sand15

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These are questions asked by sand15

Hi,

As a notional example those instructions generate 21 variables and around 4 Giga Bytes of data (bottom right of the Maple window ; roughly the same value read from the windows manager)

with(Statistics):
for n from 1 to 10 do
   X__||n := RandomVariable(Uniform(0,1)):
   S__||n := Sample(X__||n, 10^8)
end do:

I want to clean some part of the  memory ; for instance all the S__||n.
The following doesn't work

KeepVars := { seq(X__||n, n=1..10)}:
unassign({anames(user)} minus KeepVars ) ;
gc();


Is there a way to deallocate the memory occupied by some of my user variables ?
 

Hi there,

The command

           dsolve(MyOde, numeric, range=MyRange, method=rosenbrock, output=piecewise)

returns a list of solution pieces which is not sufficiently dense according to how I intend to use it.


Is there a possibility to impose the "number of pieces" or the positions of the "breaks" in this command ?

Thanks in advance for any suggestion.

 

Hi everybody,

 

I want to plot many curves in the form of a table.

For instance, let    p := plot(x, x=0..1, labels=[x*Unit('m'), y*Unit('m')]):

The command   plots:-display(p)  returns a plot  with labels x [[m]] and y [[m]], just as expected.

But the commands (remember I have several plots)
                             plots:-display(<p>);                              # and the generalization plots:-display(<p | p>)
                             DocumentTools:-Tabulate([p]);           # and the generalizationDocumentTools:-Tabulate([p,p])
both provide labels  x Units:-Unit('m') and  y Units:-Unit('m')

Is there a way to fix this and obtain plots withe the expected labels ?

Thank to all of you for yout help

Hi everybody,

I have differential equation of the form eq := diff(x(t), t) = x(t) + 1  and I want to find the name of the dependent variable (more generally this issue concerns a differential system in N dependent variables).

How should I use “indets” in order to obtain {t, x(t)} ?

(indets(eq, name) returns {t}, while indets(eq, function) returns {t, x(t), d/dt x(t)}.

Thanks in advance

Hi everybody,

 

I'm working under Windows 7 

 

My need :
A MAPLE code has to be run from an ECLIPSE session (through a cmaple MyCode).
In this ECLIPSE session the user chooses a data file among many, and ECLIPSE then has to tell MyCode what file it has to read.


The solution I figured out :
Step 1 : ECLIPSE  set an environment variable "DataFile" which contains the user's choice, for instance set MyData=NameOfTheFile
Step 2 : Within MyCode I get the value of MyData from these two commands

MyFile := getenv(DataFile):

readdata(MyFile, …)

 

This doesn't work ( getenv(DataFile) returns [1," "] instead of the desired file name).
In fact it seems that getenv enables access to the “native” environment variables of Windows only (for instance HOMEDIR), not to the user defined environment variables (?)


Is  it possible to fix this and how ?

PS  : I face the same difficulties if I type set MyData=NameOfTheFile directly from a cmd command and try to access the value of MyData from a Maple session


Thanks for your help

 

 

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