The interpreter is. But if you write vectorised code, we frequently are able to outperform Matlab.
Matlab used to have the same problem, and they even used to have docs on how to vectorise. When I first learned Matlab in 2004, they told me, "don't use loops". Twelve years later, you're supposed to write all the deeply-nested loops you want.
So yes, most Matlab code out there is loopy, so it's slow in Octave. But if you write it for Octave and don't make it loopy, it's quite good.
Matlab used to have the same problem, and they even used to have docs on how to vectorise. When I first learned Matlab in 2004, they told me, "don't use loops". Twelve years later, you're supposed to write all the deeply-nested loops you want.
So yes, most Matlab code out there is loopy, so it's slow in Octave. But if you write it for Octave and don't make it loopy, it's quite good.