🔒 Putting Matrices all on One Line | Python | Page 1

winged prairie Apr 12, 2024, 11:25 PM

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Need help with putting all the lines as one and now seperate.

rustic lightBOT Apr 12, 2024, 11:25 PM

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winged prairie Need help with putting all the lines as one and now seperate.

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@winged prairie

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winged prairie Apr 12, 2024, 11:30 PM

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helpers

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@helpers

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@deep belfry please if ou can help me out

deep belfry Apr 12, 2024, 11:41 PM

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winged prairie Need help with putting all the lines as one and now seperate.

is that all your code?

winged prairie Apr 12, 2024, 11:41 PM

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Yes

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It is a function call to it

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Here is the np.array functions

deep belfry Apr 12, 2024, 11:42 PM

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i've never worked with np, but if it is to do with python and not np functions im happy to help

winged prairie Apr 12, 2024, 11:43 PM

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That is np for python

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numpy as np

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@spice juniper

spice juniper Apr 12, 2024, 11:45 PM

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What?

deep belfry Apr 12, 2024, 11:45 PM

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just taggin random ppl 😭

winged prairie Apr 12, 2024, 11:45 PM

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I need some help with putting all the matrices one line as show in my screenshot

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@deep belfry he has helped me out in the past

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row_echelon_M

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spice juniper Apr 12, 2024, 11:46 PM

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@winged prairie no one is on-call to help you at any time, even if they've helped you in the past. so don't ping people to summon them to your question

winged prairie Apr 12, 2024, 11:47 PM

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Do get it

spice juniper Apr 12, 2024, 11:47 PM

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and don't post screenshots of text.

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!code

rustic lightBOT Apr 12, 2024, 11:47 PM

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winged prairie Apr 12, 2024, 11:47 PM

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def gaussian_elimination(A, B):
    """
    Solve a linear system represented by an augmented matrix using the Gaussian elimination method.

    Parameters:
    - A (numpy.array): Square matrix of size n x n representing the coefficients of the linear system
    - B (numpy.array): Column matrix of size 1 x n representing the constant terms.

    Returns:
    numpy.array or str: The solution vector if a unique solution exists, or a string indicating the type of solution.
    """

    ### START CODE HERE ###
    # Get the matrix in row echelon form
    row_echelon_M = np.linalg.solve(A,B)
    # If the system is non-singular, then perform back substitution to get the result. 
    # Since the function row_echelon_form returns a string if there is no solution, let's check for that.
    # The function isinstance checks if the first argument has the type as the second argument, returning True if it does and False otherwise.
    if not isinstance(row_echelon_M, str):
        return row_echelon_M
    ### END SOLUTION HERE ###
    
    
    return solution

deep belfry Apr 12, 2024, 11:50 PM

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winged prairie ```py def gaussian_elimination(A, B): """ Solve a linear system represen...

just convert it to a string?

winged prairie Apr 12, 2024, 11:51 PM

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If you can show me with the code as justr do the str() then

deep belfry Apr 12, 2024, 11:51 PM

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i've never used numpy, i dont know where the list is

winged prairie Apr 12, 2024, 11:52 PM

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Okay

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Do you know somebody who can help me out

deep belfry Apr 12, 2024, 11:53 PM

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winged prairie Do you know somebody who can help me out

no

winged prairie Apr 12, 2024, 11:54 PM

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Okay

split pilot Apr 13, 2024, 12:10 AM

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The arrays aren't correct.

winged prairie Apr 13, 2024, 12:10 AM

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Then how should they be then

split pilot Apr 13, 2024, 12:10 AM

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It should be 1d not 2d.

winged prairie Apr 13, 2024, 12:10 AM

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A = np.array([[1,2,3], [3,4,5], [4,5,6]])
B = np.array([[1], [5], [7]])

print(augmented_matrix(A,B))

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So I am wondering how I can do that

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@split pilot

split pilot Apr 13, 2024, 12:13 AM

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I'm confused. Why is it augmented_matrix now instead of gaussian_elimination?

winged prairie Apr 13, 2024, 12:14 AM

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It is a different function call as it does the same idea

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def augmented_matrix(A, B):
    """
    Create an augmented matrix by horizontally stacking two matrices A and B.

    Parameters:
    - A (numpy.array): First matrix.
    - B (numpy.array): Second matrix.

    Returns:
    - numpy.array: Augmented matrix obtained by horizontally stacking A and B.
    """
    augmented_M = np.hstack((A,B))
    return augmented_M

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There the code for it but am trying to focus on the gaussian_elimination

split pilot Apr 13, 2024, 12:16 AM

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Yes, but augmented_matrix returns an actual 2d array here: 3x4
On the other hand gaussian_elimination returns a 5x1 array when it's supposed to return a vector of length 5.

winged prairie Apr 13, 2024, 12:16 AM

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How would you suggest I fix it then

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Which place then

split pilot Apr 13, 2024, 12:20 AM

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You could .ravel() the matrix before returning it.

winged prairie Apr 13, 2024, 12:21 AM

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A = np.array([[1,2,3], [3,4,5], [4,5,6]])
B = np.array([[1], [5], [7]]).ravel()

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Like that

split pilot Apr 13, 2024, 12:22 AM

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I think return row_echelon_m.ravel()

winged prairie Apr 13, 2024, 12:23 AM

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That worked

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This took 3 weeks to solve it

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@split pilot thank you so much and would it be okay I can ask you future help

split pilot Apr 13, 2024, 12:24 AM

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I think it makes no sense to ask specific people for help. Better just put your question in a help channel.

winged prairie Apr 13, 2024, 12:25 AM

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Okay as thank you

split pilot Apr 13, 2024, 12:25 AM

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winged prairie Apr 13, 2024, 12:25 AM

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here was an error grading your submission. Details:
operands could not be broadcast together with shapes (8,) (4,)

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w2_unittest.test_gaussian_elimination(gaussian_elimination)

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I am getting this erro from this funciton

split pilot Apr 13, 2024, 12:26 AM

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What does that mean?

winged prairie Apr 13, 2024, 12:26 AM

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No idea

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https://stackoverflow.com/questions/63119831/how-to-solve-valueerror-operands-could-not-be-broadcast-together-with-shapes

split pilot Apr 13, 2024, 12:28 AM

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In this question on stackoverflow the OP tried to add a 1d array and a 2d array. Of course that's not possible.

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Do you try to add arrays in gaussian_elimination?

winged prairie Apr 13, 2024, 12:29 AM

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No not at all

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def gaussian_elimination(A, B):
    """
    Solve a linear system represented by an augmented matrix using the Gaussian elimination method.

    Parameters:
    - A (numpy.array): Square matrix of size n x n representing the coefficients of the linear system
    - B (numpy.array): Column matrix of size 1 x n representing the constant terms.

    Returns:
    numpy.array or str: The solution vector if a unique solution exists, or a string indicating the type of solution.
    """
    ### START CODE HERE ###
    # Get the matrix in row echelon form
    row_echelon_M = np.linalg.solve(A, B)
    # If the system is non-singular, then perform back substitution to get the result. 
    # Since the function row_echelon_form returns a string if there is no solution, let's check for that.
    # The function isinstance checks if the first argument has the type as the second argument, returning True if it does and False otherwise.
    if not isinstance(row_echelon_M, str):
        return row_echelon_M.ravel()
    ### END SOLUTION HERE ###
    
    
    return solution

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equations = [
[3, 6, 6, 8, 1],
[5, 3, 6, -10],
[4,- 5,8,8],
[4, 0,0, 0, 8,9]]

variables, A, B = string_to_augmented_matrix(equations)

sols = gaussian_elimination(A, B).split(',')

if not isinstance(sols, str):
    for variable, solution in zip(variables,sols):
        print(f"{variable} = {solution:.4f}")
else:
    print(sols)

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Sorry as lets solve one at a time

split pilot Apr 13, 2024, 12:32 AM

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numpy arrays don't have a split method.

winged prairie Apr 13, 2024, 12:32 AM

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Okay

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from utils import string_to_augmented_matrix

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There is the from utils

split pilot Apr 13, 2024, 12:34 AM

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Interesting. But equations isn't a string.

winged prairie Apr 13, 2024, 12:34 AM

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This coming rom a coursera course as no idea why for this error

split pilot Apr 13, 2024, 12:38 AM

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I think your equations already are an augmented matrix. Could that be?

winged prairie Apr 13, 2024, 12:38 AM

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Probably

split pilot Apr 13, 2024, 12:41 AM

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Probably you did something wrong then. Maybe you should find out what this function does.

winged prairie Apr 13, 2024, 12:41 AM

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I will

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equations = [
[3, 6, 6, 8, 1],
[5, 3, 6, -10],
[4,- 5,8,8],
[4, 0,0, 0, 8,9]]

variables, A, B = string_to_augmented_matrix(equations)

sols = gaussian_elimination(A, B)

if not isinstance(sols, str):
    for variable, solution in zip(variables,sols):
        print(f"{variable} = {solution:.4f}")
else:
    print(sols)

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from utils import string_to_augmented_matrix

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The code below will allow you to write any equation in the format it is given below (any unknown lower case variables are accepted, in any order) and transform it in its respective augmented matrix so you can solve it using the functions you just wrote in this assignment!
You just need to change the equations variable, always keeping * to indicate product between unknowns and variables and one equation in each line!

split pilot Apr 13, 2024, 12:45 AM

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What format is given below?

winged prairie Apr 13, 2024, 12:46 AM

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---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-40-a6ca3511c2c5> in <module>
      5 [4, 0,0, 0, 8,9]]
      6 
----> 7 variables, A, B = string_to_augmented_matrix(equations)
      8 
      9 sols = gaussian_elimination(A, B)

~/work/utils.py in string_to_augmented_matrix(equations)
      4 def string_to_augmented_matrix(equations):
      5     # Split the input string into individual equations
----> 6     equation_list = equations.split('\n')
      7     equation_list = [x for x in equation_list if x != '']
      8     # Create a list to store the coefficients and constants

AttributeError: 'list' object has no attribute 'split'

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There is no function defintion

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variables, A, B = string_to_augmented_matrix(equations)

split pilot Apr 13, 2024, 12:48 AM

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Yes, lists don't have a split method.

winged prairie Apr 13, 2024, 12:48 AM

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Do know as I think it just the grading system itself is the main issue

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Can you help me with back subsittuin then

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!pastebin

rustic lightBOT Apr 13, 2024, 12:49 AM

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winged prairie Apr 13, 2024, 12:49 AM

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https://paste.pythondiscord.com/G6ZA

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There is the equation itself

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Expected:
[-0.0841373 0.12363912 0.88135387 -2.83469018 -0.27829698 -3.87730702],
but got:
[-0.30941613 1.30319901 4.69817804 0.13843141 0.74359276 -3.87730702].

split pilot Apr 13, 2024, 12:50 AM

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The numbers are wrong.

winged prairie Apr 13, 2024, 12:50 AM

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Yes and so how can I do the right caluclations then for the equation

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A = np.array([[1,2,3],[0,1,0], [0,0,5]])
B = np.array([[1], [2], [4]])
row_echelon_form(A,B)

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w2_unittest.test_row_echelon_form(row_echelon_form)

spice juniper Apr 13, 2024, 12:54 AM

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winged prairie <@435555638886662175> thank you so much and would it be okay I can ask you futur...

As I said earlier, pinging people to summon them to your help is not allowed

winged prairie Apr 13, 2024, 12:54 AM

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Do know

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Was thanking

split pilot Apr 13, 2024, 12:56 AM

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I think there is a error in the formula.

winged prairie Apr 13, 2024, 12:56 AM

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Yes as I do agreed

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No idea what it might be

split pilot Apr 13, 2024, 12:59 AM

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Well, how does back substitution work?

winged prairie Apr 13, 2024, 12:59 AM

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No it does not as got the wrong numbers with the formula as no idea what the main issue could be

split pilot Apr 13, 2024, 1:00 AM

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That is because it does the wrong calculations.

winged prairie Apr 13, 2024, 1:00 AM

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What should it be then

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I tried to figure this out

split pilot Apr 13, 2024, 1:02 AM

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What is this line of code good for? row_to_reduce = row_to_reduce - value * substitution_row

winged prairie Apr 13, 2024, 1:03 AM

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Trying to do

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A = np.array([[1,2,3],[0,0,0], [0,0,5]])
B = np.array([[1], [2], [4]])
reduced_row_echelon_form(A,B)
array([[1., 2., 3., 1.],
[0., 0., 0., 1.],
[0., 0., 1., 0.]])

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M[j] = M[j] - value_below_pivot * M[row]

split pilot Apr 13, 2024, 1:05 AM

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Hm. But why would you multiply the M[row] with the value? I don't see how that makes sense.

winged prairie Apr 13, 2024, 1:06 AM

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What should I use then

split pilot Apr 13, 2024, 1:09 AM

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What do your debug prints say?

winged prairie Apr 13, 2024, 1:09 AM

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array([[1. , 2. , 3. , 1. ],
[0. , 1. , 0. , 2. ],
[0. , 0. , 1. , 0.8]])

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All tests passed

split pilot Apr 13, 2024, 1:09 AM

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"All tests passed" sounds great.

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So you fixed it already.

winged prairie Apr 13, 2024, 1:10 AM

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I did try put it shows the wrong numbrs

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array([[1., 2., 3., 1.],
[0., 0., 0., 1.],
[0., 0., 1., 0.]])

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It should be show thing

split pilot Apr 13, 2024, 1:11 AM

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I mean you have this debug print print(f"DEBUG: end result = \n{M}.")
It should show the final matrix after back substitution. And this matrix should consist mainly of zeroes.

winged prairie Apr 13, 2024, 1:12 AM

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[ 0. 0. 1. 1.]].
DEBUG: viewing row 1 ([ 0. 1. 0. -2.]) index 1 (1.0).
DEBUG: reducing row 0 ([1. 8. 0. 3.]) index 0 (1.0).
DEBUG: reducing using value = 8.0.
DEBUG: end result =
[[ 1. 0. 0. 19.]
[ 0. 1. 0. -2.]
[ 0. 0. 1. 1.]].
DEBUG: viewing row 0 ([ 1. 0. 0. 19.]) index 0 (1.0).
DEBUG: end result =
[[ 1. 0. 0. 19.]
[ 0. 1. 0. -2.]
[ 0. 0. 1. 1.]].

split pilot Apr 13, 2024, 1:13 AM

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Ah, that looks fine.

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I suppose the function is fine then for the input matrix.

winged prairie Apr 13, 2024, 1:14 AM

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Yes as it does

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Thank you

split pilot Apr 13, 2024, 1:14 AM

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So the bug must be elsewhere.

winged prairie Apr 13, 2024, 1:14 AM

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Yes

split pilot Apr 13, 2024, 1:18 AM

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Or maybe the function works for some test input, but not all test inputs. As the function makes some assumptions.

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The function assumes that the first non-zero value of each row is a 1.0.

winged prairie Apr 13, 2024, 1:20 AM

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What suggestion then

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!pastebin

rustic lightBOT Apr 13, 2024, 1:23 AM

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Pasting large amounts of code

If your code is too long to fit in a codeblock in Discord, you can paste your code here:
https://paste.pythondiscord.com/

After pasting your code, save it by clicking the Paste! button in the bottom left, or by pressing CTRL + S. After doing that, you will be navigated to the new paste's page. Copy the URL and post it here so others can see it.

split pilot Apr 13, 2024, 1:24 AM

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The suggestion is to satisfy that assumption.

winged prairie Apr 13, 2024, 1:24 AM

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https://paste.pythondiscord.com/SFSQ

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I acually got 100% on that as it now works as back_subtitution is the main issue now

split pilot Apr 13, 2024, 1:26 AM

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~~But it returns a Nx1 matrix instead of a vector. Not sure if that's correct.~~

winged prairie Apr 13, 2024, 1:26 AM

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Okay then how should I fix it then

split pilot Apr 13, 2024, 1:28 AM

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Ah, I'm sorry. I read that wrong. It actually returns a vector.

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So everything works. Great.

winged prairie Apr 13, 2024, 1:30 AM

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Yes

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Thank you again for the help and why spend this long with me

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.close

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!close

rustic lightBOT Apr 13, 2024, 1:42 AM

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Python help channel closed

This help channel has been closed and it's no longer possible to send messages here. If your question wasn't answered, feel free to create a new post in #1035199133436354600. To maximize your chances of getting a response, check out this guide on asking good questions.

#🔒 Putting Matrices all on One Line