Sollya User's Manual

Name:

worstcase searches for hard-to-round cases of a function

Usage:

worstcase(function, preimage precision, preimage exponent range, image precision, error bound) : (function, integer, range, integer, constant) -> void worstcase(function, preimage precision, preimage exponent range, image precision, error bound, filename) : (function, integer, range, integer, constant, string) -> void

Parameters:

function represents the function to be considered
preimage precision represents the precision of the preimages
preimage exponent range represents the exponents in the preimage format
image precision represents the precision of the format the images are to be rounded to
error bound represents the upper bound for the search w.r.t. the relative rounding error
filename represents a character sequence containing a filename

Description:

The worstcase command is deprecated. It searches for hard-to-round cases of a function. The command searchgal has a comparable functionality.

Example 1:

   > worstcase(exp(x),24,[1,2],24,1b-26);
   prec = 165
   x = 1.99999988079071044921875 f(x) = 7.3890552520751953125 eps = 4.5998601423446695596184695493764120138001954979037e-9 = 2^(-27.695763)
   x = 2 f(x) = 7.38905620574951171875 eps = 1.44563608749673018122228379395533417878125150587072e-8 = 2^(-26.043720)