FFT Multiplication (HP-48G/GX/G+)

[Raymond Del Tondo]

(02-15-2014 08:26 PM)Gerson W. Barbosa Wrote:  

(02-14-2014 10:37 PM)Raymond Del Tondo Wrote:  

Code:


* Interface  :    [%] [%]'  -->  [%]''

On my HP-48GX (and on the emulator) things go like this: [%] [%]' --> ENTER --> [%]". Is this behavior normal?

No, the stack diagram usually lists the inputs, the way and the output.
The program expects two arrays, and returns another array.

(02-15-2014 08:26 PM)Gerson W. Barbosa Wrote:  Here is the running times table, times in seconds:

Code:


# elements     HP-71B     hp 49g      HP-48GX     hp 50g   48GX(SysRPL)
     16         24.11      10.42         9.96       5.57        4.4  (*)
     32         53.41      22.58        21.91      11.90        9.2
     64        116.74      47.86        47.64      25.16       20.6
    128        269.89     110.14       106.45      47.54       43.6
    256          --       255.87       254.00     104.42       95.4

(*) SysRPL times have been measured with a chronometer because I wasn't able to do it programmatically.

The HP-48GX times have decreased because now I have 54 K RAM free (previously I had only 11 K).

You could use a simple TICKS wrapper, very similar to the tEVAL I use.

Thanks for the correction about the element count. For some reason I thought the example arrays consisted of 128 elements, but it was 64 only. My fault.

So the timings in my last posts actually were for two arrays of 64 elements each.
Still not bad for the brave old HP 48, and still slightly faster than the 50g;-)

Cheers