Array that replaces runtime computation with a simpler array indexing operation
In computer science, a lookup table (LUT) is an array that replaces runtime computation with a simpler array indexing operation, in a process termed as direct addressing. The savings in processing time can be significant, because retrieving a value from memory is often faster than carrying out an "expensive" computation or input/output operation.[1] The tables may be precalculated and stored in static program storage, calculated (or "pre-fetched") as part of a program's initialization phase (memoization), or even stored in hardware in application-specific platforms. Lookup tables are also used extensively to validate input values by matching against a list of valid (or invalid) items in an array and, in some programming languages, may include pointer functions (or offsets to labels) to process the matching input. FPGAs also make extensive use of reconfigurable, hardware-implemented, lookup tables to provide programmable hardware functionality.
LUTs differ from hash tables in a way that, to retrieve a value with key , a hash table would store the value in the slot where is a hash function i.e. is used to compute the slot, while in the case of LUT, the value is stored in slot , thus directly addressable.[2]: 466
^McNamee, Paul (21 August 1998). "Automated Memoization in C++". Archived from the original on 16 April 2019.{{cite web}}: CS1 maint: unfit URL (link)
^Kwok, W.; Haghighi, K.; Kang, E. (1995). "An efficient data structure for the advancing-front triangular mesh generation technique". Communications in Numerical Methods in Engineering. 11 (5). Wiley & Sons: 465–473. doi:10.1002/cnm.1640110511.
In computer science, a lookuptable (LUT) is an array that replaces runtime computation with a simpler array indexing operation, in a process termed as...
In the film and graphics industries, 3D lookuptables (3D LUTs) are used for color grading and for mapping one color space to another. They are commonly...
Table-lookup synthesis (or Wavetable-lookup synthesis) (Roads 1996) is a class of sound synthesis methods using the waveform tables by table-lookup,...
well-dimensioned hash table, the average time complexity for each lookup is independent of the number of elements stored in the table. Many hash table designs also...
The bagua (Chinese: 八卦; pinyin: bāguà; lit. 'eight trigrams') is a set of symbols from China intended to illustrate the nature of reality as being composed...
A CUSIP (/ˈkjuːsɪp/) is a nine-character numeric or alphanumeric code (e.g. 037833100 for Apple) that uniquely identifies a North American financial security...
halftone image. The lookuptable provides a continuous-tone value for a given pixel and its distribution. The corresponding lookuptable is obtained before...
previous one. This, the second lookup cannot begin until the first lookup is complete. When sliced tables are used, both lookups can begin at the same time...
A shift register lookuptable, also shift register LUT or SRL, refers to a component in digital circuitry. It is essentially a shift register of variable...
hardware, generate a fake page table, changing registers to point towards the new page table, and invoking the LookupTable to perform a uPPL call. As the...
against their corresponding denoted sequence, using a lookuptable. In the original paper, this lookuptable is encoded and stored alongside the compressed text...
directly, by hand or using a calculator, or indirectly using a lookuptable (or chart). The table displays BMI as a function of mass and height and may show...
implement a lookuptable with constant worst-case access time. A perfect hash function can, as any hash function, be used to implement hash tables, with the...
a professor of mathematics at Lynchburg College. Missing values in a lookuptable used by the FPU's floating-point division algorithm led to calculations...
used to "drive" the logic of the program. A simple example might be a lookuptable containing a range of possible input values and a function pointer to...
return 1 [by the convention that 0! = 1] else if n is in lookup-table then return lookup-table-value-for-n else let x = factorial(n – 1) times n [recursively...
memory access will continue. The page tablelookup may fail, triggering a page fault, for two reasons: The lookup may fail if there is no translation available...
so that the same program could operate a web-based WHOIS lookup, and an external TLD table to support multiple WHOIS servers based on the TLD of the...
perpetual calendars require no calculation by the user, and are essentially lookuptables. A typical application is to calculate the day of the week on which...
maintain multiple tables, and each lookup must search through each table. Rainbow tables can achieve similar performance with tables that are k times larger...
Sarcalumenin, human protein that regulates calcium transport Shift register lookuptable, a component in digital circuitry Student Rugby League, UK Semiconductor...
stored. Thus, this table takes a total of (n/s)lgl=4nlglgn/lgn{\displaystyle (n/s)\lg l=4n\lg \lg n/\lg n} bits. A lookuptable Rp{\displaystyle R_{p}}...
Global Information
