Difference between revisions of "Delphi compatible LCG Random"
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Jump to navigationJump to search| Line 14: | Line 14: | ||
interface | interface | ||
| − | function DelphiRandom: | + | function DelphiRandom: extended; overload;inline; |
function DelphiRandom(range:longint):longint;overload;inline; | function DelphiRandom(range:longint):longint;overload;inline; | ||
| Line 25: | Line 25: | ||
end; | end; | ||
| − | function DelphiRandom: | + | function DelphiRandom: extended; overload;inline; |
begin | begin | ||
Result := IM * 2.32830643653870e-10; | Result := IM * 2.32830643653870e-10; | ||
Revision as of 16:01, 26 March 2017
Delphi compatible random numbers
Many Freepascal programmers also maintain sourcecode in Delphi.
Even if you have moved to Freepascal from Delphi you may have data that relies on Delphi's Random.
Here are cross-platform functions that generate Delphi-identical pseudo-random numbers:
unit drandom;
// Delphi compatible LCG random number generator routines for Freepascal.
// (c)2017, Thaddy de Koning. Use as you like
// Algorithm, Delphi multiplier and increment taken from:
// https://en.wikipedia.org/wiki/Linear_congruential_generator
// The default Delphi RandomSeed is determined as zero.
{$mode objfpc}
interface
function DelphiRandom: extended; overload;inline;
function DelphiRandom(range:longint):longint;overload;inline;
implementation
function IM:cardinal;inline;
begin
RandSeed := RandSeed * 134775813 + 1;
Result := RandSeed;
end;
function DelphiRandom: extended; overload;inline;
begin
Result := IM * 2.32830643653870e-10;
end;
function DelphiRandom(range:longint):longint;overload;inline;
begin
Result := IM * range shr 32;
end;
end.