Cody

Rafael S.T. Vieira

4
Rank
86
Badges
39106
Score
1 – 50 of 5,756

Rafael S.T. Vieira submitted a Comment to Solution 3314043

No problem. And congratulations :)

3 hours and 1 minute ago

Rafael S.T. Vieira submitted a Comment to Solution 3267838

Excellent, Ratul, congrats. And No problem.

3 hours and 38 minutes ago

Rafael S.T. Vieira submitted a Comment to Problem 46963. Roots, Bloody Roots: part 2/2

Hi, Svyatoslav, I've figured out what the problem was. It appears there is a small error < 1e-10 between our interpolation methods. This error wouldn't matter regularly, but since we are doing gamma correction, that error gets magnified. To fix this, I've changed the problem description to request that all interpolations be rounded to 4 decimal places. This seems to resolve the issue (since there will be no error to be magnified by the gamma correction).

3 hours and 53 minutes ago

Rafael S.T. Vieira submitted a Comment to Solution 3314043

If you round both results from linspace to 4 decimal places, this solution will pass the test suite.

3 hours and 55 minutes ago

Rafael S.T. Vieira submitted a Comment to Problem 930. 1D DCT-II transform.

A fair warning to the challenger: the requested DCT-II is the orthogonal version, which means it needs to be multiplied by sqrt(2/N) where N is the size of the row, and the first element of the DCT x0 needs to be multiplied by 1/sqrt(2). It took me a while to understand. Wikipedia's formula is almost right, but it is missing those terms, which are mentioned only further below. Look at MATLAB's documentation (DCT-2), https://www.mathworks.com/help/signal/ref/dct.html, to find the proper formula.

9 hours and 1 minute ago

Rafael S.T. Vieira submitted a Comment to Problem 46833. Roots, Bloody Roots: part 1/2

Svyatoslav Golousov, the real axis pointing left is only a convention. However, I will change the problem description later to explain it as I did on the next one. And I will think of a way to measure the similarity between images. I agree it's essential to provide better feedback; thanks for the suggestion.

9 hours and 1 minute ago

Rafael S.T. Vieira submitted a Comment to Problem 46963. Roots, Bloody Roots: part 2/2

No problem, Svyatoslav, I will take a look tomorrow.

9 hours and 29 minutes ago

Rafael S.T. Vieira liked Problem 45182. Takuzu row

11 hours and 54 minutes ago

Rafael S.T. Vieira submitted Solution 3319398 to Problem 45182. Takuzu row

11 hours and 54 minutes ago

Rafael S.T. Vieira liked Problem 930. 1D DCT-II transform.

14 hours and 20 minutes ago

Rafael S.T. Vieira submitted Solution 3317398 to Problem 930. 1D DCT-II transform.

14 hours and 20 minutes ago

Rafael S.T. Vieira submitted a Comment to Problem 1917. click away

@Alfonso,did you try clicking on the X or red button to close the dialog window from your example?

19 hours and 54 minutes ago

Rafael S.T. Vieira submitted a Comment to Problem 1416. Find the function

It is not easier, Marco. The test suite is filled with noise, and there is no tip on what method to use. Moreover, the last test case goes against what available data provides (which is always monotonically increasing). Even with machine learning, we would not guess the next value using partial and noisy data. If we are trying to classify an animal, but all data is noisy and comes from the animal's tail, it is almost impossible to guess what the animal is. For any new challengers, know that it is a polynomial that you are looking for and it is NOT a line. All test cases have noise, but they all refer to the same polynomial (an even function). The results were taken from the noiseless polynomial, so there is no need to find an exact number (unless you can somehow discover the polynomial).

on 21 Oct 2020 at 4:20

Rafael S.T. Vieira submitted a Comment to Problem 46968. Electric Potential Energy

It seems the problem is actually requesting the electric potential energy instead of the eletric force. Please, fix the test suite or change the name of the problem and its description. https://sciencing.com/calculate-electric-potential-energy-7821281.html

on 20 Oct 2020 at 23:28

Rafael S.T. Vieira submitted Solution 3298173 to Problem 46903. Sudoku

on 20 Oct 2020 at 20:27

Rafael S.T. Vieira submitted Solution 3298163 to Problem 46933. size

on 20 Oct 2020 at 20:27

Rafael S.T. Vieira submitted Solution 3298153 to Problem 46948. area

on 20 Oct 2020 at 20:25

Rafael S.T. Vieira liked Problem 46948. area

on 20 Oct 2020 at 20:24

Rafael S.T. Vieira submitted a Comment to Solution 3267838

No problem. :)

on 20 Oct 2020 at 18:11

Rafael S.T. Vieira submitted a Comment to Solution 3267838

This solution will pass the test suite if you remove the offset of -pi/2, convert values to RGB, and round them to 4 decimal places.

on 20 Oct 2020 at 15:29

Rafael S.T. Vieira submitted a Comment to Problem 46833. Roots, Bloody Roots: part 1/2

All problems are fixed now, sorry Ratul and Alex for any issues that you had. RGB values should be rounded to 4-decimal places. And remove NaNs from your results if present. Let me know if you still experience issues, or if you want a tip (I've fixed some of your codes, and they passed the test suite).

on 20 Oct 2020 at 14:39

Rafael S.T. Vieira submitted a Comment to Problem 46833. Roots, Bloody Roots: part 1/2

Hi, Ratul, yes, you can use hsv2rgb function, but there seems to be a problem with the test suite. Please, wait a while, I will fix everything and update the problem description today.

on 20 Oct 2020 at 13:48

Rafael S.T. Vieira submitted a Comment to Problem 46833. Roots, Bloody Roots: part 1/2

Thanks for the feedback, Alex. (1) The zero angle in the HSV space is given by the color red. So it is positioned on the vertical axis at the figure's center, and the angle increases counter-clockwise. (2) You are right to assume that beta is the euclidean norm, I've checked your solutions for V, and they are correct (as well as S, of course). The problem seems to be with your angle (H). I am not sure you can determine the right angle by using just asin. I believe you need to use atan, or both asin and acos to find the right angle quadrant. (3) You are right. I've forgotten to take into account the noise, sorry about that. When I was designing this problem, I was thinking about using uint8 to remove noise, but in the end, I didn't. So I will fix the test suite to consider only 4 decimal places or use uint8 and update the problem description when I'm finished.

on 20 Oct 2020 at 7:34

Rafael S.T. Vieira submitted a Comment to Problem 1917. click away

@Alfonso And I've read the documentation of drawnow. It is only a refresh function used at several window managers. Since we are not doing animations, I don't see the point. Button's animation is way too small and fast to need a refresh. Even its other task of processing callbacks is doubtful since It may already have occured (and we cannot guaranteee it dind't). A refresh function only tries to guarantee that after it, everything is already done (and it may or may not be blocking), but it does not guarantee that all callbacks weren't executed before (it may have no work to do).

on 19 Oct 2020 at 13:11

Rafael S.T. Vieira submitted a Comment to Problem 1917. click away

@Alfonso, try doing instead 'x=msgbox('Ok'); while ishandle(x), disp('hello word!'); pause(2); end' and you will seen as soon as you click on the button the loop stops. Hope this helps. Your code does not work because as Matlab sees it, it is running the same script in the main thread, and there is no reason why the mouse button should take precedence over an infinite loop following the execution order. However, if we do use threads for instance it would be possible to close the dialog-box despite the existence of an infinite loop. My code works because I made it check the status of the dialog box since it is on the same thread. PS: Funny thing, try to click on the X-button from your message box instead of the Ok-button. Some buttons have different priorities, but the mouse click is being executed either way.

on 19 Oct 2020 at 3:09

Rafael S.T. Vieira submitted a Comment to Problem 2409. Find the Connecting Path

This problem needs to have its description improved. It is not clear why some path must prefered over another like on test case #2. Why the fours must cross at the borders when the sevens didn't? Can we only add one 1 per row? and what's the priority of paths?

on 19 Oct 2020 at 2:18

1 – 50 of 5,756