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Library: Floating point number support (OMFLOAT)
Import : omfloat.xmd Library: Binary coded decimal numbers (OMBCD) Import : ombcd.xmd |
Returns: The logarithm base ten for a bcd or a floating point number. The value of x must be greater than 0. |
define overloaded external float function log10 value float x define overloaded external bcd function log10 value bcd x
Use log10 to calculate the logarithm base ten of:
You must import either ombcd.xmd or omfloat.xmd in your program. Decide whether you want BCD mathematics (excellent for financial calculations) or floating point mathematics (excellent for extremely large numbers).
; Displays the base-10 logarithm of 100 as a floating point number. import "omfloat.xmd" unprefixed process local float x initial {"100"} local float result set result to log10 (x) output "Logarithm (base 10) of " || "d" % x || " = " || "d" % result || "%n" ; Output: "Logarithm (base 10) of 100 = 2".
; How to multiply BCD numbers by adding their base 10 logarithms. import "ombcd.xmd" unprefixed process local bcd x-var initial {"100"} local bcd y-var initial {"50"} local bcd log10-x local bcd log10-y local bcd x-times-y local bcd logarithm-total set log10-x to log10 (x-var) output "Logarithm (base 10) of " || "d" % x-var || " = " || "d" % log10-x || "%n" ; Output: "Logarithm (base 10) of 100 = 2". set log10-y to log10 (y-var) output "Logarithm (base 10) of " || "d" % y-var || " = " || "d" % log10-y || "%n" ; Output: "Logarithm (base 10) of 50 = 1.6989700043360182". set logarithm-total to log10-x + log10-y set x-times-y to 10 ** logarithm-total output "100 times 50 by adding logarithms = " || "d" % x-times-y || "%n" ; Output: "100 times 50 by adding logarithms = 4999.999999999992".
If the result of a logarithm (base 10) does not fit in the data type of the argument, the value returned is truncated to fit the data type.
If you calculate the natural logarithm of an integer, you need to coerce the integer - to a floating point or BCD number - so that the appropriate function is called. The result will depend on which logarithm function is called.
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