vector not produced missing some '.' ?

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]

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 ^

Answer 1

[Paulo Silva]

t=0:0.1:1;
g = (0.30./(2*(pi*t.^3).^0.5)).*exp((-0.30^2)./(4*t));

Answer 2

[Sean de Wolski]

vectorize('g = (0.30/(2*(pi*t^3)^0.5))*exp((-0.30^2)/(4*t))');

A brainless way for us lazies.

[Paulo Silva]

That's a good one, I must remember it :) +1 vote

but it too lazie, even for me lol

[Matt Fig]

Even better(?) and definitely lazier.

eval(vectorize('g = (0.30/(2*(pi*t^3)^0.5))*exp((-0.30^2)/(4*t))'))

[Paulo Silva]

... ..- .--. . .-. .-.. .- --.. .. .

[Sean de Wolski]

Eval, is the king of MATLAB laziness!

Answer 3

[Matt Fig]

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]

and \

Answer 4

[David Young]

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.