XPATH math:log

log

Signature

 xsd:double  LOG (numeric)

The result is the mathematical constant e raised to the power of $arg, as defined in the [IEEE 754-2008] specification of the log function applied to 64-bit binary floating point values.

This function is equivalent to as math:log.

ASK {FILTER(LOG(EXP(1)) = "1.0e0"^^xsd:double)}
ASK {FILTER(LOG(1.0e-3) = "-6.907755278982137e0"^^xsd:double)}
ASK {FILTER(LOG(2) = "0.6931471805599453e0"^^xsd:double)}

Should return true

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

log() 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?