Talk:Ulam numbers

timings for the N^th Ulam number

Using the (new and current) REXX program, the times:

It   (the REXX program)   is an   O(2)   polynomial

    0.0000005168509818 N^2  -  0.0004990440614098 N  +  0.5707466809128310
           
    Rsquared = 0.9999999315551220

(The above, as measured and timed on Paul Kislanko's 10-core 8-core PC.       -- Gerard Schildberger (talk) 21:38, 4 December 2020 (UTC)

what, pray tell, is "Paul Kislanko's 10-core PC"? --Pete Lomax (talk) 01:12, 5 December 2020 (UTC)

I made a mistoke, it is an 8-core PC.

By the way,   Paul Kislanko   (an old-timer)   is the proud owner of that fast PC,   and he is gracious enough to run some of my long-running REXX programs on occasion.   With 16 Gbytes and plenty of CPU engines, Paul doesn't even notice what's going on in the back room (or basement?) of his PC.     -- Gerard Schildberger (talk) 02:46, 5 December 2020 (UTC)

Here are the specs:

 OS Name Microsoft Windows 10 Pro
 Version 10.0.19041 Build 19041
 Other OS Description Not Available
 OS Manufacturer Microsoft Corporation
 System Manufacturer LENOVO
 System Model 90L1007AUS
 System Type x64-based PC
 System SKU LENOVO_MT_90L1_BU_LENOVO_FM_IdeaCentre T540-15ICB G
 Processor Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz, 3000 Mhz, 8
 Core(s), 8 Logical Processor(s)
 Installed Physical Memory (RAM) 16.0 GB
 Total Physical Memory 15.9 GB
 Hyper-V - Second Level Address Translation Extensions Yes
 Hyper-V - Virtualization Enabled in Firmware Yes
 Hyper-V - Data Execution Protection Yes

-- Gerard Schildberger (talk) 01:48, 5 December 2020 (UTC)

More info on that 8-core PC:

  The "base" clock speed is 3.00 GHz, but it has a "turbo" mode (overclocking?) or 
  something like that to get to a max of 4.70 GHz.
       
  9th Generation IntelR CoreT i7-9700 Processor with vProT (3.0 GHz, up to
  4.70 GHz with Turbo Boost, 8 Cores, 8 Threads, 12 MB Cache)

So, it's sure is a barn-burner, by gum.   Plus it has a solid-state paging hard-drive (built-in)     -- Gerard Schildberger (talk) 02:46, 5 December 2020 (UTC)

timing for the 100,000^th Ulam number

The total time for the 100,000^th Ulam number using the original REXX program would've taken a little over three years, and that is on Paul Kislanko's PC.     On my old slow PC,   it would've taken about a decade or thereabouts.     -- Gerard Schildberger (talk) 21:22, 4 December 2020 (UTC)

It certainly demonstrates the importance of using a decent algorithm.

Yuppers, ya can say that again.     -- Gerard Schildberger (talk) 21:39, 4 December 2020 (UTC)

I was quite pleased with my first version but it's been trumped twice now by the Phix and XPL0 algorithms! --PureFox (talk) 21:36, 4 December 2020 (UTC)