Added gperf notes.
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davi
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BMZ.t2t
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BMZ.t2t
@ -21,6 +21,3 @@ Enjoy!
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Davi de Castro Reis
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Fabiano Cupertino Botelho
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%!include(html): ''LOGO.html''
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Last Updated: %%date(%c)
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Before Width: | Height: | Size: 360 B After Width: | Height: | Size: 303 B |
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CHM.t2t
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CHM.t2t
@ -19,6 +19,3 @@ Enjoy!
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Davi de Castro Reis
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Fabiano Cupertino Botelho
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%!include(html): ''LOGO.html''
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Last Updated: %%date(%c)
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@ -22,6 +22,3 @@ Enjoy!
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Davi de Castro Reis
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Fabiano Cupertino Botelho
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%!include(html): ''LOGO.html''
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Last Updated: %%date(%c)
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40
GPERF.t2t
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GPERF.t2t
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@ -0,0 +1,40 @@
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GPERF versus CMPH
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You might ask why cmph if [gperf http://www.gnu.org/software/gperf/gperf.html]
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already works perfectly. Actually, gperf and cmph have different goals.
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Basically, these are the requirements for each of them:
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- GPERF
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- Create very fast hash functions for **small** sets
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- Create **perfect** hash functions
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- CMPH
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- Create very fast hash function for **very large** sets
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- Create **minimal perfect** hash functions
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As result, cmph can be used to create hash functions where gperf would run
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forever without finding a perfect hash function, because of the running
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time of the algorithm and the large memory usage.
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On the other side, functions created by cmph are about 2x slower than those
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created by gperf.
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So, if you have large sets, or memory usage is a key restriction for you, stick
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to cmph. If you have small sets, and do not care about memory usage, go with
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gperf. The first problem is common in the information retrieval field (e.g.
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assigning ids to millions of documents), while the former is usually found in
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the compiler programming area (detect reserved keywords).
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----------------------------------------
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[Home index.html]
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----------------------------------------
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Davi de Castro Reis
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Fabiano Cupertino Botelho
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@ -3,7 +3,7 @@ CMPH - C Minimal Perfect Hashing Library
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%!includeconf: CONFIG.t2t
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----------------------------------------
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-------------------------------------------------------------------
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**Description**
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@ -14,8 +14,8 @@ production-quality and fast API. The library is designed to work with big entrie
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can not fit in the main memory. It has been used successfully for constructing minimal perfect
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hashing functions for sets with more than 100 million of keys.
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Although there is a lack of similar libraries
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in the free software world, we can point out some of the distinguishable
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features of cmph:
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in the free software world ([gperf is a bit different gperf.html]), we can point out some
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of the distinguishable features of cmph:
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- Fast.
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- Space-efficient with main memory usage carefully documented.
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@ -28,7 +28,6 @@ features of cmph:
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- Well encapsulated API aiming binary compatibility through releases.
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- Free Software.
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----------------------------------------
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**Supported Algorithms**
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