Jeroen Demeyer on Sat, 09 Nov 2013 16:19:46 +0100

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Large errors for eint()

It seems that the eint() function can have quite large errors in its approximation.

Just one example with a relative error of over 28 bits:
gp> \p 481
   realprecision = 481 significant digits
gp> x = eint1(15);
gp> \p 500
   realprecision = 500 significant digits
gp> y = eint1(15);
gp> (x-y)/x * 2^1600
%19 = 418655076.1440077999

With the vector version of eint1, errors can be even larger.

Do you consider this a bug?