# Useful Matlab's functions

Functions ==> Actions
```Syntaxe
```

## General

```x = uread('Calvi.X')
```

Type ==> affiche contenu

```Type fonction
```

Which ==> where is a command ?

```which commande
```

Edit ==> launching text editor

```edit
```

'; '==> don't screening results

```commandX;
```

Whos ==> Check of all variables in workspace

```whos
```

Clear ==> Clean a variable

```clear ans
```

Diary ==> Create a diary of your Matlab in disk file

```diary filename
```

## Matrix

A(3,2) ==> A matrice See the 2nd element of the 3rd row

```A(3,2)
A(3,2) = 30
```

A(3,2) = 30 ==> Replace the 2nd element of the 3rd row by 30

```A(3,1:4) = [1 3 3 5]
```

Replace the 3rd row by [...,..,..]

a:b ==> go a to b

```c = o : 10
c =o 1 2 3 4 5 6 7 8 9 10
c = 1 : 0.5 : 10
Go 1 to 10 with an increment of 0.5
C = 1 : 0.5 : 10
```

' ==> tranposed

```M'
```

.* ==> Elements multipliate between us

```A.*B
```

example : A.^2 squares each element of the matrix

```load filename.txt
```

Save ....mat ==>Save and include in workspace (fichier binaire)

```save test_new.mat
Nomscript.m
```

## Help

Help ==> informations about command or scripts

```help scriptname
```

helpwin elfun ==> listing of elementary functions

helpwin specfun ==> listing of specialised functions

helpwin elmat ==> matrix functions

helpwin punct ==> specialised characters

## Graphics

• Plot ==> a line graphic

Plot ==> plotting when 2 vectors have the same lenght (y=f(y))

```plot (x,y)
```

Plot 'r-' 'r--' ==> Plot y1 en rouge pointillé ('r--') et y2 en bleu continu ('b-') plot (x, y1, 'r--', x,y2, 'b-')

Plot just a point

```plot(....,'k*'...)
```

figure ==> Creer une autre fenetre de plot

```plot (x,y1,'r--')
figure
plot (x,y2,'b--')
```

clf ==> clear figures

hold ==> add plots on the same figure

```plot (x,y1,'r--')
hold on            %ouvre
bar (x,y2)
hold off           %ferme
```

Subplot ==> plotting many figures in parallel in a same window

```subplot (m, n, p) :
m : nombre de division en ligne
n : nombre de division verticale
p : régio active pour le graphe
```

subplot (2,1,1), plot (x, y1, 'r--')

subplot (2,1,2), plot (x, y2)

Axis ==>Scaling of the axis >> plot (x,y1,'r--') >> axis ([xmin xmax ymin ymax]) Axis square

Axes carrés >> axis square

Title ==> put a title

```title('c est bidon')
```

Xlabel ylabel ==> name axis

```xlabel ('x-axis')
ylabel ('bibi')
```

grid ==> put a grid

```grid
```

• bar ==> do histogram

• pcolor ==> do an area graph

don't forget to transpose matrix ...

```pcolor(A'), shading flat, colorbar
```

## Functions

Path ==> search functions

```path
```

Set path ==> see or modify a function

```Set Path
```

help -i : for help

look for keywords : find function according keywords

pkg load yapso : launch Yapso

pkg unload yapso : to close yapso close

pcolor (variable) : plot 'variable'

variable' : transpose variable

colorbar : display the color bar

ncdump -h filename.ext : donne ce qu'il y a dans le fichier

Dir = ls

Type = cat

Delete = rm

Cd = cd