Clearing symbol values, removing symbols from memory and general garbage collection.

learn more… | top users | synonyms

43
votes
5answers
21k views

How do I clear all user defined symbols?

Is there some way to do this other than going to Evaluation -> Quit kernel and firing a new one up?
17
votes
4answers
2k views

Elegant manipulation of the variables list

I have a list of global variables (some of them are indexed variables), for example: varsH = Hold[U0[1], U0[2], B0, V0[1], V0[2]] Or (if it is easier to handle) ...
28
votes
5answers
4k views

Clear complains that a subscripted variable is not a symbol or a string?

Here's a small listing where I've used EscqEsc to typeset θ in the notebook: ...
55
votes
2answers
3k views

Is there a way to separate variables between multiple notebooks?

I often correct homework by checking the calculations in Mathematica. Sometimes you would like to have two solutions open at once. However often defined symbols such as ...
10
votes
2answers
2k views

Error entering equation in DSolve

I entered a command incorrectly as follows: DSolve[{y'[x]=y[x]},y[x],x] I am now experiencing: ...
25
votes
3answers
1k views

How to clear parts of a memoized function?

I have a function of two variables, e.g.: f[a_, b_] := f[a, b] = something f[a - 1, b - 1] etc With the above code I used the concept of memoization to speed up ...
1
vote
1answer
546 views

Why my differential equations become True? [duplicate]

I've been trying to solve a system of nonlinear differential equation, but the conditions are a bit weird. Two of the differentials equate to the same equation, but have different boundary ...
13
votes
2answers
2k views

How to unload automatically loaded packages?

I know that this has been discussed here (How do I clear all user defined symbols?), but my case is somewhat different. How does one unload packages during runtime that were loaded with the start of ...
11
votes
2answers
219 views

Good clearing practices

I have been using Mathematica for about 2 years and I'm pretty ok to write and optimize my code. Wanting to improve my practice, I often look at code examples. However, I can not determine if there is ...
16
votes
6answers
2k views

How to clear all variables except one?

I have a lot of variables: $a,b,c,d, \ldots $ I want to clear the values of all of them except $b$. It's really lengthy to write Clear[a]; Clear[c]; ... Is ...
6
votes
1answer
1k views

Clear and Unset doesn't free memory

Example: Try this example only if you have > 4G ram d = 2000; f[x_, y_, d_] = Sum[Subscript[a, i, j]*x^i*y^j, {i, 0, d - 1}, {j, 0, d - i}]; Then ...
3
votes
2answers
163 views

Unset while running recursion

I am trying to run a recursive definition while at the same time clearing previously found values, so my memory is not completely consumed. I found this: How to clear parts of a memoized function? ...
1
vote
1answer
265 views

How to Clear derivative definitions?

I can't find a Clear or ClearAll command that gets rid of Derivative definitions I created. this code: ...