Honigmelone

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These are questions asked by Honigmelone

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:=<a,b,c>:

vec(1):=1;    # expected result: a:=1

vec := Vector(3, {(1) = 1, (2) = b, (3) = c})

(1)

a;            # expected result: 1

a

(2)

 

 

Download point_to_element.mw

 

 

Hey,

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

restart:

alias(a=a(t),b=b(t));

a, b

(1)

assume(a(t),real);

getassumptions(a(t));

{((a(t))(t))::real}

(2)

assume(b(t),real);

getassumptions(a(t));

{((b(t))(t))::real}

(3)

getassumptions(b(t));

{((b(t))(t))::real}

(4)

 

 

 

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

alias_bug.mw

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?

 

Thanks in advance!

 

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.

Thanks in advance!

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