make-random-state

make-random-state Function

Syntax:

make-random-state &optional state → new-state

Arguments and Values:

state—a random state, or nil, or t. The default is nil.

new-state—a random state object.

Description:

Creates a fresh object of type random-state suitable for use as the value of *random-state*.

If state is a random state object, the new-state is a copy₅ of that object. If state is nil, the new-state is a copy₅ of the current random state. If state is t, the new-state is a fresh random state object that has been randomly initialized by some means.

Examples:

(let\* ((rs1 (make-random-state nil)) 
	(rs2 (make-random-state t)) 
	(rs3 (make-random-state rs2)) 
	(rs4 nil)) 
       (list (loop for i from 1 to 10 
		   collect (random 100) 
		   when (= i 5) 
		   do (setq rs4 (make-random-state))) 
	     (loop for i from 1 to 10 collect (random 100 rs1)) 
	     (loop for i from 1 to 10 collect (random 100 rs2)) 
	     (loop for i from 1 to 10 collect (random 100 rs3)) 
	     (loop for i from 1 to 10 collect (random 100 rs4)))) 
→ ((29 25 72 57 55 68 24 35 54 65) 
   (29 25 72 57 55 68 24 35 54 65) 
   (93 85 53 99 58 62 2 23 23 59) 
   (93 85 53 99 58 62 2 23 23 59) 
   (68 24 35 54 65 54 55 50 59 49)) 

Exceptional Situations:

Should signal an error of type type-error if state is not a random state, or nil, or t.

See Also:

random, *random-state*

Notes:

One important use of make-random-state is to allow the same series of pseudo-random numbers to be generated many times within a single program.

Expanded Reference: make-random-state

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(make-random-state )