CALL RANTBL Routine

Returns a random variate from a tabled probability distribution.

Category:	Random Number
Restriction:	This function is not valid on the CAS server.
Note:	Argument types for arguments that are updated must match in CALL routines. All argument types must be CHAR, VARCHAR, or NUMERIC. If the argument types do not match, a warning is issued to the log.

Table of Contents

Syntax

CALL RANTBL(seed, p₁, ...p_i, ...p_n, x);

Required Arguments

seed

is the seed value. A new value for seed is returned each time CALL RANTBL is executed.

Range	seed < 2³¹ - 1
Note	If seed ≤ 0, the time of day is used to initialize the seed stream.
See	Seed Values and Comparison of Seed Values in Random-Number Functions and CALL Routines

p_i

is a numeric SAS value.

Range

0 ≤ p_i ≤ 1 for 0 < i ≤ n

x

is a numeric SAS variable. A new value for the random variate x is returned each time CALL RANTBL is executed.

Details

The CALL RANTBL routine updates seed and returns a variate x generated from the probability mass function defined by p₁ through p_n.

By adjusting the seeds, you can force streams of variates to agree or disagree for some or all of the observations in the same, or in subsequent, DATA steps.

An inverse transform method applied to a RANUNI uniform variate is used. The CALL RANTBL routine returns these data:

StartLayout 1st Row 1st Column Blank 2nd Column StartLayout 1st Row 1st Column 1 2nd Column w i t h p r o b a b i l i t y p 1 EndLayout 2nd Row 1st Column Blank 2nd Column StartLayout 1st Row 1st Column 2 2nd Column w i t h p r o b a b i l i t y p 2 EndLayout 3rd Row 1st Column Blank 2nd Column period 4th Row 1st Column Blank 2nd Column period 5th Row 1st Column Blank 2nd Column period 6th Row 1st Column Blank 2nd Column StartLayout 1st Row 1st Column n 2nd Column w i t h p r o b a b i l i t y p Subscript n EndLayout 7th Row 1st Column Blank 2nd Column StartLayout 1st Row 1st Column n plus 1 2nd Column w i t h p r o b a b i l i t y Baseline 1 minus normal upper Sigma Underscript i equals 1 Overscript n Endscripts p Subscript i Baseline i f normal upper Sigma Underscript i equals 1 Overscript n Endscripts p Subscript i Baseline less-than-or-equal-to 1 EndLayout EndLayout

If, for some index j<n,

multiline equation line 1 normal upper Sigma Underscript i equals 1 Overscript j Endscripts p Subscript i Baseline greater-than-or-equal-to 1

RANTBL returns only the indices 1 through j, with the probability of occurrence of the index j equal to

multiline equation line 1 1 minus normal upper Sigma Underscript i equals 1 Overscript j minus 1 Endscripts p Subscript i

For a discussion and example of an effective use of the random number CALL routines, see Starting, Stopping, and Restarting a Stream.

Comparisons

The CALL RANTBL routine gives greater control of the seed and random number streams than does the RANTBL function.

Example

This example uses the CALL RANTBL routine:

data u1(keep=x);
   seed=104;
   do i=1 to 5;
      call rantbl(seed, .02, x); 
      output;
   end;
   call symputx('seed', seed);
run;
data u2(keep=x);
   seed=&seed;
   do i=1 to 5;
      call rantbl(seed, .02, x); 
      output;
   end;
run;
data all;
   set u1 u2;
   z=rantbl(104, .02);
run;
proc print label;
   label x='Separate Streams' z='Single Stream';
run;

Output from the CALL RANTBL Routine

CALL RANTBL Routine

Syntax

Required Arguments

seed

pi

x

Details

Comparisons

Example

See Also

p_i