Techniques used in %TILE

FLOOR and CEIL. For an integer, FLOOR and CEIL both return that integer; for a noninteger, FLOOR and CEIL return successive integers that bracket the noninteger.

SORT. The SORT command sorts the list elements into ascending order.

%TILE program listing

 

 

 

 

 

Program:

Comments:

 

 

 

 

«

 

 

SWAP SORT

Brings the list to level 1 and sorts it.

 

DUP SIZE

Copies the list, then finds its size.

 

1 + ROT %

Calculates the position of the specified percentile.

 

DUP2

Makes a copy of the list and the percentile.

 

FLOOR

Rounds the position to the lower integer.

 

1 MAX OVER SIZE MIN

Ensures it is between 1 and the size of the list.

 

GET

Gets the corresponding number.

 

ROT ROT

Moves the list to level 1.

 

CEIL

Rounds the position to the upper integer.

 

1 MAX OVER SIZE MIN

Ensures it is between 1 and the size of the list.

 

GET

Gets the corresponding number.

 

+ 2 /

Calculates the average of the two numbers.

 

»

 

 

 

 

 

`O%TILE K

Stores the program in %TILE.

 

 

 

 

 

Checksum: # 3805d

 

Bytes:

92.5

 

Example: Calculate the median of the list {8 3 1 5 2}. 8 3 1 5 2`

J50 %©TILE%

MEDIAN (Median of Statistics Data)

MEDIAN returns a vector containing the medians of the columns of the statistics data. Note that for a sorted list with an odd number of elements, the median is the value of the center element; for a list with an even number of elements, the median is the average value of the elements just above and below the center.

Level 1

Level 1

 

 

 

 

[ x1 x2  xm ]

 

 

 

RPL Programming Examples 2-11