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As of October, 2016, Embarcadero is offering a free release of Delphi (Delphi 10.1 Berlin Starter Edition ).     There are a few restrictions, but it is a welcome step toward making more programmers aware of the joys of Delphi.  They do say "Offer may be withdrawn at any time", so don't delay if you want to check it out.  Please use the feedback link to let me know if the link stops working.

 

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Random Number Generators have been studied extensively during the computer age and a large body of documentation exists. Delphi's Random function is limited to 32 bits, about 4 billion.    When I had a need for random integers up to 300 billion recently, I thought that finding a 64 bit Delphi or Pascal version would be simple.   There are plenty of C-whatever examples, but not so many on our side of the fence. 

I ended up installing two versions into our MathsLib unit.

For Delphi versions after D7, I used the Random64 function by J.R Stockton found at http://www.merlyn.demon.co.uk/programs/mathutys.pas.  It uses the unsigned 64 bit integer type UInt64, and so cannot be used in D7 and earlier versions.  For those compilers I wrote a Random64 function which converts a passed Int64 integer to  a TInteger big integer type and pass that to the Random procedure in our UBigIntsV4 unit.  The returned value is converted back to an Int64 type and returned to the caller.

I plan to do more statistical testing of these functions and perhaps locate or develop a function that will work for both early and later Delphi versions.  Windows has a native "CryptGenRandom" function if I find the appropriate API to allow Delphi to use it. 

The current routines are located    

 

Links to Explore

  http://www.freepascal.org/docs-html/rtl/system/random.html             
  http://www.tek-tips.com/faqs.cfm?fid=7590
  http://www.merlyn.demon.co.uk/programs/mathutys.pas
  http://www.delphitools.info/2011/12/13/pimp-your-random-numbers-with-xorshift/
 

 Running/Exploring the Program 

 

Created August 13, 2013

Modified February 18, 2016

 

 

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