Crash right after starting Sequalator: "could not find or load the Qt platform plugin 'windows'"

[ComFreek]

Hello Sumit Bongir,

Thank you for your email and accepting my request. The bug report is as follows:

OS: Windows 8 Pro 64-bit

Sequalator version 1.20.0 64-bit

Desc.: After starting Sequalator/sequalator.exe, I get the error messages below:

Regards

ComFreek

[Sumit Bongir]

Hello ComFreek,

From first cut look it seems to me that the issue is probably with Qt deployment.
I have created a discussion in the Qt forum and will get back to you with a solution ASAP.

Meanwhile can you please try the previous version Sequalator 1.18.2 which is also available on the Downloads page?
Sequalator 1.20 is built using Qt 5 and Sequalator 1.18 is built using Qt 4.
This will help us in trying to find the root cause of the problem.

As I have developed and tested all the versions of Sequalator in Windows 7, you should definitely not experience this problem on it.
So if you have access to Windows 7 my suggestion is to use Sequalator on it as a temporary work around.

Regards,
Sumit

[ComFreek]

Hello Sumit,

I am sorry for the late reply.

Sequalator 1.18.2 does work :) One question though: there was a dialog saying that all my "hardware data" gets copied. Where got the copy sent to?

Unfortunately, I do not have another Windows machine available for testing purposes.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

Thank You for confirming about Sequalator 1.18.2. The issue in Sequalator 1.20.0 is due to a missing dependency that was added in Qt5.
All previous versions of Sequalator were built using Qt4 and do not have this issue.
I will fix the issue with Sequalator 1.20.0 by Sunday, until that you can continue using Sequalator 1.18.2.
I am sorry that you had to go through all this trouble and I appreciate your co-operation in trying to fix the issue! :)

Regarding the hardware data asked by you, it is some text data used to uniquely identify your hardware which is for creating the license file.
It consists of OS, User account name and Computer name.
Refer the Registration page for more details.

Looking forward to your feedback of Sequalator and continued active membership in this group!

Regards,
Sumit

[ComFreek]

Hello Sumit,

Frankly speaking, I dislike the registration compulsion very much:

1. The license depends on the PC name. What am I supposed to do if I want to carry Sequalator on my USB flash drive to run it on other PCs than mine?

2. If I don't register Sequalator, I will always have to wait 10 seconds for Sequalator to start. This behavior is annoying.

3. I do not want to share my full name (=my Windows account name) just to overcome the startup penalty time.

I understand that you want to collect statistical information about your target group, but the current registration model is too restricting in my opinion.

Another topic: I've got a feature request:

Don't clear the whole table if the user clicks adds or removes a variable. The user experience would be improved if you retained the variables which are not affected by the addition or removal of a variable.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

Frankly speaking, I dislike the registration compulsion very much:

Firstly the registration is not at all compulsory!
You only do it if you want to remove the 10 second penalty.

1. The license depends on the PC name. What am I supposed to do if I want to carry Sequalator on my USB flash drive to run it on other PCs than mine?

You can carry Sequalator in a flash drive and use it on any PC you want without having to register. The only drawback is the 10 second penalty.
If you are going to use Sequalator on multiple PC's then I suggest you add the Sequalator generated hardware information for all PC's and paste it only during a single registration. I will mail you the license files for all the PC's. You only need to register once!

2. If I don't register Sequalator, I will always have to wait 10 seconds for Sequalator to start. This behavior is annoying.

Since I am not charging anything and so little personal information is captured during registration, I am unable to understand why you feel uncomfortable to register.
Please rest assured that the data collected rests only on a Google Docs file online and I have no interest in using it for any unethical activity.
Seriously the only reason I am keeping the registration process is so that I have some idea of how many people are using my software, that's it!

3. I do not want to share my full name (=my Windows account name) just to overcome the startup penalty time.

You can create a new User Account on Windows with very limited restrictions. This has 2 advantages:
1. You don't have to share your name with me.
2. There is added comfort of security provided to you by Windows.

Another topic: I've got a feature request:

 

Don't clear the whole table if the user clicks adds or removes a variable. The user experience would be improved if you retained the variables which are not affected by the addition or removal of a variable.

This behaviour is on purpose and I had to think a lot and make this cruel decision...
The idea is that you use a spreadsheet software like MS Excel (not free) or LibreOffice (free) for managing/editing your data.
These software are meant for such purposes only and there is no need to re-invent the wheel in Sequalator IMHO.
The Sequalator text file (.seq) can be interchangeably opened in Sequalator and MS Excel.
So, you create the required no of variables in Sequalator then save the file.
You open this file in MS Excel and paste only the required data and then save the file which will open without any issues in Sequalator.

You may ask why not simply keep the existing data when user changes the no of variables.
I feel that is a terrible UX concept as the user may change the no of variables by mistake and get wrong answers.
I hope you can understand why I kept it this way.
Please feel free to argue with me... :)

And BTW I fixed the Sequalator 1.20.0 issue!
Please let me know in case you come across any more issues.

Regards,
Sumit

[ComFreek]

Hello Sumit,

I see.

I submitted the registration formular and I've already received an answer from you. Thanks for the fast reply!

Unfortunately, Sequalator does not seem to notice the registration file in %appdata%\Sequalator\Registration\Sequalator.regseq. It still displays the information message about registering a copy.

I feel that is a terrible UX concept as the user may change the no of variables by mistake and get wrong answers.

Wouldn't a normal user notice that he/she changed the number of variables?

In my eyes it's far more probable that a user changes the number of variables by mistake and loses some data.

Oh, wait a second. I just discovered the undo/redo features. Of course the point of losing some data is invalid now.

You open this file in MS Excel [...]

I didn't know this feature existed.

What about a button in Sequalator which opens Microsoft Excel (- if installed)?

Sequalator 1.20.0 works fine now! Thanks for fixing the bug!

Regards,

ComFreek

[ComFreek]

Hello Sumit,

thank you for the your mail with the new license file. It works like a charm now :)

Recently, I experience a new "bug": a black rectangle is being displayed at the bottom of the application.

Neither resizing the window nor deactivating OpenCL acceleration nor choosing the fancy UI resolves the problem.

(Frankly speaking, I don't consider it a bug or a major issue at all. It does not prevent me from using the application. I just wanted to let you know about this behavior.)

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

Glad to hear that the license issue has been resolved!
Actually the black box you are referring to is the Status Bar and it is as intended.
Usually people never look at the status bar whilst it displays really informative messages.
So I inverted the black and white colour combination to draw attention to it.
You may have noticed that the Status Bar shows necessary messages whenever required.
Also when you hover over a button, it will show a short description of the button.
How has your experience with OpenCL been so far?
What do you feel about the fancy UI?
Thanks for continually providing your constructive feedback :-)

Regards,
Sumit

[ComFreek]

Hello Sumit,

I am not able to activate OpenCL acceleration (it doesn't save the settings). Actually, I am not even able to close Sequalator without killing the process.

The fancy UI isn't bad, but I prefer the normal UI (unfortunately, I cannot switch back anymore due to the crash described above).

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

I am not able to understand your exact problem, but I will suggest you a solution.
1. Close all instances of Sequalator
2. Open Windows Explorer and type the following address: %APPDATA%\Sequalator
3. Now delete the Preferences folder.
4. Start Sequalator
5. Go to Tools -> Options -> User Data and enable Hardware Acceleration using OpenCL
6. Press OK
7. Press OK
8. Close Sequalator
9. Start Sequalator.
You should now be able to solve your equations on the GPU without any problems.

The situation that you are experiencing may arise if you are using multiple versions of Sequalator simultaneously i.e. Sequalator 1.18.2 and Sequalator 1.20.0 for example.
Since the preferences file varies for both the versions, you are experiencing this anomaly.
I would suggest you to only use Sequalator 1.20.0 henceforth.
If the problem is still not solved maybe you can explain in more details so that I would be able to muse and provide my prognosis.

Regards,
Sumit

[ComFreek]

Hello Sumit,

the deletion of the preferences folder solved the problem. Thanks!

I've just tested a system of linear equations with 14 equations. It works equally fast on the CPU and the GPU. I cannot notice a difference. I would be interested in a stress test file whose solving process is faster on the GPU. Do you have such a file or any information on how many equations I need for a noticeable speed difference?

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

A system of 14 linear equations is too little to compare...
You should at least try for 1000 equations.
On my laptop it takes 962 ms to solve on the CPU while it takes 9962 ms on the GPU.
As you can see the OpenCL code is 10X slower than the multi-threaded CPU code.
The CPU code is much faster because its algorithm is cache friendly.
The algorithms required to solve equations using OpenCL are not so efficient as it requires a lot of data transfer and memory management.

The reason Sequalator supports OpenCL solver is that it can run on any device available i.e. CPU, GPU, etc.
Each device has its own accuracy and so the results obtained for the same set of equations will vary as per the device.
So if your default CPU has poor accuracy, you can use the OpenCL solver to run on a device which has better accuracy to get better solutions.
However if your default CPU has good accuracy then you may never have to use the GPU solver.
During my testing though, I found a particular set of equations which was giving much more precise solutions on the GPU rather than the CPU despite the CPU having the better accuracy.

You can easily generate a set of equations with required no of variables in Sequalator. Follow these steps:
1. Tools -> Options -> Benchmark
2. Enter the required no of variables and press start
3. If you don't want to solve using OpenCL press cancel in the next dialog
4. After the benchmark is complete it will ask if you want to save the benchmark file
5. Press Yes and provide the location where you want to save

I am eager to see the benchmark results on your PC!
Feel free to ask me if you want to know more ;)

Regards,
Sumit

[ComFreek]

Hello Sumit,

I totally forgot to answer here despite having already made the benchmarks :)

Here are my benchmark results:

+-------------------+---------------------+-----------------+-------------------+
|        CPU        | Number of variables |      10000      |        -/-        |
+-------------------+---------------------+-----------------+-------------------+
| Description       | Time Required       | % of Total Time | Time per Equation |
|                   |                     |                 |                   |
| Initialise        | 0.224               | 0.0581456       | 2.24e-05          |
| Generate Nos.     | 4.68                | 1.21483         | 0.000468          |
| Save To File      | 43.737              | 11.3532         | 0.0043737         |
| Open File         | 28.038              | 7.27806         | 0.0028038         |
| Solving Equations | 308.561             | 80.0958         | 0.0308561         |
| Total Time (sec)  | 385.24              | 100             | 0.038524          |
+-------------------+---------------------+-----------------+-------------------+

+-------------------+---------------------+-----------------+-------------------+
|        GPU        | Number of variables |      10000      |                   |
+-------------------+---------------------+-----------------+-------------------+
| Description       | Time Required       | % of Total Time | Time per Equation |
|                   |                     |                 |                   |
| Initialise        | 0.242               | 0.0600756       | 2.42e-05          |
| Generate Nos.     | 5.036               | 1.25017         | 0.0005036         |
| Save To File      | 46.433              | 11.5268         | 0.0046433         |
| Open File         | 29.879              | 7.41735         | 0.0029879         |
| Solving Equations | 321.236             | 79.74568        | 0.0321236         |
| Total Time (sec)  | 402.826             | 100             | 0.0402826         |
+-------------------+---------------------+-----------------+-------------------+

Roughly speaking, it seems that my CPU is faster than my GPU. (Note however that I only did one benchmark. The difference could also be a result of random errors!)

I've finally found a bug (which is not by design): I cannot save the benchmarks. Although I specify a file name, Sequalator doesn't save any file. This bug happens always.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

I am glad to see your benchmarks!
Way ahead of my Laptop :-)
In order to standardise the whole process for the future I have created a guide for creating benchmarks.
You may follow these steps so that your benchmarks are visible to everyone on the blog.
From the results I feel the CPU benchmarks are performed using the OpenCL solver.
If instead you use the multi threaded CPU solver (by disabling the Hardware Acceleration) you will get a tremendous boost in performance.

Regarding the bug, Yes I accept that it is a fault and needs to be corrected.
I have updated the same in the Sequalator bugs tracker.
Since it is not a critical bug, I will fix it in my next build.
Actually I don't have anything major as of now apart from the bug fix for the next build.
So can you suggest some changes/improvements that you feel are required in Sequalator?

Regards,
Sumit

PS: I loved your ASCII art table ;-)

[ComFreek]

Hello Sumit,

I created an own thread inlcuding by benchmark results as per your guidelines.

How do I know which GPU Sequalator uses? It doesn't show me a dialog to choose one GPU from.

I have two GPUs: an Intel on-board GPU and an "extern"/real GPU.

Both are enabled in the BIOS and the correct drivers are also installed.

Regards,

ComFreek

PS: I used an online for creating the ASCII tables: http://www.sensefulsolutions.com/2010/10/format-text-as-table.html ;)

[Sumit Bongir]

Hello ComFreek,

First of all Thanks for posting the Sequalator benchmark results on your PC!
Sequalator as of now only supports dedicated GPU hardware.
Unfortunately integrated Intel GPUs are not supported as they have some special requirements.
The OpenCL solver is not fully developed yet and you can expect a lot more optimisations and improvements in the future.

I feel there are some things missing in your benchmark.
When you enable Hardware Acceleration i.e. OpenCL, the next time you solve equations you should first see the dialog for OpenCL devices.
This dialog lists all the compatible OpenCL devices.
If you are not getting this dialog then that means OpenCL is not enabled.
If you are getting this dialog then you can easily select the device on which you want to perform the computation.
Additionally you can add this dialog's screenshot to your benchmarks thread.

I hope this clears your doubt.
Please let me know if there is any confusion.

Regards,
Sumit

PS: I have bookmarked that blog for future reference ;)

[ComFreek]

Hello Sumit,

I never see the dialog for OpenCL devices, irrespective of the hardware acceleration mode being activated or not.

I've got a suggestion: Bundle Sequalator with an official installer instead of a ZIP archive. I quite like to have a list of all installed programs available in the control panel because I am not required to remember the location where I had put the software. It also eases the migration to a new PC (or to a reinstallation of the OS) since the application appears on that list, so I won't forget about it.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

I think there is some problem in your case with the OpenCL plugin.
I am working on the next update in which I am planing on changing the UI for the OpenCL devices a bit.
Hopefully this should clear some confusion.
Apart from that, the bug reported by you has been fixed for the next update.

My initial idea behind providing zip files instead of installers was to provide portability.
But I have realised that zip files can be cumbersome during manual updation.
So I am now trying to use NSIS for the installer.
I guess I would be in a position to release the update in a couple of weeks.

Regards,
Sumit

[ComFreek]

Hello Sumit,

that's great!

Providing a ZIP and an installer option would be another possibility, but that's probably overkill.

I am looking forward to hearing news from you. Let me know if something needs to be tested.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

First of all sorry for the delay in reply. It is festive season here in India and learning NSIS was not very quick (read easy ;-) ).
I have released a new version of Sequalator.
Lots of your suggestions have been incorporated and I am looking forward to many more suggestions from you.
The major upgrade being that of the installer, I hope you have some respite now.
Also the solver selection UI has been improved so that it makes the process much more transparent for the user.
After clicking solve, Sequalator now throws a new dialog to select the solver.
If you are getting the OpenCL solver disabled then please hover the cursor over it to understand the reason for the problem.
If OpenCL solver is working good then please update the benchmarks.
Awaiting for your reply eagerly.

Regards,
Sumit

[ComFreek]

Hello Sumit,

the availability of an installer is great news!

I redid a benchmark and posted a new thread: https://groups.google.com/forum/#!topic/sequalator/HNyg365VMD8

I noticed that choosing the binary file type and setting UI mode to simple speeded up the computations. The first option seems logical to me, but I cannot (visually) see a difference between those UI modes Sequalator offers. Is there something going on behind the scenes? Shouldn't the stealth mode be faster?

If you are that eager to hear suggestions, here we go :)

• Open Sequalator, input nothing, press "Solve". You will get 3 error dialogs. One message dialog summing up all 3 errors would be much better.
• Attaching the "Analyse the Errors in Solutions & Equations" to a right side bar of the main window instead of a separate dialog window would also be more user friendly IMO.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

Thanks for benchmarking Sequalator on your PC!
Can you please post the image of the dialog which lists the OpenCL devices detected by Sequalator?
I have posted a similar image generated on my PC here.

Regarding the stealth mode, I don't think you will get any significant difference in speed between these two UI.
The difference would be in RAM usage as the stealth mode does not open the file to GUI.
But anyway looks like I have something to fix in this area.

I will incorporate the improvement regarding Messageboxes in the next release.
Regarding the analyse and errors dialog, I will see various possible changes and choose the best.
However the next release will take some time...
Have some really important tasks lined up for the next 2-3 months.

Regards,
Sumit

[ComFreek]

Hello Sumit,

Where can I open that dialog?

I don't get any additional dialog after clicking "Solve" in the dialog showing the two options "CPU solver" and "OpenCL solver".

Here are some stats (in seconds) regarding the UI modes:

+----------------+-------+--------+
| UI mode/solver |  CPU  | OpenCL |
+----------------+-------+--------+
| Simple         | 4.887 | 4.89   |
| Stealth        | 5.697 | 5.652  |
+----------------+-------+--------+

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

I have uploaded a video on YouTube which introduces some of the features of Sequalator.
http://www.youtube.com/watch?v=a9O3FW6DygY

Here I have shown how to solve by both the solvers.
I hope this helps resolve the issue.
If you are able to click the solve button for OpenCL solver but not getting the dialog then that means there was problem loading the OpenCL driver.
Can you please give some more details so that I can try to rectify the problem?

Regards,
Sumit

[ComFreek]

Hello Sumit,

nice explanatory video!

The dialog which appears in your explanatory video between 6:14 and 6:51 doesn't appear on my PC.

Which details do you need? My hardware and software details can be found in the benchmark thread.

I've discovered a minor issue:

1. Open Sequalator.

2. Enter the below values:

+---+----+----+---+----------+
|   | X1 | X2 | = | R. H. S. |
+---+----+----+---+----------+
| 1 |  3 |  4 | = |        6 |
| 2 |  1 |  2 | = |        5 |
+---+----+----+---+----------+

3. Solve (the solver doesn't matter).

4. Go to "Analyze errors in equations".

5. Select "Solution from file" for comparison.

6. Sequalator display a 100% error percentage. This happens because the current session is not saved yet.

Solution: display a text indicating that a comparison to the saved results (which don't exist yet) is illogical.

Another issue:

1. Open Sequalator and input the following values:

+---+----+----+---+----------+
|   | X1 | X2 | = | R. H. S. |
+---+----+----+---+----------+
| 1 |  3 |  2 | = |        9 |
| 2 | -6 |  2 | = |        0 |
+---+----+----+---+----------+

2. Solve and analyze the errors.

3. In the second row, the percentage is given as not available ("NA"). Why? The percentage should have been 0%.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

If even after selecting the OpenCL solver you are not getting the device selection dialog, then for sure OpenCL solver is not working on your PC.
There can be some reasons, one of them is that the OpenCL driver could not be loaded properly.
I will add some debug results to the log file in the next release. I think it should also show a message box to tell that there was some problem with the OpenCL solver.
I will add this in the next release.

Issue #1
If you may have observed in the table below the Analyse Solutions tab, it shows all variables as zero for From File.
This is the default value that I chose.
I could have chosen NA but I decided to keep it to zero.
But there can be an improvement, for example keeping the cells in some colour perhaps orange so that the user is aware that there the solutions are not saved to file.
Anyway you will not loose the data even in the current release as Sequalator will warn you of Unsaved changes while closing the window.

Issue #2
Please note that the RHS is zero and so is the LHS with the correct set of solutions.
What you say that it should be 0% is quite logical but is illegal mathematically.
0% means 0 out of 100, however we have 0 out of 0.
Anyway calculating percentage for that case is not possible as it is a 0/0 case which is indeterminate.
So that is why I kept it to NA.

Thanks for your detailed review after watching the video.
I am open to your considerations for the above mentioned issues.
Feel free to let me know in case I have been wrong.

Regards,
Sumit

[ComFreek]

Hello Sumit,

thanks for your reply and sorry for the delay on my side.

The log file is a good idea.

Issue #1

The problem I see is that you can't tell what '0' means in that context? Has no data been saved yet? Is it in fact zero?

In my opinion "NA" (or some similar text) would be the best option. An orange color must be explained somewhere in the dialog, I guess.

A more advanced method (that would probably require some time to be implemented) is to display a colored corner in the cells (as Excel does).

Issue #2

I see, it may be mathematically not valid, but from a user's perspective maybe not. If I have two results A=0 and B=0, there isn't any difference.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

In fact you can check even the current log file to see whether OpenCL was loaded or not.
Go to Tools -> Options -> Browse Application Local Files (This opens a folder named Sequalator).
Open the logs folder.
Now solve some set of equations using the OpenCL solver.
Now close Sequalator and open the session.log file in the logs folder.
It will print whether OpenCL was loaded or not.
Apart from this I am adding some more flags in the next version to try to trace down the problem.

Issue #1
Maybe it is getting complicated and confusing. OK then, I will change it to NA.

Issue #2
OK I will change it to 0%.

Regards,
Sumit

[ComFreek]

Hello Sumit,

the contents of session.log:

Turning off Debug.
Turning on Debug.
--> Found OpenCL Plugin
 
Application Exited with Error Code  0 .

 It apparently finds OpenCL, I'm looking forward to getting additional log information on that with your next update.

Regards,

ComFreek

[Sumit Bongir]

Hello ComFreek,

Sequalator 1.20.2 has been released with most of the changes as we discussed in this thread.
Do let me know if you face any difficulties.

Regards,
Sumit