I have the following code, and it is not working, because c2 is a 1*1 adjoint float type array. If I define b2=ones(3), then the code will work. The question is that how to manually change the type of c2 ?(In my application, b2 is extracted from a matrix and couldn’t be defined). using LinearAlgebr…

Can you explain a bit more of what you’re trying to achieve? c2 is a 1x1, so taking its determinant doesn’t seem very useful.

[image] FiniteelementDuan: c2=a’*b2 At least you can write: c2 = a' * vec(b2)

It is from a Jacobian matrix, and the dimension of the matrix could be 1x1, 2x2, or 3x3. I would like to keep the same form for all dimensions. The output I need is a number, rather than a 1x1 array. One the other hand, a zeros(3) vector is different to a zeros(3,1) vector in terms of array type. …

Thanks. It looks like a strange issue.

If that’s the case then I assume a will also be a matrix. The following works if a is a matrix. julia> a = rand(3,2); b = rand(3, 2); julia> a' * b 2×2 Array{Float64,2}: 0.767651 0.615483 0.478253 0.40591 julia> det(a' * b) 0.017240560608832924

Yes. It is only not working for one dimensional problems!

It seems that Julia is making zeros(3,1) as a two dimensional array, rather than a one dimensional vector. This seems to be a mistake for me.

[image] FiniteelementDuan: It seems that Julia is making zeros(3,1) as a two dimensional array, rather than a one dimensional vector. This seems to be a mistake for me. This is intentional. Use zeros(3) for a vector (and you also get a vector when slicing a column from a matrix).

Array type modification

New to Julia

kristoffer.carlsson August 15, 2018, 12:45pm 2

Please read PSA: how to quote code with backticks

Topic		Replies	Views
Julia type displaying change between versions New to Julia	49	2529	August 10, 2022
Matrix multiplication - inconsistent behaviour General Usage question	50	3177	May 16, 2020
Vector{Vector} indices General Usage indexing , arrays	22	3176	September 19, 2022
Error in mul!(c,a,b) if size(b) = (n,1) General Usage	28	1683	October 10, 2020
Same expression returning inconsistent data types brings considerable inconvenience General Usage question	29	930	April 30, 2024

Array type modification

Related topics