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ilog2

compute integer base 2 logarithm

ilog10

compute integer base 10 logarithm

ilog[b]

compute integer base b logarithm

 

Calling Sequence

Parameters

Description

Thread Safety

Examples

Calling Sequence

ilog2(x)

 

ilog10(x)

 

ilog[b](x)

ilog[b]x

Parameters

x

-

expression

b

-

positive real number

Description

• 

These functions compute integer approximations to logarithms of x. They are  based on the IEEE function logb.

• 

The ilog[b](x) function approximates the integer base b logarithm, where the default base is exp(1).

• 

You can enter the command ilog[b] using either the 1-D or 2-D calling sequence. For example, ilog[2](50) is equivalent to ilog[2]50.

• 

If x is real, ilog[b](x) returns r such that br|x|<br+1.

• 

The ilog2(x) function returns the integer base 2 logarithm of x.

  

If x is real and r = ilog2(x), then r is either an exact integer or special symbolic value, and 2r|x|<2r+1.

  

If x is a complex numeric, ilog2(x) returns  max(ilog2(Re(x)), ilog2(Im(x))).

  

If x is a special symbolic value, the indicated result is returned.

    1.  ilog2undefined&equals;undefined

    2.  ilog2± =

    3.  ilog2±0 =

• 

The ilog10(x) function returns the integer base 10 logarithm of x.

  

If x is real, ilog10(x) returns r such that r is either an exact integer or special symbolic value, and10r|x|<10r+1.

  

If x is a complex numeric, ilog10(x) returns  max(ilog10(Re(x)), ilog10(Im(x))).

  

If x is a special symbolic value, the indicated result is returned.

    1.  ilog10undefined&equals;undefined

    2.  ilog2± =

    3.  ilog2± =

• 

The computation of ilog2(x) and ilog10(x) is more efficient than ilog[b](x), b <> 2, 10.

Thread Safety

• 

The ilog2 and ilog10 commands are thread-safe as of Maple 15.

• 

For more information on thread safety, see index/threadsafe.

Examples

ilog10x

ilog10x

(1)

ilog10150

2

(2)

ilog101037

37

(3)

ilog10214&plus;310I

4

(4)

ilog250

5

(5)

ilog&lsqb;2&rsqb;28

8

(6)

ilog&lsqb;3&rsqb;10

2

(7)

ilog&lsqb;&ExponentialE;&rsqb;3

1

(8)

See Also

exceptions

float

initialfunctions

type

 


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