$ZLN (ObjectScript)

Synopsis

$ZLN(n)

Description

$ZLN returns the natural logarithm (base e) value of n.

Specifying zero or a negative number results in an <ILLEGAL VALUE> error.

A non-numeric string is evaluated as 0 and therefore results in an <ILLEGAL VALUE> error. For evaluation of mixed numeric strings and non-numeric strings, refer to Strings As Numbers.

The corresponding natural logarithm power function is $ZEXP.

Examples

The following example writes the natural log of the integers 1 through 10:

   FOR x=1:1:10 {
     WRITE !,"The natural log of ",x," = ",$ZLN(x) 
     }
   QUIT

returns:

The natural log of 1 = 0
The natural log of 2 = .6931471805599453089
The natural log of 3 = 1.098612288668109691
The natural log of 4 = 1.386294361119890618
The natural log of 5 = 1.609437912434100375
The natural log of 6 = 1.791759469228055002
The natural log of 7 = 1.945910149055313306
The natural log of 8 = 2.079441541679835929
The natural log of 9 = 2.197224577336219384
The natural log of 10 = 2.302585092994045684

The following example shows the relationship between $ZLN and $ZEXP:

   SET x=$ZEXP(1) ; x = 2.718281828459045236
   WRITE $ZLN(x)

returns 1.

   WRITE $ZLN(0)

issues an <ILLEGAL VALUE> error.

See Also

• $ZEXP function

• $ZLOG function

• $ZPI special variable