import mpmath
mpmath.mp.pretty=True
mpmath.mp.dps=30
def F(x):
        return mpmath.zeta(x)+mpmath.zeta(x,derivative=1)

r=mpmath.findroot(F,[0.1+mpmath.j],solver="muller")

====
Unhandled SIGSEGV: A segmentation fault occurred in Sage.
This probably occurred because a *compiled* component of Sage has a bug
in it and is not properly wrapped with sig_on(), sig_off(). You might
want to run Sage under gdb with 'sage -gdb' to debug this.
Sage will now terminate.
=====

Hmm.  My backtrace showed:

/home/mcneil/sagedev/sage-5.4.beta0/local/lib/libcsage.so(print_backtrace+0x3b)[0xb6bd7c49]
/home/mcneil/sagedev/sage-5.4.beta0/local/lib/libcsage.so(sigdie+0x17)[0xb6bd7c89]
/home/mcneil/sagedev/sage-5.4.beta0/local/lib/libcsage.so(sage_signal_handler+0x212)[0xb6bd778c]
[0xb772c400]
/home/mcneil/sagedev/sage-5.4.beta0/local/lib/libgmp.so.7(__gmpn_rshift+0x19c)[0xb6b897dc]

and my standard Python version of mpmath, which I don't think is
gmp-aware, produces

/usr/local/lib/python2.7/dist-packages/mpmath/libmp/libelefun.pyc in
exp_fixed(x, prec, ln2)
   1410         return v << n
   1411     else:
-> 1412         return v >> (-n)
   1413
   1414

OverflowError: long int too large to convert to int


Doug

i get the same exception on standalone mpmath, don't know if it uses
gmp.