math:log10

Returns the base-ten logarithm of the argument.

Signature

math:log10($arg as xs:double?) as xs:double?

Properties

This function is deterministic, context-independent, and focus-independent.

Rules

If $arg is the empty sequence, the function returns the empty sequence.

Otherwise the result is the base-10 logarithm of $arg, as defined in the [IEEE 754-2008] specification of the log10 function applied to 64-bit binary floating point values.

Notes

The treatment of divideByZero and invalidOperation exceptions is defined in Arithmetic operators on numeric values. The effect is that if the argument is zero, the result is -INF, and if it is negative, the result is NaN.

Examples

The expression math:log10(()) returns ().

The expression math:log10(0) returns xs:double('-INF').

The expression math:log10(1.0e3) returns 3.0e0.

The expression math:log10(1.0e-3) returns -3.0e0.

The expression math:log10(2) returns 0.3010299956639812e0.

The expression math:log10(-1) returns xs:double('NaN').

The expression math:log10(xs:double('NaN')) returns xs:double('NaN').

The expression math:log10(xs:double('INF')) returns xs:double('INF').

The expression math:log10(xs:double('-INF')) returns xs:double('NaN').