STACK

Regine,
I'm a huge fan of Geogebra and hand used it a lot in my teaching, (and for generating LaTeX output for traditional paper-based handouts). As far as STACK integration is concerned, GeoGebra is not GPL, and has a "non-commercial" licence. It is also difficult to avoid cross-site scripts (I think, but it has been a while since I checked this technical question). STACK has a lot of commercial partners, and users, and for this reason I put my effort into supporting graphics which have an open source codebase. Currently we have the Maxima "plot" commands. We also have JSXGraph support, but really need more examples and better STACK-JSXGraph documentation. I'm very happy to support GeoGebra as it is excellent, and this is in no way a criticism of their work. I'm very happy to include examples etc, and to support users who make use of GeoGebra. I just want to keep the core functionality (and develop new core functionality) which is less restricted.
Chris

Hi, I am relatively new in using stack in moodle. In the meantime, I've read a lot about what I found mostly about Google.
Yesterday I read that Geogebra can also be loaded as a plugin in Moodle and then acted with stack. Maxima can accomplish a lot, but especially for graphics you are a bit limited, because the package "draw" is not yet supported. My question is, if you can use Maxima and Geogebra together in Stack with Moodle? that would have to load the administrator, right?
I'm also looking for a way to query students for the domain of a function. Often the answer is "\ mathbb {R} \ backslash \ {x_1, x_2, \ dots \}", but I can not query that because each answer should be a maxima expression. Can anybody help me further?
Regine

This is an incredible plugin for all science courses involving computation and especially for mathematics. A well designed quiz with the STACK question type together with good multi-media course material can do a fantastic job for helping students self-learn. The contributions of the developers of this plugin are great indeed. A great benefit of this STACK question type is exquisite control of the incredibly complex interactive nature of self-learning. I cannot recommend this plugin highly enough to the Math and Science teachers.
I am using it for Moodle 3.5 and barring for some minor errors, still works. I am eagerly awaiting the official version for Moodle 3.5.

Thanks Stuart, I've updated this to https://stack.maths.ed.ac.uk/demo/

Chris: The link to http://stack.bham.ac.uk is broken (at least today it is). Have Birmingham taken your site down since you left? Should it now be a Newcastle URL?

It is OK to put evertyhing on the same server. Using a separate pool server gives slighly faster performance, and more security and scalability, but it is another thing to set up.

Some of our lecturers would like to use Stack in their courses. I am not sure whether to put everything on the Moodle server or to set up a separate server for Maxima (with pool). I would like to know how much (additional) load Stack/Maxima create create on a Moodle server. We have a single Moodle server at the moment but are changing to a load-balanced setup in summer 2018.
Wolf

It so that my student can directly enter base 16 or base 2 without it being incorrectly interpreted. Even for the character entry field, it seems to try and interpret the text as an expression.

Stephen,
Sorry, I forgot to mention that students can type in a Maxima string e.g. "Hello world". They need to use the quotes to make it a Maxima expression. This, of course, is not really a sensible input mechanism!
Chris

Stephen,
The fundamental design of STACK is that *every* answer should be a Maxima expression.
The answer tests String, StringSloppy and RegExp are provided so that string matches can be done on the internal Maxima string representation of a mathematical expression. They were not, originally, designed to assess strings as student's answers.
I recently added the "notes" input. This input is not assessed automatically by STACK, and students can use it to record working, or comments for the teacher. It would be possible to add in a "string" input type, which wraps the student's answer in string quotes to create a valid maxima object.
Can I ask why you need to do this? Sometimes, the underlying need can be done with another method.
I'm happy to talk about adding support for strings if there is a genuine need.
Chris

Hi Chris,
How do I get STACK to allow text entry of a string? We have String, StringSloppy and RegExp tests, but I keep getting unknown function errors because it's trying to interpret the answer as algebra.

Stephen,
Why don't you email me (C.J.Sangwin@ed.ac.uk) with a couple of question on paper and we can work together to develop some examplars? I'm keen to get this right, and there are lots of options in the interface.
The short answer to 1 is "not currently". I let Dragmath slide after the Java browser security issues, and a general lack of time. A good Javascript maths editor would be a great project generally.
Chris

I ma running STACK 4.0 latest on 3.1 and I've been experimenting with trying to get it to recognise boolean algebra questions. It has some quirks which have me stuck currently:
1. Is there a way of using an equation editor, other than dragmath (which seems to be dying because of browser based Java dying) for a student to enter the answers?
2. In the validation panel, when my student types in an answer (long hand), it will convert some operations to the correct symbols, but not others. So if they type in not(A) or not(B) the "not" operators get converted, but not the "or" operator. Is this a bug? any ideas where please?
3.When it comes to checking the correctness of the answer in preview I can only see the correct or incorrect user type message I have to go the status variable further down in the technical small print. This seems to affect all stack questions currently and the show whether correct option seems to have no effect.
4. Which answer test would you recommend?
5. With AlgEquiv and CasEquiv Sometimes the answer gives status:correct, but mostly it gives status:giveup.
Please help!

Hey guys,
If someone else has maxima version 5.38.0 on CentOS 7 installed from the EPEL repo, the STACK optimisation doesn't currently work. Rebuilding 5.38.1 from source, seems to solve the problem.
See https://moodle.org/mod/forum/discuss.php?d=357750 for more information.
Cheers, Joël

Thanks for the question Phan Chon,
I'm in the process of final testing for STACK 3.6 and STACK 4.0 (both will be released within days of each other. STACK 4.0 is an irreversible upgrade). They will both work with Moodle 3.3.
Chris