Test whether this is the zero matrix

Note that this function tests whether the elements of abs(a) are <= tol. The default value for tol is 1e-6. So, you can set tol = 0 to discover if a is EXACTLY the zero matrix.

Usage

iszero_byname(a, tol = 1e-06)

Arguments

a

A matrix or list of matrices.

tol

The allowable deviation from 0 for any element. Interpreted as an absolute value.

Value

TRUE Iff this is the zero matrix within tol.

Examples

zero <- matrix(0, nrow = 50, ncol = 50)
iszero_byname(zero)
#> [1] TRUE
nonzero <- matrix(1:4, nrow = 2)
iszero_byname(nonzero)
#> [1] FALSE
# Also works for lists
iszero_byname(list(zero, nonzero))
#> [[1]]
#> [1] TRUE
#> 
#> [[2]]
#> [1] FALSE
#> 
# And it works for data frames
DF <- data.frame(A = I(list()), B = I(list()))
DF[[1,"A"]] <- zero
DF[[2,"A"]] <- nonzero
DF[[1,"B"]] <- nonzero
DF[[2,"B"]] <- zero
iszero_byname(DF$A)
#> [[1]]
#> [1] TRUE
#> 
#> [[2]]
#> [1] FALSE
#> 
iszero_byname(DF$B)
#> [[1]]
#> [1] FALSE
#> 
#> [[2]]
#> [1] TRUE
#> 
iszero_byname(matrix(1e-10, nrow = 2))
#> [1] TRUE
iszero_byname(matrix(1e-10, nrow = 2), tol = 1e-11)
#> [1] FALSE