XPATH math:log10

log10

Signature

 xsd:double  LOG10 (numeric)

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.

This function is a close equivalent of math:exp.

ASK {FILTER(log10(1.0e3) = "3.0e0"^^xsd:double)}
ASK {FILTER(log10(1.0e-3) = "-3.0e0"^^xsd:double)}
ASK {FILTER(log10(2) = "0.3010299956639812e0"^^xsd:double)}

Should return true

log10() called without a variable/value should be a parse error.

log10() cast with a numeric should have an attempted cast to the xsd:double.

TODO

Error values => 0, Infinity, what happens if a non numeric is given as an argument? UNDEF or error?