I want to convert my triangular matrix into a vector. Let’s say I have 7×7 lower triangular matrix. Something like this: And I need to convert this matrix into a vector ignoring zeros. So, the result should be: I have already made a matrix by the following code: But I don’t really get how to …
Tag: matrix
Java – generate and rotate matrix
recently I’m trying to learn Java a bit and currently, I’m working on a simple program that should generate a matrix and then rotate it. I’m stuck at the first part. What exactly is the problem? The logic of my code seems to be fine, but anyway program is returning not what I would expect. T…
error: constructor in class cannot be applied to given types; with matrix of generic variable in Java
In a first file I declared the Matrix class with corresponding generic variable and with a constructor defined as follows: And in a second test file class with main program I declare the matrix of generic variables with String elements. Nevertheless I don´t quite understand why I get the error: If I´m using a…
Java multidimensional arrays – How to refer to the length of different dimensions
We are learning about 2D arrays in my AP computer science A class and I have a question that I’m struggling to find the clear answer to. For some context when I’m talking about my question, ragged arrays are out of the picture and when I refer to rows I am talking about arrays going across and whe…
Index of center of mxn matrix. if center does not exist, return the index of the square closest to the center with the highest integer
Trying to write a method which returns the center of the MxN matrix and if the center does not exist the method should return the index of the square closest to the center with the highest integer value Eg 1. – return [1,2] (Center does not exist so closest to the center is [[0, 7, 0],[6, 3, 4]] and 7
How to swap rows and columns of a 2d array? [duplicate]
This question already has answers here: Multi-dimensional array transposing (12 answers) Closed 1 year ago. I’m trying to write a method for ‘transpose’ a two-dimensional array of integers, in which the rows and columns of the original matrix are exchanged. However, I have no idea how I can …
Matrix multiplication in Java using 2D ArrayLists
I am trying to implement a simple matrix multiplication in Java, where I am storing the matrices in two-dimensional ArrayLists. It would seem the error is caused by the setting of matrix Result, inside the nested for loop, but I do not understand why. The code produces the result: when in fact it should be: A…
How to check if contours are the same?
I’ve got two images, the second one is the first one after modification. I find contours of two images and then check if there any same contours. The problem is, that despite contours being the same (drawing contours of one image and another one gives totally same results) after checking that it never b…
Creating a Matrix with ArrayLists
I want to create an ArrayList-matrix with n-rows and m-columns, for example I’ve already written a code for creating such a matrix but my code doesn’t display the values when I clear the list containing the column-data. Here is my Is there any possibility to clear the contents of intList without c…
Flip a Bitmap image horizontally or vertically
By using this code we can rotate an image: But how can we flip an image horizontally or vertically? Answer Given cx,cy is the centre of the image: Flip in x: Flip in y: Altogether: