Microsoft KB Archive/86523

= Random Number Generation =

Article ID: 86523

Article Last Modified on 11/16/2006

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APPLIES TO


 * Microsoft Excel 97 Standard Edition
 * Microsoft Excel 95 Standard Edition
 * Microsoft Excel 5.0 Standard Edition
 * Microsoft Excel 98 for Macintosh

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This article was previously published under Q86523



SUMMARY
In Microsoft Excel, the RAND function uses the following iterative method to calculate pseudo-random numbers:

The first random number:

  random_number=fractional part of (9821 * r + 0.211327), where r = .5

Successive random numbers:

  random_number=fractional part of (9821 * r + 0.211327), where r = the previous random number

This formula will provide up to 1 million different numbers.



MORE INFORMATION
Computers cannot generate truly random numbers. Instead, they return a series of numbers based on a mathematical relationship that simulates &quot;randomness.&quot; The &quot;randomness&quot; exhibited by the numbers is a function of the mathematical formula used by the random number generator.

In Microsoft Excel for Windows, adding randomize=1 to the [Microsoft Excel] section of the appropriate .INI file for your version of Microsoft Excel will cause &quot;r&quot; to be determined from the system clock (which adds a further degree of randomness to the numbers generated).

  For this version         The name of your of Microsoft Excel      .INI file is this -

5.0                     EXCEL5.INI 4.0                     EXCEL4.INI 3.0                     EXCEL.INI

Note that there is no such setting with Microsoft Excel for OS/2 or Microsoft Excel for the Macintosh.

NOTE: Excel 5.0 defaults to the RANDOMIZE=1 setting. Previous versions of Microsoft Excel defaulted to RANDOMIZE=0.

Additional query words: 1.0 1.00 1.03 1.04 1.06 1.5 1.50 2.0 2.00 2.01 2.1 2.10 2.2 2.20 2.21 3.0 3.00 4.0 4.00 rand random algorithm Excel

Keywords: kbinfo KB86523

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