Search results
Results from the WOW.Com Content Network
In computing, row-major order and column-major order are methods for storing multidimensional arrays in linear storage such as random access memory. 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 ...
Illustration of row- and column-major order. Matrix representation is a method used by a computer language to store column-vector matrices of more than one dimension in memory. Fortran and C use different schemes for their native arrays. Fortran uses "Column Major" , in which all the elements for a given column are stored contiguously in memory.
A programmer (or a sophisticated compiler) may use this information to choose between row- or column-major layout for each array. For example, when computing the product A · B of two matrices, it would be best to have A stored in row-major order, and B in column-major order.
Illustration of row- and column-major order. The major purpose of loop interchange is to take advantage of the CPU cache when accessing array elements. When a processor accesses an array element for the first time, it will retrieve an entire block of data from memory to cache.
For example, with a matrix stored in row-major order, the rows of the matrix are contiguous in memory and the columns are discontiguous. If repeated operations need to be performed on the columns, for example in a fast Fourier transform algorithm (e.g. Frigo & Johnson, 2005), transposing the matrix in memory (to make the columns contiguous) may ...
The three important reasons for knowing whether a particular computer language compiler are row-major or column major: 1. most common is that the graphics adapter memory order has to be matched to main memory array order, or, at the least, performance suffers because the the data has to move just one cell (oe even pixel) at time if mismatched, otherwise large block moves can work.
This page was last edited on 19 November 2016, at 10:46 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.
Row- and column-major order; S. Sorted array; Sparse matrix; Stride of an array; Suffix array; V. Variable-length array This page was last edited on 24 May 2016, at ...