Date:         Wed, 7 May 2003 16:09:57 -0400
Reply-To:     Howard Schreier <Howard_Schreier@ITA.DOC.GOV>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Howard Schreier <Howard_Schreier@ITA.DOC.GOV>
Subject:      Re: Difference between INT and FLOOR functions?

And to make life a bit more interesting, the corresponding functions in
Excel work differently.

The SAS INT function displays a symmetry: INT(-x) = -INT(x). NoOt so in
Excel, where INT(-1.2) = -2.

The Excel CEILING and FLOOR functions each take a second argument
(called "Significance") to allow for non-unity multiples. For example,
CEILING(1.5,0.4) = 1.6. Excel is unhappy if the two arguments have
different signs. I modeled the single-argument SAS functions CEIL and FLOOR
in Excel as

   CEILING(x,SIGN(x))

and

   FLOOR(x,SIGN(x))

For x = -1.2, CEILING returns -2 and FLOOR returns -1. In other words, for
these functions it is Excel which displays symmetry and SAS which does not.

I became really aware of this once when I was trying to use Excel to
develop a formula fragment which I intended to use in SAS.

On Tue, 6 May 2003 20:30:08 -0400, Mark Lamias <Mark.Lamias@GRIZZARD.COM>
wrote:

>Barb,
>
>From one Wolverine to another -- GO BLUE!.
>
>The FLOOR function "Returns the largest integer that is less than or equal
>to the argument" which the INT function returns the integer part of the
>argument.
>
>This can best be seen by using an example with a negative number passed to
>both arguments:
>
>data _null_;
>x=-9.4;
>y=floor(x);
>z=int(x);
>put 'floor ' y;
>put 'int '  x;
>run;
>
>This produces the following:
>
>floor -10
>int -9
>
>If the argument is positive, both floor and int return the same results.
>
>Sincerely yours,
>
>Mark J. Lamias
>Statistical Consultant
>
>
>
>
>-----Original Message-----
>From: Barb Smith [mailto:brksmith@HOTMAIL.COM]
>Sent: Tuesday, May 06, 2003 7:17 PM
>To: SAS-L@LISTSERV.UGA.EDU
>Subject: Difference between INT and FLOOR functions?
>
>
>Hi all,
>
>I am putting together a list of common functions,
>what they do, and examples of how they work.
>
>I hope to present this as a poster or short
>presentation at the next SUGI (if the University
>allows me to do"international" travel).
>
>The two functions that I see no difference between are
>INT and FLOOR.  Can someone help me understand when
>these two functions would return different results?
>
>Also, can anyone explain why the number
>Y = 4.99999999999999991 shows up in the
>data as 5.0000000000000000000000000000?
>
>Thanks so much for any help you can offer!
>
>Barb Smith
>Senior Programmer Analyst
>University of Michigan
>
>---------------------------------------------------
>Here is the program I used:
>
>data work.temp;
>format y 30.28;
>input y;
>cards;
>4.99999999999999991
>4.9999999999999991
>4.999999999999991
>4.99999999999991
>4.9999999999991
>4.999999999991
>4.99999999991
>4.9999999991
>4.999999991
>4.99999991
>4.9999991
>4.999991
>4.99991
>4.9991
>4.991
>4.91
>4.1
>;
>run;
>
>data work.temp2;
>set work.temp;
>x1=int(y);
>x2=ceil(y);
>x3=floor(y);
>x4=fuzz(y);
>run;
>
>-----------------------------------------------------
>Here is the work.temp2 table:
>
>             y                   |  x1   |  x2   |  x3   |  x4          |
>5.0000000000000000000000000000   |   5   |   5   |   5   |   5
>5.0000000000000000000000000000   |   5   |   5   |   5   |   5
>4.9999999999999900000000000000   |   5   |   5   |   5   |   5
>4.9999999999999100000000000000   |   5   |   5   |   5   |   5
>4.9999999999991000000000000000   |   5   |   5   |   5   |   5
>4.9999999999910000000000000000   |   4   |   5   |   4   |   5
>4.9999999999100000000000000000   |   4   |   5   |   4   |   4.9999999999
>4.9999999991000000000000000000   |   4   |   5   |   4   |   4.9999999991
>4.9999999910000000000000000000   |   4   |   5   |   4   |   4.999999991
>4.9999999100000000000000000000   |   4   |   5   |   4   |   4.99999991
>4.9999991000000000000000000000   |   4   |   5   |   4   |   4.9999991
>4.9999910000000000000000000000   |   4   |   5   |   4   |   4.999991
>4.9999100000000000000000000000   |   4   |   5   |   4   |   4.99991
>4.9991000000000000000000000000   |   4   |   5   |   4   |   4.9991
>4.9910000000000000000000000000   |   4   |   5   |   4   |   4.991
>4.9100000000000000000000000000   |   4   |   5   |   4   |   4.91
>4.1000000000000000000000000000   |   4   |   5   |   4   |   4.1
>
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