NWChen

-- 1
myLast :: [x] -> x
myLast [] = error "Empty list"
myLast [x] = x
myLast (_:xs) = myLast xs

-- 2
myLength :: [x] -> Int
myLength [] = 0
myLength (_:xs) = 1 + myLength xs

NWChen

Doomsday algorithm

(given a date, what day of the week is it?)

1. What is <year>'s doomsday?

doomsday is the last day of February. In leap years, doomsday = 2/28. In normal years, doomsday = 2/29 doomsday in 2020 is Saturday, 2/29.

Given doomsday we can compute any day of the week in February:

• 2/15 = 2/29 - 2 weeks = Saturday
• 2/23 = 2/29 - 1 week + 1 day = Sunday

NWChen

PR2 manual

https://www.clearpathrobotics.com/wp-content/uploads/2014/08/pr2_manual_r321.pdf

Steps to reproduce

PR2 does not need to be connected to FETCH-WIFI (No ethernet cable).

1. Turn on PR2 and wait for 3 beeps on init.
2. Connect to PR2-wireless network.

SSID: PR2-wireless
PW: clearpath

NWChen

import matplotlib.pyplot as plt
import numpy as np

X = np.array([
    [0.8, 0.4],
    [0.3, 0.1],
    [0.8, 0.8],
    [0.4, 0.6],
    [0.6, 0.8],
    [0.4, 0.2],

NWChen

No typos will be found - file '/home/nwchen/Desktop/senior/os/spelling.txt': No such file or directory
No structs that should be const will be found - file '/home/nwchen/Desktop/senior/os/const_structs.checkpatch': No such file or directory
WARNING: Missing or malformed SPDX-License-Identifier tag in line 1
#1: FILE: f18-hmwk2-team12/kernel/kernel/ptree.c:1:
+#include <linux/err.h>

ERROR: open brace '{' following function definitions go on the next line
#9: FILE: f18-hmwk2-team12/kernel/kernel/ptree.c:9:
+void writepr(struct task_struct *root, unsigned long idx,
+	     struct prinfo *prarray) {

NWChen

set nocompatible
filetype off

" vundle runtime path
set rtp+=~/.vim/bundle/Vundle.vim
call vundle#begin()
Plugin 'VundleVim/Vundle.vim'

" vundle plugins
Plugin 'severin-lemaignan/vim-minimap'

NWChen

Exploratory analysis

Feature	Unit
TIME	s
T ATM	C
T MUSCLE	C
PWM	Hz
FORCE	N

NWChen

import subprocess
import re
import time
import httplib2 
import io
from apiclient.discovery import build
import os
import oauth2client
from oauth2client.file import Storage
from apiclient.http import MediaFileUpload, MediaIoBaseDownload

NWChen

#!/bin/bash

echo "starting hw1-part2"
source ~/fetch_ws/devel/setup.bash 
roslaunch fetch_gazebo playground.launch & 
sleep 10s
source ~/fetch_ws/devel/setup.bash 
roslaunch fetch_navigation fetch_nav.launch map_file:=EMPTY & 
sleep 10s
source ~/fetch_ws/devel/setup.bash

NWChen

import numpy as np
import cv2

face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')

def showCam():
        cam = cv2.VideoCapture(0)
        while True:
                ret_val, img = cam.read()