¿Por qué la fila principal es más rápida que la columna principal?

Why row-Major is faster than column major?

Reading memory in contiguous locations is faster than jumping around among locations. As a result, if the matrix is stored in row-major order, then iterating through its elements sequentially in row-major order may be faster than iterating through its elements in column-major order.

The elements of a 2D array are arranged in rows and columns, and the new operator for 2D arrays specifies both the number of rows and the number of columns. For example, int[][] A; A = new int[3][4]; This creates a 2D array of int that has 12 elements arranged in 3 rows and 4 columns.

Column-major order for 2D arrays refers to a traversal path which moves vertically down each column starting at the first column and ending with the last. In order to perform column-major traversal, we need to set up our nested loops in a different way.

The difference between the orders lies in which elements of an array are contiguous in memory. In row-major order, the consecutive elements of a row reside next to each other, whereas the same holds true for consecutive elements of a column in column-major order.

Programming languages and environments typically assume a single array layout for all data. MATLAB® and Fortran use column-major layout by default, whereas C and C++ use row-major layout.

The Python NumPy library is very general. It can use either row-major or column-major ordered arrays, but it defaults to row-major ordering.

Matrix Definition The number of rows and columns that a matrix has is called its dimension or its order. By convention, rows are listed first; and columns, second.

This is not, however, the case with a 2D array, rows come first and then columns. Consider the following analogy: in geometry one walks to the ladder (X axis) and climbs it (Y axis). Conversely, in Java one descends the ladder (rows) and walks away (columns).

Each element of the outer array has a reference to each inner array. The picture below shows a 2D array that has 3 rows and 7 columns. Notice that the array indices start at 0 and end at the length – 1. The outer array can be thought of as the rows and the inner arrays the columns.

Matrix Definition A matrix is a rectangular array of numbers arranged in rows and columns. The array of numbers below is an example of a matrix. The number of rows and columns that a matrix has is called its dimension or its order. By convention, rows are listed first; and columns, second.