hello
Why the same code looks ok on sageMathcloud and generates an error on sagemath VM ?
Maybe the way to write the code is not good, but why 2 different results ?
Sage Math Cloud Result Ok
Sage Math VM Code Error
t = var('t') # define a variable t
m = var('m') # define a variable ODE coeff m
b = var('b') # define a variable ODE coeff b
c = var('c') # define a variable ODE coeffc
x = function('x')(t) # define x to be a function of that variable
#
assume(4*c*m+b^2>0)
DES = m*diff(x, t,2) + b*diff(x, t,1) - c*x
ySup=desolve(DES, [x,t])
#
forget()
assume(4*c*m+b^2==0)
DE0 = m*diff(x, t,2) + b*diff(x, t,1) - c*x
y0=desolve(DE0, [x,t])
#
forget()
DEI = m*diff(x, t,2) + b*diff(x, t,1) - c*x
assume(4*c*m+b^2<0)
yInf=desolve(DEI, [x,t])
show(yInf)
show(y0)
show(ySup)
show ("########## Now Latex Code ###########")
latex(yInf)
latex(y0)
latex(ySup)
the error below:
TypeError Traceback (most recent call last)
<ipython-input-1-20eb09c83522> in <module>()
12 assume(Integer(4)cm+b*Integer(2)==Integer(0))
13 DE0 = mdiff(x, t,Integer(2)) + bdiff(x, t,Integer(1)) - cx
---> 14 y0=desolve(DE0, [x,t])
15 #
16 forget()
/home/sage/sage-7.6/local/lib/python2.7/site-packages/sage/calculus/desolvers.pyc in desolve(de, dvar, ics, ivar, show_method, contrib_ode)
455 # we produce string like this
456 # ode2('diff(y,x,2)+2*'diff(y,x,1)+y-cos(x),y(x),x)
--> 457 soln = P(cmd)
458
459 if str(soln).strip() == 'false':
/home/sage/sage-7.6/local/lib/python2.7/site-packages/sage/interfaces/interface.pyc in __call__(self, x, name)
243
244 if isinstance(x, six.string_types):
--> 245 return cls(self, x, name=name)
246 try:
247 return self._coerce_from_special_method(x)
/home/sage/sage-7.6/local/lib/python2.7/site-packages/sage/interfaces/interface.pyc in __init__(self, parent, value, is_name, name)
671 self._name = parent._create(value, name=name)
672 except (TypeError, RuntimeError, ValueError) as x:
--> 673 raise TypeError(x)
674
675 def _latex_(self):
TypeError: Computation failed since Maxima requested additional constraints; using the 'assume' command before evaluation may help (example of legal syntax is 'assume(b>0)', see assume? for more details)
Is b zero or nonzero?
