Problem 951. Unique: Faster for options 'rows' and 'stable' for large array of uint8
Challenge: Execute unique(a,'rows','stable') Faster for 'a' being uint8.
The "unique" function for the 'rows' and 'stable' options may be performed 10X more quickly for arrays of large rows, few columns, and uint8 (or values <256).
Input: c=randi(4,6000000,16,'uint8')-1;
Output: unique(c,'rows','stable') or equivalent
Scoring: Time in milli-seconds
Hints:
- unique can sort a single column >10X faster than an array of rows
- 10X improvement is applicable to arrays where rows can be represented as a uint32 value
- 5X improvement occurs where arrays require uint64 representation
Solution Stats
Solution Comments
Show commentsProblem Recent Solvers21
Suggested Problems
-
Return the 3n+1 sequence for n
8227 Solvers
-
Project Euler: Problem 10, Sum of Primes
1691 Solvers
-
Arrange vector in ascending order
769 Solvers
-
Calculate the Hamming distance between two strings
318 Solvers
-
251 Solvers
More from this Author308
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!