# isequaln

Test symbolic objects for equality, treating `NaN` values as equal

## Syntax

``isequaln(A,B)``
``isequaln(A1,A2,...,An)``

## Description

example

````isequaln(A,B)` returns logical `1` (true) if `A` and `B` are the same size and their contents are of equal value. Otherwise, `isequaln` returns logical `0` (false). All `NaN` (not a number) values are considered to be equal to each other. `isequaln` recursively compares the contents of symbolic data structures and the properties of objects. If all contents in the respective locations are equal, `isequaln` returns logical `1` (true).```

example

````isequaln(A1,A2,...,An)` returns logical `1` (true) if all the inputs are equal.```

## Examples

### Compare Two Expressions

Use `isequaln` to compare these two expressions:

```syms x isequaln(abs(x), x)```
```ans = logical 0```

For positive `x`, these expressions are identical:

```assume(x > 0) isequaln(abs(x), x)```
```ans = logical 1```

For further computations, remove the assumption on `x` by recreating it using `syms`:

`syms x`

### Compare Two Matrices

Use `isequaln` to compare these two matrices:

```A = hilb(3); B = sym(A); isequaln(A, B)```
```ans = logical 0```

### Compare Vectors Containing `NaN` Values

Use `isequaln` to compare these vectors:

```syms x A1 = [x NaN NaN]; A2 = [x NaN NaN]; A3 = [x NaN NaN]; isequaln(A1, A2, A3)```
```ans = logical 1```

## Input Arguments

collapse all

Inputs to compare, specified as symbolic numbers, scalar variables, matrix variables (since R2021a), expressions, functions, vectors, or matrices. If one of the arguments is a symbolic object and the other one is numeric, the toolbox converts the numeric object to symbolic before comparing them.

Series of inputs to compare, specified as symbolic numbers, scalar variables, matrix variables (since R2021a), expressions, functions, vectors, or matrices. If at least one of the arguments is a symbolic object, the toolbox converts all other arguments to symbolic objects before comparing them.

## Tips

• Calling `isequaln` for arguments that are not symbolic objects invokes the MATLAB® `isequaln` function. If one of the arguments is symbolic, then all other arguments are converted to symbolic objects before comparison.

• `isequaln(A,B)` checks if `A` and `B` are the same size and their contents are syntactically the same expression, treating `NaN` values as equal. To check whether the mathematical comparison `A == B` holds for all values of variables in `A` and `B`, use ```isAlways(A == B)```.

## Version History

Introduced in R2013a