Subject: integrate ( exp (x^3), x, 0, 1) still wrong
From: Edwin Woollett
Date: Fri, 11 May 2012 14:34:00 -0700
This is an integral which gave a history stack
overflow lisp error in 5.26.0 (Jan 17, 2012).
Using the lastest gcl 5.27.0-1, there is no longer
a stack problem, but a wildly wrong answer.
(%i1) (display2d:false,fpprintprec:8)$
(%i2) integrate(exp(x^3),x,0,1);
(%o2) (gamma_incomplete(1/3,-1)-gamma(1/3))/3
(%i3) float(%);
(%o3) 0.333333*(-3.4863699*%i-2.0128566)
(%i4) expand(%);
(%o4) -1.1621233*%i-0.670952
(%i5) quad_qags(exp(x^3),x,0,1);
(%o5) [1.3419044,1.48981318E-14,21,0]
(%i6) build_info();
(%o6) ?%build_info("5.27.0","2012-05-08 11:27:57","i686-pc-mingw32",
"GNU Common Lisp (GCL)","GCL 2.6.8")
Ted Woollett