## 85 Reputation

5 years, 213 days

## Assigning vector of symbols...

Maple

Hey,

I want to assign a value to a symbol stored in a vector. I know the position of the symbol in the vector. Is there an easy way to do this?

Here to illsutrate my problem:

 > restart:
 > vec:=:
 > vec(1):=1;    # expected result: a:=1
 (1)
 > a;            # expected result: 1
 (2)
 >

## Possible Bug in Maple ...

Maple 18

Hey,

I think I found a bug concerning the useage of assume and alias:

 > restart:
 > alias(a=a(t),b=b(t));
 (1)
 > assume(a(t),real);
 > getassumptions(a(t));
 (2)
 > assume(b(t),real);
 > getassumptions(a(t));
 (3)
 > getassumptions(b(t));
 (4)
 >
 >
 >

Commenting out the alias command produces correct results. I am on linux with build 922027.

alias_bug.mw

## Is there an analog of MATLAB tilde?...

Maple

Hey,

I wonder if there is an operator to skip inputs and outputs of functions. Consider this example:

The output would be:

However my system is much bigger and I only need the second output of the command and I dont want to waste memory on the first.

In Matlab I would write

~,ans := GenerateMatrix(...)Is there a similar shortcut availible in Maple?

## Problem with substitution...

Maple

Hey,

I have an expression like this:

a:= b(t)+diff(b(t),t)+diff(b(t),t\$2)+diff(b(t),t\$3)+...:

I want to substitute diff(b(t),t) with b_symbol_diff. I dont know how many more differentials are in the expression.

If I use subs(diff(b(t),t)=b_symbolic_diff,a)

maple also substitutes in diff(b(t),t\$2). Because b_symbol_diff is not a function of t the higher order differentials are zero.

Is there a way to tell maple not to substitute those expressions that are enclosed in diff()?

I need this because I want to calculate the Jacobian of a vector and VectorCalculus[Jacobian]() does not accept functions.