command in Matlab equivalent to "forall " in fortran

Hi Is there any command in matlab that can simpilfy such loop:

for i=1:10 A(i)=i^2 end

as I know in fortran it can be written anr run very fast as FORALL(i=1,10) A(i)=i**2

I hope similar thing can be found in Matlab too.

Answer 1

[Daniel Shub]

The JIT accelerator that was introduced 10 years ago has sped up loops substantially, it is an unfortunate myth that MATLAB loops are slow. Vectorization can speed up some loops, but it can also slow things down. The ability to use parfor loops can also speed up things (and allow scaling) that is not easy with vectorized code.

For you case of wanting a user-defined function to be vectorized, the easy answer is to go back to the function (jmat_TM) and modify it to handle vector inputs.

[smabtahi]

Thanks Daniel and Jan

Then it seems that I have no other choise than vectorizing jmat_TM.

[Daniel Shub]

Or you could just stick with your loop. There is no guarantee that vectorizing will speed things up, although it will make your code for jmat_TM much more MATLAB like.

Answer 2

[Wayne King]

 A = 1:10;
 A = A.^2;

[smabtahi]

Thank you Wayne.

of course the power function in pre-defined in matlab for whole matrixes, but consider a user defined function, for instance this loops:

for id=1:10

for jmd=1:100;

[Jsen(id,jmd)]=jmat_TM(id,jmd);

end

end

and jmat_TM is a user-defined complicated function. I want to get rid of using those loops.

[Jan]

You can omit the square brackest around the output here.

You need either the loops or rewrite the user defined function, that it accepts matrices as inputs. Therefore Wayne's suggestion is fine.