[]NULL

[giangiquario]

Version: 13.0.16306.1 32 Classic
Created: Jan 14 2013 at 19:36:46
Build ID: c169c6f1

When dealing with scalar []NULL, I noticed that:

Code: Select all

]cpu '200 200⍴⎕null'

* Benchmarking "200 200⍴⎕null"
             Exp 
 CPU (avg):    0 
 Elapsed:      0 

      ]cpu '200 200↑⎕null'

* Benchmarking "200 200↑⎕null"
               Exp 
 CPU (avg):  15179 
 Elapsed:    15179

[JohnS|Dyalog]

Hi Gianluigi,
The overtake is creating new instances of the structure we use to represent ⎕NULL, whereas the reshape is just duplicating a pointer. I have logged an RFE (request for enhancement) ref [9126] to address this performance issue.
Thanks for taking the time to report it.
John.