Public bug reported: Originally reported in https://bugs.debian.org/906198
The following simple test fails on s390x: ---------------------------8<------------------------------ import numpy as np from scipy.optimize import leastsq y = np.array([0., 1., 1., 2., 1., 1., 0.]) x = np.arange(len(y)) def func(par): return par[2] * np.exp(-(x - par[0])**2/par[1]) - y print(leastsq(func, [0,1,0])) ---------------------------8<------------------------------ The expected result is (array([3. , 4.42280548, 1.67210345]), 1) while on S390x, one gets (array([0. , 1. , 0.34027645]), 3) Further information from https://bugs.debian.org/915738 The bug seems to be a miscompilation of scipy/optimize/minpack/qrsolv.f with -funroll-loops. Removing -funroll-loops is enough to get the leastsq testcase to pass. ** Affects: gcc-8 (Ubuntu) Importance: Undecided Status: New ** Affects: imexam (Ubuntu) Importance: Undecided Status: New ** Affects: python-scipy (Ubuntu) Importance: Undecided Status: New ** Affects: python-scipy (Debian) Importance: Unknown Status: Unknown ** Bug watch added: Debian Bug tracker #915738 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=915738 ** Also affects: python-scipy (Debian) via https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=915738 Importance: Unknown Status: Unknown ** Also affects: imexam (Ubuntu) Importance: Undecided Status: New ** Also affects: gcc-8 (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1811798 Title: gcc 8 miscompiles scipy/optimize/minpack/qrsolv.f To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gcc-8/+bug/1811798/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs