# iszero_byname: Test whether this is the zero matrix In matsbyname: An Implementation of Matrix Mathematics

 iszero_byname R Documentation

## Test whether this is the zero matrix

### Description

Note that this function tests whether the elements of `abs(a)` are `<= tol`. 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 of list of matrices `tol` the allowable deviation from 0 for any element

### Value

`TRUE` iff this is the zero matrix within `tol`.

### Examples

```zero <- matrix(0, nrow = 50, ncol = 50)
iszero_byname(zero)
nonzero <- matrix(1:4, nrow = 2)
iszero_byname(nonzero)
# Also works for lists
iszero_byname(list(zero, nonzero))
# 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)
iszero_byname(DF\$B)
iszero_byname(matrix(1e-10, nrow = 2))
iszero_byname(matrix(1e-10, nrow = 2), tol = 1e-11)
```

matsbyname documentation built on April 2, 2022, 1:06 a.m.