id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
9710 Assumptions not passed to differential equation solver kedlaya burcin "The assume function doesn't seem to work with the differential equation solver, despite what the documentation for desolve suggests. This returns an error:
{{{
sage: x = var('x')
sage: k = var('k')
sage: y = function('y',x)
sage: assume(k>0)
sage: print desolve(diff(y,x,x)+k*y-exp(-k*x),[y,x])
Traceback (most recent call last):
File """", line 1, in
File ""_sage_input_25.py"", line 10, in
exec compile(u'open(""___code___.py"",""w"").write(""# -*- coding: utf-8 -*-\\n"" + _support_.preparse_worksheet_cell(base64.b64decode(""eCA9IHZhcigneCcpCmsgPSB2YXIoJ2snKQp5ID0gZnVuY3Rpb24oJ3knLHgpCmFzc3VtZShrPjApCnByaW50IGRlc29sdmUoZGlmZih5LHgseCkrayp5LWV4cCgtayp4KSxbeSx4XSk=""),globals())+""\\n""); execfile(os.path.abspath(""___code___.py""))
File """", line 1, in
File ""/tmp/tmpyNFGr0/___code___.py"", line 7, in
exec compile(u'print desolve(diff(y,x,x)+k*y-exp(-k*x),[y,x])
File """", line 1, in
File ""/home/kedlaya/sage-complete/local/lib/python2.6/site-packages/sage/calculus/desolvers.py"", line 340, in desolve
soln = maxima(cmd)
File ""/home/kedlaya/sage-complete/local/lib/python2.6/site-packages/sage/interfaces/expect.py"", line 1032, in __call__
return cls(self, x, name=name)
File ""/home/kedlaya/sage-complete/local/lib/python2.6/site-packages/sage/interfaces/expect.py"", line 1451, in __init__
raise TypeError, x
TypeError: Computation failed since Maxima requested additional constraints (try the command 'assume(k>0)' before integral or limit evaluation, for example):
Is k positive, negative, or zero?
}}}
Found by Praveen N. and Aashita during Sage Days 25 coding sprint.
" defect closed major sage-duplicate/invalid/wontfix calculus duplicate differential equations, assumptions robert.marik kcrisman jdemeyer Karl-Dieter Crisman N/A