Here is how you can do it: m 5 columns of submatrix n 4 rows of submatrix k 50 num submatrixes in matrix column l 50 num submatrixes in matrix row A rand (mk,nl. So for your problem, some additional steps are necessary. Thanks for clearing up my confusion, really learning a lot here. Matlabs reshape function is pretty handy (and fast), but always reads and writes complete columns. Learn more about matlab programming MATLAB Hi, I have to convert a matrix in one column/row vector composed of all the rows of the original matrix. I might be a bit “stuck in my ways”, I just like having the arrays exactly as they should be mathematically. Convert matrix in single column/row vector. So depending on whether or not my array is a matrix or a vector my transferdata function uses the correct method to change the values of the preallocated array when reading data from binary files. You are right it makes generic code a bit harder to do, currently I overcome these problems using multiple dispatch like this: function _transferDataBi4(ft::IOStream, arrayVal::AbstractMatrix)įunction _transferDataBi4(ft::IOStream, arrayVal::AbstractVector) Position and velocity is described with cartesian coordinates, so basically they would need to be described with a Nx3 matrix, while density is would only need a vector or a matrix of Nx1. These particles can have properties like position, velocity, density and so on. Thanks for making me aware of I am working with post-processing of particle simulations, so let us say I have N particles. And you are absolutely right, I could just do: zeros(Float64,5)Īnd then get what I wanted. That is right, I’ve been used to call everything arrays, but will try to remember the distinction in the future. Even single, scalar, numbers are 1x1 matrices, unlike in Julia, where Matrix, Vector and Number are different types. Matlab does not have the concept of vectors, everything is a matrix, so you can only get 4x1 matrices when you want a length 4 vector. Perhaps using a 4x1 matrix is more appropriate in your case.Įdit: Perhaps your confusion stems from Matlab. You should however consider whether this is the right thing to do. Converting a 4x1 matrix to a vector is most easily done with vec(x) If, on the other hand, x is always a matrix, but sometimes has just one column, then you have use some sort of if condition. Where does nCol come from? If you have an input array x (either vector or matrix) then you can write: zeros(size(x)) Now, you have discovered one way of accomplishing what you wanted, but it would be easier if we knew what your inputs are. It’s easier if you use the words ‘matrix’ and ‘vector’ instead of calling everything ‘arrays’.įirstly, note that you can construct a zero-valued vector like this: zeros(4) In this tutorial you will learnhow to reshape a matrix in matlab,guide to reshape a matrix in matlab,how to change the shape of matrix in matlab,how to use r. If you want a flat vector, that is not a 4x1 array, but rather a ‘length 4 vector’. Thanks again berak.It is confusing that you are using the term ‘4x1 array’ when talking about a vector. Is there another function to reshape a 2D Mat ?ĮDIT: Okay it seems like my understanding of the reshape function was totally wrong. Using the elements from A, create a 2-by-2-by-3 multidimensional array. As long as the number of elements in each shape are the same, you can reshape them into an array with any number of dimensions. For example, reshape a 3-by-4 matrix to a 2-by-6 matrix. Im(0,1) should be equal to temp(113,0) or temp(93,0) but I am not getting such values. The reshape function changes the size and shape of an array. What I am getting above is that the elements in (0,0) and (0,1) are equal to (0,0) and (1,0) after being reshaped. Here is the short piece of code that I have cout (0,0) (0,1) (0,0) (1,0) << endl The transpose puts the elements in memory in the order 1,2,3,4 so that the reshape works as you want. 39 becomes the SECOND element and i dunno where the -44 goes to. ,1,4) MATLAB array memory is column-wise, so in memory the 'a' elements are stored 1,3,2,4. Here is the small code snippet and the expected result. I tried using reshape but I was not successful. If i am wrong then please tell me how do i convert a 2D matrix into a 1D column vector.ĮDIT: I dunno how to show the code. I have a MxN Matrix and would like to convert into a vector MNx1 with all the elements of the row from the Matrix as the elements of the Vector. I use reshape(0,9) so the M.at(0,1) should be the 4th element but it becomes the 2nd element.
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