log Natural logarithm &reftitle.description; floatlog floatarg floatbaseM_E If the optional base parameter is specified, log returns logbase arg, otherwise log returns the natural logarithm of arg. &reftitle.parameters; arg The value to calculate the logarithm for base The optional logarithmic base to use (defaults to 'e' and so to the natural logarithm). &reftitle.returnvalues; The logarithm of arg to base, if given, or the natural logarithm. &reftitle.changelog; &Version; &Description; 4.3.0 The optional parameter base became available. For older versions you can calculate the logarithm in base b of a number n, but using the mathematical identity: logb(n) = log(n)/log(b), where log is the neperian (or natural) logarithm. &reftitle.seealso; log10 exp pow