2019-12-19 16:23:23 +0200 commented question Condition of type: STORAGE-EXHAUSTED After some Googling I have found that it means that the program is using all the memory at disposition. How do I increase the memory limit? 2019-12-19 07:29:19 +0200 asked a question Condition of type: STORAGE-EXHAUSTED While doing some long calculations I got the error: Condition of type: STORAGE-EXHAUSTED What does it mean? How do I get rid of it? 2019-12-18 16:56:05 +0200 received badge ● Student (source) 2019-12-18 11:45:58 +0200 received badge ● Scholar (source) 2019-12-18 11:16:14 +0200 asked a question Substituting variable value I use the following code to calculate the Kretschmann scala of the Schwartzchild spacetime: print("Initialization of manifold, chart, and metric. Definitions of constants.") M=Manifold(4,'M',structure='Lorentzian') X. = M.chart(r"t r:(0,+oo) th:(0,pi):\theta ph:(0,2*pi):\phi") m=var('m') g=M.metric() g[0,0]=-(1-2*m/r) g[1,1]=1/(1-2*m/r) g[2,2]=r^2 g[3,3]=r^2*sin(th)^2 print('Calculating Riemann tensor') R = g.riemann() print(R[:]) uR=R.up(g) dR=R.down(g) print('Calculating Kretschmann scalar') kr= uR['^{abcd}']*dR['_{abcd}'] print(kr.expr())  It works, but now I want to substitute a value for the variable m. I have tried with: kr.substitute(m==10) kr.subs(m==10) kr.substitute_expression(m==10)  but none of these work. How can I make the substituteion m=10? 2019-12-17 21:26:30 +0200 asked a question How do i plot a piecewise function with functional constraints? I have to plot a function T(x,x) which equals xy if xy>0 and x+y otherwise. I have defined the function: def T(x,y): if (x*y>0): return x*y else: return x+y  but it does not work. 2019-12-17 21:26:29 +0200 asked a question How do I define a piecewise function with functional restrictions? I have to define a piecewise function T(x,y) which equals xy if xy>0 and x+y for x*y<=0. How do I do this? I have tried in this way: def T(x,y): if (x>0): return x*y else: return x+y  but it does not work. How can I solve this problem?