Very Computer

I have CPI (Consumer price index) series
with the year before as a base.
(change in prices from the preceeding year)
for example :
1999 100
2000 101
2001  99
2002  85
2003 120

And i want to translate it in cumulated series.
CPI with a base period in 1999.
So i have got to multiplicate 1-with-2, 1-with-2-with-3,
and so on ...
so it is :
1999 100
2000 101
2001  99,9
2002  84,9
2003 101,9

How to do it in the simplest way in SAS ??
(Not using ln aproximation :-) )

Tnx,

Pawel Manowiecki
SAS Student

On Tue, 18 Jun 2002 15:24:15 -0700, Pawel Manowiecki

This seems to be a good candidate for set point option:

data xx;
input year cpi;
cards;
1999 100
2000 101
2001  99
2002  85
2003 120
;

data xx;
do i=1 to nobs;
 ncpi=1;
 do j=1 to i;
 set xx nobs=nobs point=j;
 ncpi=ncpi*cpi;
 end;
 output;
end;
stop;

proc print;
run;

----------------
Obs    i           ncpi    year    cpi

 1     1            100    1999    100
 2     2          10100    2000    101
 3     3         999900    2001     99
 4     4       84991500    2002     85
 5     5    10198980000    2003    120

Is this what you want? The first few digits seem to match your
result, not sure if I need some rounding.

HTH

Ya Huang

I think this will do the job:
data cpinew;
  set cpiold;
  retain cpicum 1;
  cpicum=cpicum*cpi;
run;

Stig Eide

Hi Pawel,

Here s a simple solution:

data cpiold;
   input year cpi;
cards;
1999 100
2000 101
2001  99
2002  85
2003 120
;
run;

data cpinew;
  set cpiold;
  retain cpicum 1;
  i+1;
  cpicum=cpicum*cpi;
  cpiround=cpicum/100**(i-1);
  put cpicum= cpiround=;
run;

Xavier Autret

Ya,

This will work, however bear in mind that you will have to directly read
about 0.5*N**2 records. Such a scheme will quickly become prohibitively
expensive: already at N=10000 (not a large file by any stretch of fancy),
you will have to read 50 million records directly (and out of sequence and
hence rebuffering at each i-loop iteration unless SASFILE is used - granted,
with N=10000 it is a distinct possibility). Thus single-pass approaches make
more performance sense, all the more that, as you of course realize, no
cumulative amount has to be recomputed from the beginning of the chain each
time a new link is acquired.

Now if I get what Pawel wants correctly, I would venture to offer:

data cpi ;
   input year cpi ;
cards ;
1999 100
2000 101
2001  99
2002  85
2003 120
;
run;

data cumcpi ( keep = year cpi cumcpi ) ;
  retain prod 1 mult 1000 ;
  set cpi ;
  mult   = mult * 0.01 ;
  prod   = prod * cpi  ;
  cumcpi =  0.1 * int (prod * mult) ;
  put cpi= cumcpi= ;
run ;

SAS log prints:

cpi=100 cumcpi=100
cpi=101 cumcpi=101
cpi=99 cumcpi=99.9
cpi=85 cumcpi=84.9
cpi=120 cumcpi=101.9

Kind regards,
==================
Paul M. Dorfman
Jacksonville, FL
==================

Blue Cross Blue Shield of Florida, Inc., and its subsidiary and
affiliate companies are not responsible for errors or omissions in this e-mail message. Any personal comments made in this e-mail do not reflect the views of Blue Cross Blue Shield of Florida, Inc.

Quote:> Now if I get what Pawel wants correctly, I would venture to offer:

> data cpi ;
>    input year cpi ;
> cards ;
> 1999 100
> 2000 101
> 2001  99
> 2002  85
> 2003 120
> ;
> run;

> data cumcpi ( keep = year cpi cumcpi ) ;
>   retain prod 1 mult 1000 ;
>   set cpi ;
>   mult   = mult * 0.01 ;
>   prod   = prod * cpi  ;
>   cumcpi =  0.1 * int (prod * mult) ;
>   put cpi= cumcpi= ;
> run ;

Or, equivalently using a DOW loop

data cumcpi ( keep = year cpi cumcpi ) ;
  prod=1;
  mult=1000 ;
  do until (lastrec);
    set cpi end=lastrec;
    mult   = mult * 0.01 ;
    prod   = prod * cpi  ;
    cumcpi =  0.1 * int (prod * mult) ;
    put cpi= cumcpi= ;
    output;
  end;
run ;

Dale

=====
---------------------------------------
Dale McLerran
Fred Hutchinson Cancer Research Center

Ph:  (206) 667-2926
Fax: (206) 667-5977
---------------------------------------

__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com

Dale,

I am not sure what is the benefit of explicit looping in this case...
however, on the second thought, it could allow for saving a couple of
auxiliary variables :-)

data cumcpi ;
   do _iorc_ = 1000 by 0 ;
      set cpi ;
      _iorc_ = _iorc_ * 0.01 ;
      _n_    = _n_    * cpi  ;
      cumcpi =  0.1 * int (_n_ * _iorc_) ;
      put cpi= cumcpi= ;
      output ;
   end ;
run ;

Kind regards,
==================
Paul M. Dorfman
Jacksonville, FL
==================

Blue Cross Blue Shield of Florida, Inc., and its subsidiary and
affiliate companies are not responsible for errors or omissions in this e-mail message. Any personal comments made in this e-mail do not reflect the views of Blue Cross Blue Shield of Florida, Inc.