Webwork2

[gebottomley]

Student entered in a value of -1/9, which was correct. WebWork scored it as incorrect even though when the instructor checks the answer, it says correct.

[Alex-Jordan]

If there is a bug, we will need some more information. Please provide the version of WeBWorK, the problem file (as an attachment), and the student's seed where the issue was observed.

Also, please confirm if the set was within the open/close date window for that student.

On Wed, Jan 31, 2024, 7:32 AM gebottomley @.***> wrote:

Student entered in a value of -1/9, which was correct. WebWork scored it as incorrect even though when the instructor checks the answer, it says correct.

— Reply to this email directly, view it on GitHub https://protect2.fireeye.com/v1/url?k=31323334-501cfaeb-3132feb7-454455535732-70072f80d8724894&q=1&e=f8299a5e-9704-4f0f-97b5-b95a542a4d31&u=https%3A%2F%2Fgithub.com%2Fopenwebwork%2Fwebwork2%2Fissues%2F2309, or unsubscribe https://protect2.fireeye.com/v1/url?k=31323334-501cfaeb-3132feb7-454455535732-4b05097172147c55&q=1&e=f8299a5e-9704-4f0f-97b5-b95a542a4d31&u=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FABEDOAHJDEHLD3JMP7BVHBLYRJPYLAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43ASLTON2WKOZSGEYTAMZXGUZTCNI . You are receiving this because you are subscribed to this thread.Message ID: @.***>

[gebottomley]

Thanks for the quick reply.

I verified that the response was within the open/close date window (1/11/2024). I've attached the problem.

How do I get WebWork to tell me the seed?

Best regards, Greg Bottomley

Set ID: ece410_spring2024_hw1 Set header file: defaultHeader Hardcopy header file: defaultHeader Open date: 01/10/2024 at 04:00pm EST Due date: 01/16/2024 at 11:59pm EST Answer date: 01/19/2024 at 07:30am EST Visible: yes Assignment type: default

On Wed, Jan 31, 2024 at 11:00 AM Alex Jordan @.***> wrote:

If there is a bug, we will need some more information. Please provide the version of WeBWorK, the problem file (as an attachment), and the student's seed where the issue was observed.

Also, please confirm if the set was within the open/close date window for that student.

On Wed, Jan 31, 2024, 7:32 AM gebottomley @.***> wrote:

Student entered in a value of -1/9, which was correct. WebWork scored it as incorrect even though when the instructor checks the answer, it says correct.

— Reply to this email directly, view it on GitHub < https://protect2.fireeye.com/v1/url?k=31323334-501cfaeb-3132feb7-454455535732-70072f80d8724894&q=1&e=f8299a5e-9704-4f0f-97b5-b95a542a4d31&u=https%3A%2F%2Fgithub.com%2Fopenwebwork%2Fwebwork2%2Fissues%2F2309>,

or unsubscribe < https://protect2.fireeye.com/v1/url?k=31323334-501cfaeb-3132feb7-454455535732-4b05097172147c55&q=1&e=f8299a5e-9704-4f0f-97b5-b95a542a4d31&u=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FABEDOAHJDEHLD3JMP7BVHBLYRJPYLAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43ASLTON2WKOZSGEYTAMZXGUZTCNI>

. You are receiving this because you are subscribed to this thread.Message ID: @.***>

— Reply to this email directly, view it on GitHub https://github.com/openwebwork/webwork2/issues/2309#issuecomment-1919406421, or unsubscribe https://github.com/notifications/unsubscribe-auth/BFXZEPM5URDZBHQTFUGAQQ3YRJTDPAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMJZGQYDMNBSGE . You are receiving this because you authored the thread.Message ID: @.***>

DESCRIPTION

Linear Algebra

ENDDESCRIPTION

KEYWORDS('matrix' 'addition')

DBsubject('Linear Algebra')

DBchapter('Matrices')

DBsection('Matrix Operations')

Date('')

Author('GEB based on problems by Bill Kranec')

Institution('NC State University')

################################################################# DOCUMENT();

loadMacros( "PGanswermacros.pl", "PGmatrixmacros.pl", "MathObjects.pl", "PGstandard.pl" );

Context("Matrix");

TEXT(beginproblem()); $showPartialCorrectAnswers = 1;

#################################################################

$A = new Matrix(2,2); $b = new Matrix(2,1);

deterministic values for testing

$a11 = 3;

$a12 = 1;

$a21 = 2;

$a22 = 4;

$b11 = 9;

$b21 = 16;

random values

$a11 = random(4,6,1); $a12 = random(1,3,1); $a21 = random(1,3,1); $a22 = random(7,9,1); $b11 = random(7,9,1); $b21 = random(10,12,1);

put into matrices to use matrix functions

$A->assign(1,1, $a11 ); $A->assign(1,2, $a12 ); $A->assign(2,1, $a21 ); $A->assign(2,2, $a22 );

$b->assign(1,1, $b11); $b->assign(2,1, $b21 );

################################################################# BEGIN_TEXT

Consider [ \mathbf{A} = \begin{bmatrix} $a11 & $a12 \ $a21 & $a22 \end{bmatrix}, \mathbf{b} = \begin{bmatrix} $b11 & \ $b21 & \end{bmatrix} ] $BR Compute the following: (a) { mbox( '(Ab = )', answer_matrix(2,1,5) ) } $BR (b) { mbox( '(A^T )', answer_matrix(2,2,5) ) } $BR (c) { mbox( '(b^T )', answer_matrix(1,2,5) ) } $BR (d) The determinant of (A =) { ans_rule(10) } $BR (e) { mbox( 'The inverse of (A =)', answer_matrix(2,2,5) ) } $BR END_TEXT #################################################################

$prod = $A$b; $prod11 = $a11 $b11 + $a12 $b21; $prod21 = $a21 $b11 + $a22 * $b21;

$AT = new Matrix(2,2); $AT->assign(1,1, $a11 ); $AT->assign(1,2, $a21 ); $AT->assign(2,1, $a12 ); $AT->assign(2,2, $a22 );

$bT = new Matrix(1,2); $bT->assign(1,1, $b11 ); $bT->assign(1,2, $b21 );

$det = $a11 $a22 - $a12 $a21;

$Ainv = new Matrix(2,2); $i11 = $a22/$det; $i12 = -$a12/$det; $i21 = -$a21/$det; $i22 = $a11/$det; $Ainv->assign(1,1, $i11 ); $Ainv->assign(1,2, $i12 ); $Ainv->assign(2,1, $i21 ); $Ainv->assign(2,2, $i22 );

ANS num_cmp( ra_flatten_matrix($prod) ); ANS num_cmp( ra_flatten_matrix($AT) ); ANS num_cmp( ra_flatten_matrix($bT) ); ANS num_cmp( $det ); ANS num_cmp( ra_flatten_matrix($Ainv) );

################################################################# BEGIN_SOLUTION

(a) [ \mathbf{Ab} = \begin{bmatrix} $a11 $b11 + $a12 $b21 \ $a21 $b11 + $a22 $b21 \end{bmatrix} = \begin{bmatrix} $prod11 \ $prod21 \end{bmatrix} ]

$PAR (b) [ \mathbf{A}^T = \begin{bmatrix} $a11 & $a21 \ $a12 & $a22 \end{bmatrix} ]

$PAR (c) [ \mathbf{b}^T = \begin{bmatrix} $b11 & $b21 \end{bmatrix} ]

$PAR (d) [ | \mathbf{A} | = $det ]

$PAR (e) [ \mathbf{A}^{-1} = \begin{bmatrix} $i11 & $i21 \ $i12 & $i22 \end{bmatrix} ]

END_SOLUTION ################################################################# ENDDOCUMENT();

[drgrice1]

You can find the student's seed by going to the homework sets editor, clicking on the numbers in the assigned users column, and then clicking on "Edit data for userId" for that user. The seed will be listed with the problem on the page that opens. This works for homework assignments at least. For gateway tests you have to do something a little different.

[gebottomley]

Thanks! The seed is 3524.

On Wed, Jan 31, 2024 at 12:01 PM Glenn Rice @.***> wrote:

You can find the student's seed by going to the homework sets editor, clicking on the numbers in the assigned users column, and then clicking on "Edit data for userId" for that user. The seed will be listed with the problem on the page that opens. This works for homework assignments at least. For gateway tests you have to do something a little different.

— Reply to this email directly, view it on GitHub https://github.com/openwebwork/webwork2/issues/2309#issuecomment-1919526317, or unsubscribe https://github.com/notifications/unsubscribe-auth/BFXZEPISKZUDBVBSDM5R27DYRJ2FRAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMJZGUZDMMZRG4 . You are receiving this because you authored the thread.Message ID: @.***>

[gebottomley]

It's strange that when I check the student's answer, it says it's 100% correct. Yet the grade is still 85/100. When I look at the answer history, the -1/9 part is marked in red, which I'm interpreting as WebWork considering the answer wrong.

Is there a way to tell WebWork to regrade a problem for a particular user? That might be useful in other situations as well.

[somiaj]

Could this be due to the assignment is in the reduced scoring period, and reduced score is being used. To me there are 5 answers, so getting one wrong should be 80% (4/5) and not 85%. The 85% grade makes me think it was a reduced score vs a wrong answer (just one more thing to double check).

[gebottomley]

Interesting. I didn't know there was such a thing as a reduced scoring period. I only see 3 dates: opens, closes, answers available.

Anyway, while there are 5 parts, some parts are matrices (multiple subparts) giving a total of 13 answers. The value -1/11 shows up in two places, giving a score of 11/13 or 85%.

On Wed, Jan 31, 2024 at 1:44 PM Jaimos Skriletz @.***> wrote:

Could this be due to the assignment is in the reduced scoring period, and reduced score is being used. To me there are 5 answers, so getting one wrong should be 80% (4/5) and not 85%. The 85% grade makes me think it was a reduced score vs a wrong answer (just one more thing to double check).

— Reply to this email directly, view it on GitHub https://github.com/openwebwork/webwork2/issues/2309#issuecomment-1919718848, or unsubscribe https://github.com/notifications/unsubscribe-auth/BFXZEPL55Q3FZPEVFYB7Y3TYRKGKDAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMJZG4YTQOBUHA . You are receiving this because you authored the thread.Message ID: @.***>

[Alex-Jordan]

You didn't say the version of WeBWorK you are using, but I cannot reproduce this when I enter the correct answers using the current version, WeBWorK 2.18. There are two instances of -1/9 in the matrix at the end, but it's accepted as correct when I submit. I know this is not inconsistent with what you said about the instructor checking the error.

Did you witness the student submit the "-1/9" and see what happened then? Have you examined the answer log to see the student really did enter "-1/9"? Is there any chance the "-" that the student entered was actually some special extended character set subtraction sign that this version of WW does not recognize? (Which can happen if a student copy-pastes the answer from somewhere.)

I don't think we generally use GitHub issues to troubleshoot and discuss potential bugs. That happens more in the WeBWorK forums. If discussion there leads to a confirmed bug, then we can address it here. So I'm closing this issue for now, and it can be reopened later if appropriate. If it does get reopened, please give the issue a clear title.

[Alex-Jordan]

Also, if there is an issue here, some thought can be given to if it is a webwork2 issue, or a pg issue. In general (but not always) something about bad problem behavior will be a pg issue (the problem processing engine) not a webwork2 issue (the user interface). Of course it helps to understand the issue more to know where this would belong.

[gebottomley]

Hi,

Thanks for your emails. We're using WebWork version 2.15.

So I'm attaching a screen shot of the history of the student's input. As you can see, the -1/9 entries are in red. Notice that the first attempt had the wrong answer. It's as if WebWork couldn't change its mind when later attempts were correct.

Also attaching a screen shot of what I see when I click check answers on the student's problem. Notice that is shows all green and states all answers correct but still shows 85% for the problem. Is WebWork supposed to regrade when I do this?

Best regards, Greg

On Thu, Feb 1, 2024 at 1:17 AM Alex Jordan @.***> wrote:

Also, if there is an issue here, some thought can be given to if it is a webwork2 issue, or a pg issue. In general (but not always) something about bad problem behavior will be a pg issue (the problem processing engine) not a webwork2 issue (the user interface). Of course it helps to understand the issue more to know where this would belong.

— Reply to this email directly, view it on GitHub https://github.com/openwebwork/webwork2/issues/2309#issuecomment-1920588853, or unsubscribe https://github.com/notifications/unsubscribe-auth/BFXZEPO6PA6DRWWOFY25R7LYRMXQHAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMRQGU4DQOBVGM . You are receiving this because you authored the thread.Message ID: @.***>

[Alex-Jordan]

The screenshot did not make the post.

[drgrice1]

Webwork is not supposed to regrade when you check answers on a student problem.

As @Alex-Jordan noted, your screenshot did not make the post. Also noted by him, this is not the correct place for this. Start on the forums, and try to work it out there. If a big can be determined that is valid for the latest WeBWorK release, and has not been fixed in the develop branch, then an issue is appropriate. Since you are in a rather old version of WeBWorK, and we can not reproduce your issue, I doubt this is a valid issue.

[gebottomley]

Here are the screen shots. Sorry to raise the issue in the wrong place. I used the link the old WebWork pointed me to.

[Alex-Jordan]

I'm afraid that so much has changes from 2.15 to 2.18 that it isn't feasible for us to look into this. Quick attempts with version 2.18 are unable to reproduce the issues. Changes from 2.15 to 2.18 have touched on fractions, matrices, answer input fields, and alternate "minus" sign characters, all of which could be at play here. And that's just a list from the top of my head. I recommend upgrading to 2.18 (or 2.19, coming late spring or summer) when you are able to.

[gebottomley]

Sounds good. Thank you so much for looking into this. This will give me reason to encourage our IT folks to upgrade.

Best regards, Greg Bottomley

On Thu, Feb 1, 2024 at 3:42 PM Alex Jordan @.***> wrote:

I'm afraid that so much has changes from 2.15 to 2.18 that it isn't feasible for us to look into this. Quick attempts with version 2.18 are unable to reproduce the issues. Changes from 2.15 to 2.18 have touched on fractions, matrices, answer input fields, and alternate "minus" sign characters, all of which could be at play here. And that's just a list from the top of my head. I recommend upgrading to 2.18 (or 2.19, coming late spring or summer) when you are able to.

— Reply to this email directly, view it on GitHub https://github.com/openwebwork/webwork2/issues/2309#issuecomment-1922210009, or unsubscribe https://github.com/notifications/unsubscribe-auth/BFXZEPJZQ3QSXHO7MJTHXS3YRP43HAVCNFSM6AAAAABCTIVKHOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMRSGIYTAMBQHE . You are receiving this because you authored the thread.Message ID: @.***>