Search results
Results from the WOW.Com Content Network
As exchanging the indices of an array is the essence of array transposition, an array stored as row-major but read as column-major (or vice versa) will appear transposed. As actually performing this rearrangement in memory is typically an expensive operation, some systems provide options to specify individual matrices as being stored transposed.
In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x) will result in an array y whose elements are sine of the corresponding elements of the array x. Vectorized index operations are also supported.
OFFT - recursive block in-place transpose of square matrices, in Fortran; Jason Stratos Papadopoulos, blocked in-place transpose of square matrices, in C, sci.math.num-analysis newsgroup (April 7, 1998). See "Source code" links in the references section above, for additional code to perform in-place transposes of both square and non-square ...
Indexes are also called subscripts. An index maps the array value to a stored object. There are three ways in which the elements of an array can be indexed: 0 (zero-based indexing) The first element of the array is indexed by subscript of 0. [8] 1 (one-based indexing) The first element of the array is indexed by subscript of 1. n (n-based indexing)
Index mapping (or direct addressing, or a trivial hash function) in computer science describes using an array, in which each position corresponds to a key in the universe of possible values. [1] The technique is most effective when the universe of keys is reasonably small, such that allocating an array with one position for every possible key ...
Thus, if we have a vector containing elements (2, 5, 7, 3, 8, 6, 4, 1), and we want to create an array slice from the 3rd to the 6th items, we get (7, 3, 8, 6). In programming languages that use a 0-based indexing scheme, the slice would be from index 2 to 5. Reducing the range of any index to a single value effectively eliminates that index.
As another example, many sorting algorithms rearrange arrays into sorted order in-place, including: bubble sort, comb sort, selection sort, insertion sort, heapsort, and Shell sort. These algorithms require only a few pointers, so their space complexity is O(log n). [1] Quicksort operates in-place on the data to be sorted.
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. C uses "Row Major" (SoA), which stores all the elements for a given row contiguously in memory. LAPACK defines various matrix representations in memory.