pavel-kirienko

/// Pseudo-inverse of a matrix. There may be a more efficient solution for square matrices; this is a general one.
/// Tolerance less than epsilon*10 may cause numerical instability.
template <auto R, auto C, typename S>
[[nodiscard]] Eigen::Matrix<S, C, R> pinv(const Eigen::Matrix<S, R, C>& a, const S tolerance = std::numeric_limits<S>::epsilon() * 10)
{
    const Eigen::JacobiSVD<Eigen::Matrix<S, R, C>> svd(a, Eigen::ComputeFullU | Eigen::ComputeFullV);
    Eigen::Matrix<S, C, R>                         si;
    si.setZero();
    for (int i = 0; i < svd.singularValues().size(); ++i)
    {

pavel-kirienko

#!/bin/bash
# https://gist.github.com/pavel-kirienko/32e395683e8b7f49e71413aebf5e1a89
# Pavel Kirienko <pavel@opencyphal.org>

HELP="Register slcan-enabled serial-to-CAN adapters as network interfaces.
Usage:
    `basename $0` [options] <tty0> [[options] <tty1> ...]

Interface indexes will be assigned automatically in ascending order, i.e., the
first device will be mapped to slcan0, second to slcan1, and so on.

pavel-kirienko

#!/usr/bin/env python
# Bulk usage:
#   find . -name '*.[ch]pp' -exec bash -c 'recomment.py < "{}" > "{}.out" ; mv "{}.out" "{}"' \;

import sys, re

RE_REPLACE = re.compile(r"(?m)^(\s*?) ?\*(.*)")

def replace_one(match) -> str:
    use_doc = bool(match[1])

pavel-kirienko

# Capture high-frame-rate, high-resolution video of the desktop using ffmpeg.
# The key options are: -c:v libx264 -f flv -vb 1000M -deadline realtime -cpu-used 12
# Without these, the output video peaks at ~5 fps or so.

ffmpeg -video_size 3840x2080 -f x11grab -i :0.0+3840,0 -c:v libx264 -f flv -vb 1000M -deadline realtime -cpu-used 12 output.mp4 -y

pavel-kirienko

# By default, X-Box 360-compatible controllers are detectable but dysfunctional because they expect the host
# to send a particular USB control transfer with some sort of initialization command.
# This udev rule will invoke a trivial Python script automatically when the gamepad is connected that emits
# the required initialization command.
#
# Integration:
# 1. Put this rule into /etc/udev/rules.d/51-xbox-gamepad.rules
# 2. Install pyusb for the root's Python:   sudo pip install pyusb
# 3. Reload udev rules as root:             udevadm control --reload-rules && udevadm trigger
#

pavel-kirienko

#!/bin/bash
# Convert all video files in the current directory into gifs.
# Silently overwrite existing files.
# This is useful for working with matplotlib animations.
for src in *.mp4
do
    bn="${src%.*}"
    echo "$src $bn"
    ffmpeg -y -i "$src" "${bn}.gif" || exit 1
done

pavel-kirienko

# The part .data=0x08000000 should be replaced with the correct base offset of the ROM.
# The value 0x08000000 is valid for STM32.
arm-none-eabi-objcopy -I binary -O elf32-little --change-section-address .data=0x08000000 input.bin output.elf

pavel-kirienko

def run():
    rpm_setpoint = 0
    going_down = False
    step = 2
    def update():
        nonlocal rpm_setpoint
        nonlocal going_down
        rpm_setpoint += (-step if going_down else step)
        broadcast(uavcan.equipment.esc.RPMCommand(rpm=[rpm_setpoint]))
        if going_down:

pavel-kirienko

#!/bin/bash
#
# Backup server web interface (CGI script).
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions: