Problem 1.9
[Problem adapted from © Chris Galitz CC BY NC-SA 4.0]
#| standalone: true
#| viewerHeight: 600
#| components: [viewer]
from shiny import App, render, ui, reactive
import random
import asyncio
import io
import math
import string
from datetime import datetime
from pathlib import Path
def generate_random_letters(length):
# Generate a random string of letters of specified length
return "".join(random.choice(string.ascii_lowercase) for _ in range(length))
problem_ID = "649"
w = reactive.Value("__")
L = reactive.Value("__")
weight = reactive.Value("__")
attempts = ["Timestamp,Attempt,Answer1,Answer2,Answer3,Answer4,Answer5,Answer6,Feedback\n"]
app_ui = ui.page_fluid(
ui.markdown("**Please enter your ID number from your instructor and click to generate your problem**"),
ui.input_text("ID", "", placeholder="Enter ID Number Here"),
ui.input_action_button("generate_problem", "Generate Problem", class_="btn-primary"),
ui.markdown("**Problem Statement**"),
ui.output_ui("ui_problem_statement"),
ui.input_text("answer1", "Your Answer 1 in units of lb", placeholder="Please enter your answer 1"),
ui.input_text("answer2", "Your Answer 2 in units of lb", placeholder="Please enter your answer 2"),
ui.input_text("answer3", "Your Answer 3 in units of lb", placeholder="Please enter your answer 3"),
ui.input_text("answer4", "Your Answer 4 in units of lb", placeholder="Please enter your answer 4"),
ui.input_text("answer5", "Your Answer 5 in units of lb", placeholder="Please enter your answer 5"),
ui.input_text("answer6", "Your Answer 6 in units of lb", placeholder="Please enter your answer 6"),
ui.input_action_button("submit", "Submit Answers", class_="btn-primary"),
ui.download_button("download", "Download File to Submit", class_="btn-success"),
)
def server(input, output, session):
# Initialize a counter for attempts
attempt_counter = reactive.Value(0)
@output
@render.ui
def ui_problem_statement():
return [
ui.markdown(
f"During engine work, a car's hood of length L = {L()} in. and width w = {w()} in., is propped up by rod AB. Hinges at C and D resist translation in the y- and z-directions but only D resists motion in the x-direction. If the hood weighs {weight()} lb, evenly distributed, determine the compressive force in rod AB and the reactions at C and D."
)
]
@reactive.Effect
@reactive.event(input.generate_problem)
def randomize_vars():
random.seed(input.ID())
L.set(random.randrange(50,70,1))
w.set(L()+random.randrange(10,20,1))
weight.set(random.randrange(30,80,1))
@reactive.Effect
@reactive.event(input.submit)
def _():
attempt_counter.set(
attempt_counter() + 1
) # Increment the attempt counter on each submission.
# Calculate the instructor's answer and determine if the user's answer is correct.
RDB = [-w()+12, 34.13, 37.9]
RDA = [-w()+6, 0, L()-2]
RDC = [-w(), 0, 0]
RDG = [-w()/2, L()/2*0.6691, L()/2*0.7431]
def vector_subtraction(RDB, RDA):
return [x - y for x, y in zip(RDB, RDA)]
RAB = vector_subtraction(RDB,RDA)
def vector_magnitude(RAB):
return math.sqrt(sum(x ** 2 for x in RAB))
RABmag = vector_magnitude(RAB)
FbarAB = [x/RABmag for x in RAB]
comp1 = RDB[1]*FbarAB[2]-RDB[2]*FbarAB[1]
comp2 = RDB[2]*FbarAB[0]-RDB[0]*FbarAB[2]
comp3 = RDB[0]*FbarAB[1]-RDB[1]*FbarAB[0]
FABCross = [comp1, comp2, comp3]
Weightj = [0, -weight(), 0]
comp4 = RDG[1]*Weightj[2]-RDG[2]*Weightj[1]
comp5 = RDG[2]*Weightj[0]-RDG[0]*Weightj[2]
comp6 = RDG[0]*Weightj[1]-RDG[1]*Weightj[0]
RDGCross = [comp4, comp5, comp6]
instr1 = comp4/comp1
Cract = [0,1,1]
comp7 = RDC[1]*Cract[2]-RDC[2]*Cract[1]
comp8 = RDC[2]*Cract[0]-RDC[0]*Cract[2]
comp9 = RDC[0]*Cract[1]-RDC[1]*Cract[0]
RDCCross = [comp7, comp8, comp9]
instr2 = comp2*instr1/comp8
instr3 = (comp3*instr1-comp6)/comp9
instr4 = -FbarAB[0]*instr1
instr5 = -FbarAB[1]*instr1+weight()-instr3
instr6 = -FbarAB[2]-instr2
correct1 = math.isclose(float(input.answer1()), instr1, rel_tol=0.01)
correct2 = math.isclose(float(input.answer2()), instr2, rel_tol=0.01)
correct3 = math.isclose(float(input.answer3()), instr3, rel_tol=0.01)
correct4 = math.isclose(float(input.answer4()), instr4, rel_tol=0.01)
correct5 = math.isclose(float(input.answer5()), instr5, rel_tol=0.01)
correct6 = math.isclose(float(input.answer6()), instr6, rel_tol=0.01)
if correct1 and correct2 and correct3 and correct4 and correct5 and correct6:
check = "All answers are correct."
else:
conditions = []
for i, correct in enumerate([correct1, correct2, correct3, correct4, correct5, correct6], start=1):
if correct:
conditions.append(f"correct for answer {i}")
else:
conditions.append(f"incorrect for answer {i}")
check = "; ".join(conditions) + "."
correct_indicator = "JL" if correct1 and correct2 and correct3 and correct4 and correct5 and correct6 else "JG"
random_start = generate_random_letters(4)
random_middle = generate_random_letters(4)
random_end = generate_random_letters(4)
encoded_attempt = f"{random_start}{problem_ID}-{random_middle}{attempt_counter()}{correct_indicator}-{random_end}{input.ID()}"
session.encoded_attempt = reactive.Value(encoded_attempt)
attempts.append(f"{datetime.now()}, {attempt_counter()}, {input.answer1()}, {input.answer2()}, {check}\n")
feedback = ui.markdown(f"Your answers of {input.answer1()}, {input.answer2()}, {input.answer3()}, {input.answer4()}, {input.answer5()}, and {input.answer6()} are {check}. For reference in debugging this, the calculated instructor answers are {instr1}, {instr2}, {instr3}, {instr4}, {instr5} and {instr6}")
m = ui.modal(feedback, title="Feedback", easy_close=True)
ui.modal_show(m)
@session.download(filename=lambda: f"Problem_Log-{problem_ID}-{input.ID()}.csv")
async def download():
final_encoded = session.encoded_attempt() if session.encoded_attempt is not None else "No attempts"
yield f"{final_encoded}\n\n"
yield "Timestamp,Attempt,Answer1,Answer2,Answer3,Answer4,Answer5,Answer6,Feedback\n"
for attempt in attempts[1:]:
await asyncio.sleep(0.25)
yield attempt
app = App(app_ui, server)