com.logspace {compoisson} | R Documentation |
Computes the difference of two values in log-space.
com.log.difference(x, y) com.log.sum(x, y) com.log.factorial(x)
x |
first value |
y |
second value |
com.log.difference
computes the difference of two values in log-space, log( e^x - e^y ),
without significant chance of overflow or underflow.
com.log.sum
computes the sum of two values in log-space, log( e^x + e^y ), without
significant change of overflow or underflow.
com.log.factorial
computes log(x!) which is equivalent to a summation.
The requested computation in log-space.
Jeffrey Dunn
a = exp(com.log.difference(log(100), log(20))); # a = 80 b = exp(com.log.sum(log(100), log(20))); # b = 120 c = exp(com.log.factorial(4)); # c = 24