segment fault

王栋

unread,

Jun 27, 2017, 5:04:18 AM6/27/17

to CVXOPT

Hi all:

i found a error segment fault when i use cvxopt as follows:

from cvxopt import solvers

print 'pMatrix size is' + str(pMatrix.size)

print 'qMatrix size is' + str(qMatrix.size)

print 'gMatrix size is' + str(gMatrix.size)

print 'hMatrix size is' + str(hMatrix.size)

sol=solvers.qp(pMatrix, qMatrix, gMatrix, hMatrix)

resMatrix = sol['x']

print 'resMatrix size is ' + str(resMatrix.size)

print 'the weights is:'

print resMatrix[0:20]

the print output is:

pMatrix size is(355063, 355063)
qMatrix size is(355063, 1)
gMatrix size is(710116, 355063)
hMatrix size is(710116, 1)

the code give error:

sol=solvers.qp(pMatrix, qMatrix, gMatrix, hMatrix)

the cvxopt version is 1.1.9

anybody can help me?

thanks ahead

Martin

unread,

Jun 27, 2017, 5:07:42 AM6/27/17

to CVXOPT

Thanks for reporting this. Can you provide a minimal example? What platform are you using?

王栋

unread,

Jun 27, 2017, 9:45:10 PM6/27/17

to CVXOPT

the platform is:

Distributor ID: Debian

Description: Debian GNU/Linux 8.7 (jessie)

Release: 8.7

Codename: jessie

在 2017年6月27日星期二 UTC+8下午5:07:42，Martin写道：

王栋

unread,

Jun 27, 2017, 10:10:58 PM6/27/17

to CVXOPT

the matrix is generated dynamically, and some matrix is sparce matrixs,how can i get and save to file?

在 2017年6月27日星期二 UTC+8下午5:07:42，Martin写道：

Thanks for reporting this. Can you provide a minimal example? What platform are you using?

王栋

unread,

Jun 27, 2017, 10:24:05 PM6/27/17

to CVXOPT

i read the document carefully, and get the matrix. please check the attachment, it is named "example.tar.gz", contain 4 matrix i used

在 2017年6月27日星期二 UTC+8下午5:07:42，Martin写道：

Thanks for reporting this. Can you provide a minimal example? What platform are you using?

example.tar.gz

Martin

unread,

Jun 28, 2017, 2:40:26 AM6/28/17

to CVXOPT

Unfortunately I don't know how to read the files that you provided. It would be very helpful if you could provide a minimal, self-contained script (along with your data) that reproduces the error.

王栋

unread,

Jun 28, 2017, 4:20:21 AM6/28/17

to CVXOPT

ok，please check the attachment again.

it can be executed directely

在 2017年6月28日星期三 UTC+8下午2:40:26，Martin写道：

Desktop.rar

Martin

unread,

Jun 28, 2017, 5:51:26 AM6/28/17

to CVXOPT

Your example runs without any issues on my machine (macOS 10.12.5, Python 2.7.12, cvxopt 1.1.9).

A couple of follow-up questions:

Is your OS 32-bit or 64-bit? (arch or uname -m)
Which version of Python are you using? (python -V)
How did you install CVXOPT?

王栋

unread,

Jun 28, 2017, 8:15:30 AM6/28/17

to CVXOPT

thank you.

my os is:

Distributor ID: Debian

Description: Debian GNU/Linux 8.7 (jessie)

Release: 8.7

Codename: jessie

when i run my program on ubuntu ,it is also OK:

Distributor ID: Ubuntu

Description: Ubuntu 16.04.2 LTS

Release: 16.04

Codename: xenial

i guess it is something wrong on Debian.

i use too much time to confirm the program

在 2017年6月28日星期三 UTC+8下午5:51:26，Martin写道：

Martin

unread,

Jun 28, 2017, 9:50:38 AM6/28/17

to CVXOPT

OK. Ubuntu is also based on Debian. My current guess is that either your Debian system is 32-bit and there is a bug in CVXOPT or there is a bug in one of the libraries that CVXOPT links against.

王栋

unread,

Jun 28, 2017, 9:55:09 PM6/28/17

to CVXOPT

my Debian system is 64-bit.

i guess there is a bug in one of the libraries that CVXOPT links against.

thanks for your help again.

在 2017年6月28日星期三 UTC+8下午9:50:38，Martin写道：

王栋

unread,

Jun 28, 2017, 10:59:34 PM6/28/17

to CVXOPT

at another machine, use same ubuntu system, it also get segment fault. the error info is:

Thread 11 "python" received signal SIGSEGV, Segmentation fault.

[Switching to Thread 0x7fffdbbd3700 (LWP 7932)]

0x00007ffff1e64ce0 in dscal_kernel_8_zero ()