The coefficients for bicubic interpolation are given by the function "x^(1/3)"?

Question

Algorithms

I made an interpolator and only after that I looked at what is written on Wikipedia, and something is written there that is too abstruse for me. Some sort of 16-point analysis, continuous polynomials, bi-splines.
But the result of my function is very similar. I don't understand, what's the difference?

Answer 1

difference in accuracy
if you don't need it then what 's the difference

Answer 2

Interpolation by splines is just very simple and obvious.
I wonder what your interpolation algorithm is.
It is not clear from the picture, the code is also not needed - just describe the idea of ​​​​the algorithm.

Answer 3

Didn't check

select
t1.id,
sum(t2.res) as sum_res
from users t1
inner join otvety t2 on t2.id_user = t1.id
inner join voprosy t3 on t3.id = t2.id_vopr
where t3.id_cat = 5
group by t1.id
order by sum_res

Answer 4

The information is not complete about the database schema, what relationships do you have between tables?

SELECT o.id_user FROM vopros v
  INNER JOIN otvet o ON o.id_vopr = v.id
WHERE v.id_cat = "id катег."
GROUP BY v.id 
ORDER BY SUM(o.res)

Answer 5

SELECT `q`.`id_cat`, `a`.`id_user`, SUM(`a`.`res`) AS `res`
  FROM `users` AS `u`
  JOIN `questions` AS `q` 
  LEFT JOIN `answers` AS `a` ON `a`.`id_vopr` = `q`.`id` AND `a`.`id_user` = `u`.`id`
  GROUP BY `q`.`id_cat`, `a`.`user`
  HAVING COUNT(*) = COUNT(`a`.`id_vopr`)