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|
;+
; NAME:
; RANDOMNUMBERGENERATOR
;
; PURPOSE:
;
; Allows the user to obtain a sequence of pseudo-random numbers. The
; object maintains the random number generator seed in such a way that
; subsequent calls to GetRandomNumbers will guarentee that you don't
; get the same random numbers each time you ask for random numbers.
;
; AUTHOR:
;
; FANNING SOFTWARE CONSULTING
; David Fanning, Ph.D.
; 1645 Sheely Drive
; Fort Collins, CO 80526 USA
; Phone: 970-221-0438
; E-mail: david@idlcoyote.com
; Coyote's Guide to IDL Programming: http://www.idlcoyote.com
;
; CATEGORY:
; Utilities
;
; CALLING SEQUENCE:
;
; Generate three random numbers.
;
; IDL> rng = Obj_New('RandomNumberGenerator', initialSeed)
; IDL> numberOfNumbersNeeded = 3
; IDL> randomNumbers = rng -> GetRandomNumbers(numberOfNumbersNeeded)
; IDL> Print, randomNumbers
; 0.80952855 0.35878432 0.52150406
;
; Generate a sequence of 8 random digits.
; IDL> Print, rng -> GetRandomDigits(8)
; 21855786
;
; INPUT PARAMETERS FOR INIT METHOD:
;
; initialSeed: The initial seed for the random number generator. If undefined
; or absent, the number of seconds after 1 January 1970 is used.
;
; METHODS:
;
; randomNumbers -> GetRandomNumbers(d1, d2, d3, d4 d5, d6, d7, d8)
; randomDigits = obj -> GetRandomDigits(numDigets)
; obj -> SetSeed, seed
;
; MODIFICATION HISTORY:
;
; Written by David W. Fanning, 13 November 2009.
; Added GetRandomDigits method. 7 February 2010. DWF.
; Incorrect cleanup of the seed pointer fixed in the CLEANUP procedure.
; 25 February 2010, DWF.
;-
;******************************************************************************************;
; Copyright (c) 2009-2010, by Fanning Software Consulting, Inc. ;
; All rights reserved. ;
; ;
; Redistribution and use in source and binary forms, with or without ;
; modification, are permitted provided that the following conditions are met: ;
; ;
; * Redistributions of source code must retain the above copyright ;
; notice, this list of conditions and the following disclaimer. ;
; * Redistributions in binary form must reproduce the above copyright ;
; notice, this list of conditions and the following disclaimer in the ;
; documentation and/or other materials provided with the distribution. ;
; * Neither the name of Fanning Software Consulting, Inc. nor the names of its ;
; contributors may be used to endorse or promote products derived from this ;
; software without specific prior written permission. ;
; ;
; THIS SOFTWARE IS PROVIDED BY FANNING SOFTWARE CONSULTING, INC. ''AS IS'' AND ANY ;
; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES ;
; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT ;
; SHALL FANNING SOFTWARE CONSULTING, INC. BE LIABLE FOR ANY DIRECT, INDIRECT, ;
; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED ;
; TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; ;
; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ;
; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ;
; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ;
; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ;
;******************************************************************************************;
;------------------------------------------------------------------------------------------;
; NAME:
; RandomNumberGenerator::GetRandomDigits
;
; Purpose:
;
; Allows the user to obtain a string variable of random digits.
;
; Method Syntax:
;
; randomDigits = obj -> GetRandomDigits(numberOfDigits)
;
; Auguments:
;
; numberOfDigits: The number of digits desired. (Input, default is 8. )
;
; Keywords:
;
; BYTES: If this keyword is set, the random digits are returned
; as a byte array, rather than as a string.
;
; Return Value:
;
; randomDigits: A string variable containing the random digits.
;
;------------------------------------------------------------------------------------------;
FUNCTION RandomNumberGenerator::GetRandomDigits, digits, BYTES=bytes
COMPILE_OPT idl2
On_Error, 2
; Default is 8 digits.
IF N_Elements(digits) EQ 0 THEN digits = 8
; How many random numbers are needed to construct this number of digits?
numbersNeeded = Long( digits/16 ) + 1
; Get the numbers and use only the digits after the "0.".
randomNumbers = self -> GetRandomNumbers(numbersNeeded, /DOUBLE)
strNumbers = StrMid(String(randomNumbers, FORMAT='(F18.16)'), 2)
; Put the digits together to come up with the correct number.
digitNumbers = strNumbers[0]
FOR j=1,N_Elements(randomNumbers)-1 DO digitNumbers = digitNumbers + strNumbers[j]
; Trim the result to the correct number of digits.
IF StrLen(digitNumbers) GT digits THEN digitNumbers = StrMid(digitNumbers,0,digits)
; Do you need bytes instead of a string?
IF Keyword_Set(bytes) THEN BEGIN
numbers = BytArr(digits)
FOR j=0,digits-1 DO BEGIN
numbers[j] = Byte(Fix(StrMid(digitNumbers, j, 1)))
ENDFOR
digitNumbers = numbers
ENDIF
;Return the digits you need.
RETURN, digitNumbers
END
;------------------------------------------------------------------------------------------;
; NAME:
; RandomNumberGenerator::GetRandomNumbers
;
; Purpose:
;
; Allows the user to obtain a scalar or array of random numbers.
;
; Method Syntax:
;
; randomNumbers = obj -> GetRandomNumbers(d1, d2, d3, d4, d5, d6, d7, d8)
;
; Auguments:
;
; d1...d8 Up to 8 dimension values can be specified, as in the IDL on-line
; documentation for RANDOMU.
; Keywords:
;
; All the keywords that are defined for the IDL built-in routine RANDOMU are
; available for use here. The only difference is that non-integer numbers are
; *always* returned as double-precision values. That is to say DOUBLE is always
; set to 1. See the IDL on-line documentation for RANDOMU to understand how to use
; the following keywords:
; BINOMIAL
; DOUBLE
; GAMMA
; NORMAL
; POISSON
; UNIFORM
; LONG
;
; Return Value:
;
; randomNumbers: The scalar or array of random numbers.
;
;------------------------------------------------------------------------------------------;
FUNCTION RandomNumberGenerator::GetRandomNumbers, d1, d2, d3, d4, d5, d6, d7, d8, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long
; I just assume any floating value is *suppose* to be in double precision.
IF N_Elements(double) EQ 0 THEN double = 1
; Yuck! Have to do this according to the number of positional parameters.
CASE N_Params() OF
0: results = RandomU(*self.seed, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
1: results = RandomU(*self.seed, d1, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
2: results = RandomU(*self.seed, d1, d2, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
3: results = RandomU(*self.seed, d1, d2, d3, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
4: results = RandomU(*self.seed, d1, d2, d3, d4, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
5: results = RandomU(*self.seed, d1, d2, d3, d4, d5, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
6: results = RandomU(*self.seed, d1, d2, d3, d4, d5, d6, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
7: results = RandomU(*self.seed, d1, d2, d3, d4, d5, d6, d7, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
8: results = RandomU(*self.seed, d1, d2, d3, d4, d5, d6, d7, d8, $
BINOMIAL=binomial, $
DOUBLE=double, $
GAMMA=gamma, $
NORMAL=normal, $
POISSON=poisson, $
UNIFORM=uniform, $
LONG=long)
ENDCASE
; Return the results.
RETURN, results
END ;----------------------------------------------------------------
PRO RandomNumberGenerator::SetSeed, theSeed
; Sets the seed for the random number generator.
IF N_Elements(theSeed) NE 0 THEN *self.seed = theSeed
END ;----------------------------------------------------------------
PRO RandomNumberGenerator::CLEANUP
Ptr_Free, self.seed
END ;----------------------------------------------------------------
FUNCTION RandomNumberGenerator::INIT, initialSeed
; Initializes the random number generator. The initialSeed is the initial
; seed for the generator. If absent, the number of seconds after 1 January 1970
; is used as the seed.
Catch, theError
IF theError NE 0 THEN BEGIN
Catch, /CANCEL
Help, /Last_Message
Return, 0
ENDIF
; Initialize the pointer.
self.seed = Ptr_New(/ALLOCATE_HEAP)
; Create the initial seed, if needed. Otherwise, just store it.
IF N_Elements(initialSeed) EQ 0 $
THEN self -> SetSeed, Systime(1) $
ELSE self -> SetSeed, initialSeed
RETURN, 1
END ;----------------------------------------------------------------
PRO RandomNumberGenerator__Define
class = { RANDOMNUMBERGENERATOR, $
seed: Ptr_New() }
END ;----------------------------------------------------------------
|
