Hello', *args)

	\|%
	+$ resource [=ship =term] :: A resource is a ship and a term.
	+$ resources (set resource) :: Resources are a set of resources
	::
	+$ network :: A network is like a social network...think subreddits or twitter lists or are.na collections. A node may occupy many positions in a network by being under multiple graphs
	$: graphs=(map resource (unit graph)) :: A list of resources (like [~zod %rants]) to a graph (a map of entities to nodes). Like on ~marpem/%permaculture, ~radbur-sivmus has a collection of saved posts about soil health
	tags=(set term) :: tags, which are the terms used in the network (a list of communities, perhaps, or more generally the way people categorize things on the network)
	tag-queries=(map term resources) :: tag-queries are terms mapped to resources. So %my-posts = (set resource), or /r/permaculture = (set resource)
	==
	::