In is answer to the squestion How to properly time Sage computations? Dan Fulea propose a cheap approach which looks like this (adapted to my problem
n=10000
m=1000
AA = random_matrix(RR,n,m)
BB = transpose(AA)
AA2= np.array(AA)
BB2=np.array(BB)
##### Commande pour mesurer le temps pris par l'opération
import time #
t1=time.time()#
CC2=AA2.dot(BB2)
t2=time.time()#
temps_op = t2-t1#
show(temps_op)
But what is the measure. How to transform temps_op in second, minutes... ?
