# Octave Basics

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For the meaning of operators, see the GNU Octave manual.

### The very basics

`+` , `-` , `*` , `/` , `^` , `pi` , `I` , `e` , `inf` , `eps` , `sin` , `cos` , `tan` , `exp` , `log` , `log10` , `abs` , `sqrt` , `sign` , `round` , `ceil` , `floor` , `fix` , `=` , `,` , `;` , `who` , `clear` , `help` , `lookfor`

```x = pi, y = floor (sin (x)), z = log (exp (2013)), z / inf
```

### Vectors and matrices

`:` , `.*` , `./` , `.^` , `'` , `.'` , `\` , `length` , `numel` , `size` , `zeros` , `ones` , `eye` , `diag` , `rand` , `det` , `trace` , `inv` , `lu` , `eig` , `cond` , `expm`

```x = 1:5, x(:), x(2:4), A = [11 12; 21, 22], A(1,1:end)
```

### Graphics

```t = 0:0.01*pi:21*pi; x = sin (t).*(exp (cos (t)) - 2*cos (4*t) + sin (t/12).^5); y = cos (t).*(exp (cos (t)) - 2*cos (4*t) + sin (t/12).^5); plot(x, y)
```

### Scripts and functions

`@` , `function` , `return` , `nargin` , `nargout` , `varargin` , `varargout` , `feval` , `eval`

```f = @(x) x.^2, f(1:10)

function v = cossum (x, n) v = cumsum (repmat (cos (x), 1, n));
```

### Programming elements

`==` , `>` , `<` , `>=` , `<=` , `!=` , `|` , `||` , `&` , `&&` , `!` , `~` , `if` , `else` , `elseif` , `for` , `while` , `end` , `break` , `continue` , `pause`

```for i = 1:5 if (i < 3) disp (i) else disp (i^2) endif endfor
```