# Mex Problem

Asked by Chris on 19 Jun 2012
Latest activity Answered by Jan Simon on 20 Jun 2012

Good Day,

I'm trying to test a mex function I wrote but keep getting the following:

```Error: File: test.m Line: 3 Column: 31
Unexpected MATLAB expression.
```

What I want to do is pass the following arrays to my mex function that will double them:

```TurbineComponentsBlade = ((1 1 1) (1 1 1; 1 1 1) (1 1 1) (1 1 1)) ;
```
```TurbineComponentsBladeLength = 1;
```
```TurbineComponentsHub = ((1 1 1) (1 1 1; 1 1 1) (1 1 1) (1 1 1)) ;
```
```TurbineComponentsRotorFurl = ((1 1 1) (1 1 1; 1 1 1) (1 1 1) (1 1 1)) ;
```
```TurbineComponentsNacelle = ((1 1 1) (1 1 1 ;1 1 1) (1 1 1) (1 1 1)) ;
```
```TurbineComponentsTailfin = ((1 1 1) (1 1 1; 1 1 1) (1 1 1) (1 1 1)) ;
```
```TurbineComponentsTower = ((1 1 1) (1 1 1; 1 1 1) (1 1 1) (1 1 1)) ;
```
```TurbineComponentsSubstructure = ((1 1 1) (1 1 1; 1 1 1) (1 1 1) (1 1 1)) ;
```

The error I keep receiving is that the "1" in the first 3x1 matrix, 2nd location is unexpected. Also the "1" in the 3x3 matrix (5th location from left to right) is unexpected. I imagine my matlab coding is wrong since I'm still learning it but if anyone could help me it would be appreciated.

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Answer by Walter Roberson on 19 Jun 2012

3 x 1 matrix: [1; 1; 1]

3 x 3 matrix: [1 1 1; 1 1 1; 1 1 1]

Short forms for these are: ones(3,1) and ones(3,3)

You cannot combine a 3 x 1 matrix and a 3 x 3 matrix in a single variable unless you use cell arrays:

`   {ones(3,1) ones(3,3)}`