Update autotune.md

Author: ChrisRackauckas

docs/src/tutorials/autotune.md

@@ -73,7 +73,7 @@ Control which matrix size ranges to test:
 # :small  - 20×20 to 100×100 (small problems)  
 # :medium - 100×100 to 300×300 (typical problems)
 # :large  - 300×300 to 1000×1000 (larger problems)
-# :big    - 10000×10000 to 100000×100000 (GPU/HPC scale)
+# :big    - 10000×1000 to 20000x20000 (GPU/HPC scale)
 
 # Default: test tiny through large
 results = autotune_setup()  # uses [:tiny, :small, :medium, :large]
@@ -449,4 +449,4 @@ LinearSolveAutotune provides a comprehensive system for benchmarking and optimiz
 - Performance visualization
 - Preference setting for automatic algorithm selection (in development)
 
-By running autotune and optionally sharing your results, you help improve LinearSolve.jl's performance for everyone in the Julia community.
+By running autotune and optionally sharing your results, you help improve LinearSolve.jl's performance for everyone in the Julia community.