turbonss/FAQ.t2t

CMPH FAQ



- How do I define the ids of the keys?
	- You don't. The ids will be assigned by the algorithm creating the minimal
	  perfect hash function. If the algorithm creates an **ordered** minimal
	  perfect hash function, the ids will be the indices of the keys in the 
	  input. Otherwise, you have no guarantee of the distribution of the ids.

- Why do I always get the error "Unable to create minimum perfect hashing function"?
	- The algorithms do not guarantee that a minimal perfect hash function can
	  be created. In practice, it will always work if your input
	  is big enough (>100 keys). 
	  The error is probably because you have duplicated
	  keys in the input. You must guarantee that the keys are unique in the 
	  input. If you are using a UN*X based OS, try doing 
``` 	#sort input.txt | uniq > input_uniq.txt
	  and run cmph with input_uniq.txt

- Why do I change the hash function using  cmph_config_set_hashfuncs function and the default (jenkins) 
one is executed?
	- Probably you are you using the cmph_config_set_algo function after
	  the cmph_config_set_hashfuncs. Therefore, the default hash function 
	  is reset when you call the cmph_config_set_algo function. 


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