This is the Homwork for CP1-24 based on Edwin's Hubble paper on the velocity-distance relation of extra galactic nebulae. Everyone has to choose a task during the first day after publishing the homework. Tasks are distributed on a first come first serve basis starting with distributing tasks in class. The tasks have strict deadlines and depend on each other. Every task will be graded at the time it is due. Any missing task element at its deadline will be filled in by me. Everyone can ask the maintainers to review a PR (if one is available). The review should be completed immediately (2 hours) after assignment.
3 teams for 3 task groups:
Team Tools (2 members):
- Add github action for linting (flake8) (1 member) for all code (due till Monday 2pm)
- Add github action for unit testing (using pytest) (1 member) for all code (due till Wednesday 2pm)
- The team tools members are also the maintainer of this homework responsible for merging PRs. They can also assign reviews and review PRs.
Team Data and Documentation (3 members):
- Select the 9 groups (open circles) in Figure 1 of Hubble's 1929 article(due till Monday 2pm)(1 member)
- Describe in the documentation how the 9 groups were selected (1 member due at homework deadline)
- Compare the slope of the fitted straight line to Hubble's value of K and explain if there is a discrepancy (1 member due at homework deadline).
Team Algorithm (includes unit test and docstrings) (12+ members):
- Translate the pseudo-code below into python code (1 member) (due till Monday 2pm) with docstrings and unit tests (1 member) (due till Wednesday 2pm)
- Translate the pseudo-code below into C++ code (1 member due till Wednesday 2pm) that will be wrapped in a python function with docstrings and unit tests (1 member due till HW deadline)
- Make a least-squares fit with uncertainties to the 9 groups using the code above (1 member due till Wednesday 2pm).
- Write a function that takes lists of velocities and distances and returns a dictionary of the fitting parameters (1 member due till Friday 2pm) (including unit test and docstrings) (1 member due till HW deadline).
- Write a function that can estimate the age of the universe based on the data in the Hubble paper (1 member due till Friday 2pm) including unit test and docstrings (1 member due till HW deadline).
- Determine the 9 groups of the figure (see documentation team) and generate a csv file with the velocities and distances (1 member due till Wednesday 2pm).
- Programmatically read back in this data in your code to do the fit (1 member due till Friday 2pm) including unit test and docstrings (1 member due till HW deadline).
input data
n = size of data
if n < 2 :
print ‘Error! Not enough data!’
return
for i = 0... N-1 :
if abs( sigma_i ) < 0.00001 :
return
S += 1.0 / sigma_i**2
s_x += x_i / sigma_i**2
s_y += y_i / sigma_i**2
for i = 0... N-1 :
t_i = 1.0 / sigma_i * (x_i-s_x/S)
s_tt = t_i**2
b += t_i * y_i / sigma_i
if abs( S ) < 0.000001 :
return
a = (s_y - s_x * b) / S
b = b / s_tt
sigma_a2 = (1 + s_x**2/S*s_tt) / S
sigma_b2 = 1.0 / s_tt
for i = 0... N-1 :
chi2 += ((y_i - a - b*x_i)/sigma_i)**2
Note: Galaxy catalog available at (http://spider.seds.org/ngc/ngc.html).
| Homework Points | |||
|---|---|---|---|
| Interaction on project | |||
| Category | min per person | point factor | max points |
| Commits | 1 | 1 | 1 |
| Pull requests | 1 | 3 | 3 |
| PR Accepted | 1 | 4 | 4 |
| Other PR reviewed | 1 | 3 | 3 |
| Issues | 1 | 1 | 1 |
| Closed Issues | 1 | 1 | 1 |
| # Conversations | 25 | 1/5 | 5 |
| Total | 18 | ||
| Shared project points | |||
| # Milestones | 12 | 1/4 | 3 |
| Total | 21 | ||
| Result | |||
| Task completion | 21 | ||
| Sum | 42 |