# vector not produced missing some '.' ?

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john birt on 7 Apr 2011
something is wrong with this code
t=0:0.1:1;
g = (0.30/(2*(pi*t^3)^0.5))*exp((-0.30^2)/(4*t));
As the vector g never gets made, I'm sure I need to put some '.' somewhere but I really don't understand this whole '.' stuff
Paulo Silva on 7 Apr 2011
Sean answer is great for such cases, also when there's one dot missing matlab tells you what's the operation in the error message:
mtimes % before *
mdivide % before /
mpower % before ^

Paulo Silva on 7 Apr 2011
t=0:0.1:1;
g = (0.30./(2*(pi*t.^3).^0.5)).*exp((-0.30^2)./(4*t));

Sean de Wolski on 7 Apr 2011
vectorize('g = (0.30/(2*(pi*t^3)^0.5))*exp((-0.30^2)/(4*t))');
A brainless way for us lazies.
Sean de Wolski on 7 Apr 2011
Eval, is the king of MATLAB laziness!

Matt Fig on 7 Apr 2011
As a general rule when dealing with operations on arrays, use a dot before every one of the three operators:
* / ^
If you do this you will be fine.
Sean de Wolski on 7 Apr 2011
and \

David Young on 7 Apr 2011
If you don't understand the operators, the most straighforward thing is to use
g = (0.30 ./ (2 .* (pi .* t .^ 3) .^ 0.5)) .* exp((-0.30 .^ 2) ./ (4 .* t));
so that all the operators behave as elementwise operators (which I guess is what you want). If you understand the difference, you can omit some of the dots, but they do no harm.
It's not all that hard really: *, / and ^ carry out matrix operations (like matrix multiplication, as defined here), while .*, ./ and .^ operate point by point on the elements of the matrices.