564 Reputation

16 years, 358 days

evaluate exponential with some unknown a...

Maple
It seems the exponential function needs all arguments in order to be evaluated: a := .2*exp(A[1, 1]+A[1, 2]); A[1, 1] := 2; evalf(a); 0.2 exp(2. + A[1, 2]) However, I would like to be able to see Maple evaluate as much as it can, ie, the above command should give: 1.4778*exp(A[1,2]) Where 0.2 was multiplied by exp(2), and the rest of the exponential was left symbolic. Is there a way to force maple to do this without having to manually factor anything ? Thanks

Maple's calculations are non-determinist...

Maple

Hello,

I've performed the exact same calculation (using the exact same worksheet, with absolutely no changes made) last night and today and got these results:

y=[0, .4646313991, .9499094532, .5799050874, .1092604065, .4031507404, .8483735670, .6138799333, .1913933456, .3724618402, .7707837830];

y=[0, .4646313991, .9499094532, .5799050874, .1092604061, .4031507404, .8483735643, .6138799354, .1913933461, .3724618343, .7707837938];

Which are exactly the same modulo the last 3 digits.

Digits=10 in both cases.

clear variable from MEMORY...

Maple

Hello,

I found this on a website:

------------------------------------------------------------------------------------------------------------------

restart;

This will clear all values, unload all packages, and reinitialize Maple. However, this command will not free up memory previously allocated to Maple; consequently, when doing large jobs, the only way to improve speed is to exit and restart Maple.

------------------------------------------------------------------------------------------------------------------

Does this mean I can't clear any variables from memory at all without closing Maple?

In Matlab all you have to do is:

clear('x')

and that will clear the variable x from memory (you can see that the amount of memory allocated to Matlab goes down if you look at the windows task manager)

In Maple when I clear the variable x by applying the command:

x:='x'

the amount of memory allocated to maple remains the same.

I'm hoping that that website was wrong and there is a way around this because being able to clear a huge variable that's only needed for the initial stages of a long computation is extremely important - any software should be able to do this.

adding arrays that aren't defined as mat...

Maple

Hello,

If I define two arrays in the following way:

for i from 0 to 2 do

for j from 0 to 2 do

A[i,j]:=[i+j]:

B[i,j]=[i-j]:

od: od:

Then if I try to add them and look at the 0,0th component of the result:

C:=evalm(A+B):

C[0,0];

I don't get an answer. (I've tried both the LinearAlgebra package and the linalg package.

What would I have to do to get them to add successfully ?

Thanks

discretize function into matlab array...

Maple

Hello,

If I have a function:

f(x):=x^2:

And I want

The array: f(x-y) for all x & y  from 0 to 2 with stepsize 0.5

in the same format that matlab stores saved arrays (in a .mat file), is that possible ??

Basically, I would like to be able to open matlab and load an array called 'f' 'from a file generated from maple, such that when I'm in my matlab workspase and type:

f

I get:

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