Useful Matlab's functions


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Functions ==> Actions



uread ==> read

x = uread('Calvi.X')

Type ==> affiche contenu

Type fonction

Which ==> where is a command ?

which commande

Edit ==> launching text editor


'; '==> don't screening results


Whos ==> Check of all variables in workspace


Clear ==> Clean a variable

clear ans

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

diary filename


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

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


.* ==> Elements multipliate between us


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

% ==> comments

Load ==>Load a file

load filename.txt

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

save test_new.mat


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


  • 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


figure ==> Creer une autre fenetre de plot

plot (x,y1,'r--')
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


  • bar ==> do histogram

  • pcolor ==> do an area graph

don't forget to transpose matrix ...

pcolor(A'), shading flat, colorbar

for more informations go to


Path ==> search functions


Set path ==> see or modify a function

Set Path

Some about Octave

Wikibook about Octave :

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

As Linux command

Dir = ls

Type = cat

Delete = rm

Cd = cd

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