7

2

I have a lot of $\LaTeX$ matrices, and I want to find their eigenvalues and eigenvectors.

I tried to import them to Mathematica with:

```
ToExpression["[MATRIX PASTED FROM LATEX]",TeXForm]
```

This method worked for everything I tried until now, as long as it wasn't a matrix. For some reason, Mathematica thinks of the matrix as some kind of "ExpressionCell" That I know nothing of.

Here is an example of this problem:

Input:

```
ToExpression["\\begin{matrix}{0} & {0} & {0}\\\\
{\\sqrt{2}} & {0} & {0}\\\\
{0} & {\\sqrt{2}} & {0}
\\end{matrix}", TeXForm]
```

Output: (I converted it to InputForm so you can see the problem)

```
ExpressionCell[TraditionalForm[{{TextCell[Row[{ , TextCell[0, InlineFormula], }]],
TextCell[Row[{ , TextCell[0, InlineFormula], }]],
TextCell[Row[{ , TextCell[0, InlineFormula], }]]},
{TextCell[Row[{ , ExpressionCell[2, InlineFormula], }]],
TextCell[Row[{ , TextCell[0, InlineFormula], }]],
TextCell[Row[{ , TextCell[0, InlineFormula], }]]},
{TextCell[Row[{ , TextCell[0, InlineFormula], }]],
TextCell[Row[{ , ExpressionCell[2, InlineFormula], }]],
TextCell[Row[{ , TextCell[0, InlineFormula], }]]}}]]
```

When I ran the code the matrix **looks** fine - like a Matrix. But Mathematica just doesn't think of it as a matrix, and therefor can't find it's eigenvalues (or do any kind of calculations).

I'm stuck here. Does anyone how to input matrices into Mathemtica?

Any help would be appreciated!

P.S. I found that I'm not the only one stuck with this problem:

My WinEdt fails with compiling your \ begin{matrix}{0} & {0} & {0}\ \ {\ sqrt{2}} & {0} & {0}\ \ {0} & {\ sqrt{2}} & {0} \ end{matrix}. Is it OK? – user64494 – 2019-06-29T19:41:40.633