In hannahdxz/powers: simple computation of powers

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powers

The goal of the powers package is to perform basic computations on numerical vectors.

This package has four exported functions: square(), cube(), box_cox() and my_log(). There is one internal function pow() which these four functions depend on.

These four functions only work for numerical input. When the input is of other type, an "invalid input" message will be returned.

Description & Examples

In this section I will explain the arguments of each function and give some examples for each function.

First, load my powers package.

library(powers)

(1) The function square(x,na.omit) squares a vector.

x is the vector to be squared.
na.omit is whether or not to remove NAs, the default is FALSE.

num_vec <- c(0, -4.6, 3.4, NA)
square(num_vec)

square(num_vec, na.omit=TRUE)

num_vec2 <- c(0, -4.6, 3.4, "a")
square(num_vec2)

(2) The functioncube(x,na.omit) raises a vector to the power of 3.

x is the vector to be cubed.
na.omit is whether or not to remove NAs, the default is FALSE.

num_vec <- c(0, -4.6, 3.4, NA)
cube(num_vec)

cube(num_vec, na.omit=TRUE)

num_vec2 <- c(0, -4.6, 3.4, "a")
cube(num_vec2)

(3) The functionbox_cox(y, lambda1, lambda2, na.omit) calculate the box cox transform of a vector. Here is the formula of the transformation: cox box (formula source: wikipedia)

y is the vector to be transformed.
lambda1 is the first parameter of the transformation, range from -5 to 5.
lambda2 is the second parameter of the transformation, lambda2 is introduced for negative values of y, it must be greater than -y.
na.omit is whether or not to remove NAs, the default is FALSE.

num_vec <- c(0, -4.6, 3.4, NA)
box_cox(num_vec,4,6) # not omit NA

box_cox(num_vec,4,6,na.omit=TRUE) # omit NA

box_cox(num_vec,4,2,na.omit=TRUE) # lambda2 too small

box_cox(num_vec,6,2,na.omit=TRUE) # lambda1 >5

num_vec2 <- c(0, -4.6, 3.4, "a")
box_cox(num_vec2,4,6)

(4) The functionmy_log(x,base=exp(1),na.omit=FALSE) perform log transformation.

x is the vector to be transformed. x>=0
base is the base of the log transformation, the default is exp(1)
na.omit is whether or not to remove NAs, the default is FALSE.
Note: This function can only calculate the log transformation of x in the range: base^(-100) <= x <= base^100

my_log(exp(7))
num_vec <- c(0, 8,64,NA)
my_log(num_vec,2) # not omit NA

my_log(num_vec,2, na.omit = TRUE) # omit NA

num_vec1 <- c(0, 4.6, 900000000000000000)
my_log(num_vec1,1.5) # can not calculate x > base^100

my_log(-10,2) # x can not be negative

num_vec2 <- c(0, -4.6, 3.4, "a")
my_log(num_vec2,4)