Live from HHC2009

[Namir]

Hello All,

We are all here at HP's in Fort Collins, CO. The conference is about to begin!

:-)

Namir

[Johnny Bjoern Rasmussen]

I hope that you'll have a good time.

Cheers!
Johnny

[Walter B]

Enjoy!

And don't forget to tell us the news -- Ft. Collins is far, far away. In addition, economic conditions are a bit worse than last year at that time for whatever cause, the USA as a whole is counted here as "swine flue area", so long range travelling needs very good reasons ;)

[Juan J]

Hello there,

Enjoy and keep us posted.

JuanJ

[Pascal]

Hello Namir, I wish you a good time there ! Greetings from Switzerland.

[Namir]

Thanks Pascal.

The first day was a veyr very long day. We left HP's office at 9:30 pm!! When we got to the hotel we had a second wind and sat in the reception area and chatted some more!

Cheers,

Namir

[Don Shepherd]

Hmmm, sounds like no programming problem contest this year.

[BruceH]

There was one, won by Roger Hill. My effort was hopelessly outclassed (this is what comes of starting it at midnight the night before it was due in). Bill Butler set the challenge - I'll leave him to repost it here when he gets home.

[Jeff O.]

It was specific to the 50G:

HHC 2009 Programming Challenge

Finding partial sums of rows of Pascal's Triangle

         1

        1 1

       1 2 1

      1 3 3 1

     1 4 6 4 1

        etc.

Write an HP50g program which takes a positive integer n of any size in level 2 and any integer r in level 1 and returns the sum of C(n,0) + C(n,1)+...+C(n,r) to level 1. The output should be 0 for r<0 and 2ⁿ for r >= n.

The program will be transferred from your HP50g to the judges' HP50g and will be tested (in exact mode) for a selection of values of n and r chosen by the judges. The fastest program wins.

The usual rules apply:

- The program must be in user code only

- The program must be self-contained

- The program must leave the stack unchanged except for replacing n and r with the result.

- Default flag settings are assumed, except that RPN mode must be set. Flag settings must be restored if changed.

- The judges’ decision is final.

[Don Shepherd]

Thanks Jeff.

[Allen]

FWIW,
I made a smaller binomial sum of products:

http://www.wolframalpha.com/input/?i=sum+%28-1^j%29*binomial%28+n%2Br-2j%2C+r-j%29*binomial%28n%2Br-3j%2Cr-2j%29%2C+j%3D0+to+r%2F2%2C+r%3D13%2C+n%3D8

to satisfy the programming contest.. there's some interesting limitations of it, but should work for all rows under row 30.

It steps through pascals triangle like a knight in a chess board:

I can walk you through the recursion for getting there.. took me about 15 hours without my "Concrete Mathematics" book. The internet wasn't much help either...

Edited: 6 Oct 2009, 8:57 p.m.

[Howard Lazerson]

dont forget to ask when the new enhanced 42s will be available

[Vieira, Luiz C. (Brazil)]

Hi Namir, guys;

congratulations, all of you. Good to know that you, people, are there.

I am not sure if this is common knowledge, but I would like to ask, please, as soon as any online information about the meeting is available, would you let us know? If any already, which links?

Thanks again.

Luiz (Brazil)

[Thomas Chrapkiewicz]

Hello Namir:

Would you be able to post a XL 2003 compatible version of RPN2?

Thanks,
TomC

[Namir]

Tom,

Send me email to:

n.s.h.a.m.m.a.s@aol.com (remove the dots before the @ sign)

I will email you an Excel 2003 version of RPN2.

Regards,

Namir

PS: Thanks for the rides to and from the conference!

Edited: 5 Oct 2009, 9:28 p.m.

[Thomas Chrapkiewicz]

Namir:

Thank you. It was a great pleasure spending time with you at the conference! Hope to see you again next time!

TomC