Hi there! I am having lots of fun with sage. Thank you everyone!
But now I am faced with a SegFault during substitution of symbolic variables. I found a simple workaround but I would like to report the problem anyway. Maybe it was patched already, although I found the same SegFault on sage-4.6.2 and sage-4.7.1. The first version I compiled myself on OS X 10.6.8 and the second I downloaded as package. I was narrowed the problem down to the substitution. The symbolic equations are rather long, therefore I am attaching a link (my public on dropbox) for the sobj with the symbolic list of equations: http://dl.dropbox.com/u/29028094/sys_equ.sobj This script should trigger the error: --script-- sage: sys_equ = load('sys_equ') # see sys_equ.sobj sage: sys_equ[0].variables() #(V, alpha1, alpha2, c, y_0, y_1, y_2, y_3, y_4, y_5, y_6, y_7, y_8, y_9) sage: var('V,alpha1,alpha2,c') #(V, alpha1, alpha2, c) # Workaround: Step-by-step substitution it works... sys_equ_reduced = [eq.subs(c=0.) for eq in sys_equ] sys_equ_reduced = [eq.subs(alpha1=1e-3) for eq in sys_equ_reduced] sys_equ_reduced = [eq.subs(alpha2=1.03) for eq in sys_equ_reduced] sage: sys_equ_reduced[0].variables() #(V, y_0, y_1, y_2, y_3, y_4) # c=0 canceled-out y_5,6,7,8,9 state variables # **** Here comes the trouble **** # Substitution breaks down if I do them at the same time... sys_equ_reduced_fault = [eq.subs(c=0., alpha1=1e-3, alpha2=1.03) for eq in sys_equ] --end script-- --- For the last command I got: ------------------------------------------------------------------------ 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. ------------------------------------------------------------------------ /Users/guilherme/sage-4.7.1/local/bin/sage-sage: line 301: 13128 Segmentation fault sage-ipython "$@" -i If I run under 'sage -gdb' it returns: --- Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000010 0x00000001078e03fe in GiNaC::power::compare () (gdb) --- I could only go this far. If any of you developers need further details I will be happy to provide... Regards, Guilherme -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
