ln() computes natural logarithm, lg() computes base 10 logarithm, and
lb() computes binary (base 2) logarithm.
ln1p() and lg1p() computes ln(x + 1) and lg(x + 1) accurately also
for |x| << 1.
E is the Euler constant and is equal to exp(1).
Details
Those functions are synonyms of log(), log10(), log2(),
log1p() for those who prefer the shorter notation. Beginners sometimes
make confusion between log() and log10(). Using ln() for natural
logarithms instead of log() eliminates this confusion. E is provided for
convenience as exp(1), although the use of exp() is usually familiar
enough to everyone.
Examples
ln(exp(3)) # Same as log(exp(3))
#> [1] 3
lg(10^3) # Same as log10(10^3)
#> [1] 3
lb(1:3) # Wrapper for log2()
#> [1] 0.000000 1.000000 1.584963
ln1p(c(0, 1, 10, 100)) # Wrapper for log1p()
#> [1] 0.0000000 0.6931472 2.3978953 4.6151205
lg1p(c(0, 1, 10, 100)) # log10(x + 1), but optimized for x << 1
#> [1] 0.000000 0.301030 1.041393 2.004321
E^4 # Similar to exp(4), but different calculation!
#> [1] 54.59815