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 Solvers20
Suggested Problems
-
94998 Solvers
-
Number of 1s in the Binary Representation of a Number
439 Solvers
-
Flip the main diagonal of a matrix
780 Solvers
-
854 Solvers
-
Construct an index vector from two input vectors in vectorized fashion
374 Solvers
More from this Author294
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!