Here is some debug info.
(if i change 44 to 43 don't crash).
Searching for the top of stack returns this:
http://projects.scipy.org/scipy/ticket/1611
interp1d gives a Segmentation fault when 1. using kind='cubic' and if the original data-set is greater than 119
g=graphs.CycleGraph(44);m=g.adjacency_matrix();m^7
Program received signal SIGSEGV, Segmentation fault.
0x00007fffec15dd4d in ATL_dupMBmm0_8_0_b0 ()
from /opt/sage/sage-5.3-linux-64bit-ubuntu_10.04.4_lts-x86_64-Linux/local/lib/libatlas.so
(gdb) x/i $pc
=> 0x7fffec15dd4d <ATL_dupMBmm0_8_0_b0+13>: ldmxcsr -0x4(%rsp)
(gdb) p/x $rsp
$1 = 0x7fffffffb848
(gdb) bt
#0 0x00007fffec15dd4d in ATL_dupMBmm0_8_0_b0 ()
from /opt/sage/sage-5.3-linux-64bit-ubuntu_10.04.4_lts-x86_64-Linux/local/lib/libatlas.so
#1 0x00007fffec1a8dac in ATL_dIBNBmm ()
from /opt/sage/sage-5.3-linux-64bit-ubuntu_10.04.4_lts-x86_64-Linux/local/lib/libatlas.so
#2 0x00007fffec1b2035 in ATL_dmmJIK2 ()
from /opt/sage/sage-5.3-linux-64bit-ubuntu_10.04.4_lts-x86_64-Linux/local/lib/libatlas.so
#3 0x00007fffec1b28ea in ATL_dmmJIK ()
from /opt/sage/sage-5.3-linux-64bit-ubuntu_10.04.4_lts-x86_64-Linux/local/lib/libatlas.so
#4 0x00007fffec1aa1a5 in ATL_dgemm ()
(gdb) info reg
rax 0x7fffec15dd40 140737154243904
rbx 0x2c 44
rcx 0x4fdad00 83733760
rdx 0x24 36
rsi 0x24 36
rdi 0x8 8
rbp 0x4fd4a00 0x4fd4a00
rsp 0x7fffffffb848 0x7fffffffb848
r8 0x24 36
r9 0x4fd4a00 83708416
r10 0x8 8
r11 0x24 36
r12 0x4fdad00 83733760
r13 0x4fd0e80 83693184
r14 0x8 8
r15 0x4fd0e80 83693184
rip 0x7fffec15dd4d 0x7fffec15dd4d <ATL_dupMBmm0_8_0_b0+13>
eflags 0x10206 [ PF IF RF ]
cs 0x33 51
ss 0x2b 43
ds 0x0 0
es 0x0 0
fs 0x0 0
$grep flags /proc/cpuinfo
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 lahf_lm tpr_shadow vnmi flexpriority