Hello,

The following problem works if i = j.   I need help to fix this problem for i ≠ j.  Thanks

A := [1, 2, 3, 4, 5];

B := [a, b, c, d];

seq([A[i], B[j]], i = 1 .. 5, j = 1 .. 4);
Error, invalid input: seq expects its 3rd argument, step, to be of type numeric, but received j = 1 .. 4

What is the Maple command to simplify  -x^(a)+x^n  to zero under the assumption that a=n?

I have attempted the following command

simplify(-x^(a)+x^n) assuming a=n;

However, it did not produce zero. The following command however produces zero

subs(a=n,-x^(a)+x^n);

 How to do this operation using assumptions. How to inform Maple to assume that a=n.

Hi,

I'm trying to export a plot using the open maple api but it looks like open maple API doesnt support certain specific features.

Eg. "Export(\"images\\\result1.gif\", plot(sin(x), title = \"The sine function\", thickness = 3, gridlines=true));"

Above works fine when executing in actual maple application (i.e. correctly exports with gridlines) however doing the same via open maple api it does export the chart but not the specified gridlines.

Had the same issue when setting axis options to show log instead of linear. 

Did anyone else get this? Is this a known issue with open maple api? Is there workaround available?

Thanks,

Bidur

I have the following problem consisting of multiple seteps.

I have a vector equation consisting of n equations with n parameters (a[n]). Usually the n <= 15. As example data I will use the case n=4.

equations := Vector[column]([ a[1], a[2], a[3],a[4]])-Vector[column]([ b[1], b[2], b[3],b[4]])=0;

The first thing I want to create is a matrix with a format 2^n x n (here: rows=16 by columns=4). The matrix only consists of ones and zeros which contains all possible combinations of ones and zeros. E.G. for n=4

subsMatrix := Matrix([[ 0 , 0 , 0 , 0 ],[ 1 , 0 , 0 , 0 ],[ 0 , 1 , 0 , 0 ],[ 0 , 0 , 1 , 0 ],[0 , 0 , 0 , 1],[1, 1 , 0 , 0],[1, 0 , 1 , 0],[1, 0 , 0 , 1],[0, 1 , 1 , 0],[0, 1 , 0 , 1],[0,0,1,1],[1, 1 , 1 , 0],[1, 1, 0 , 1],[1, 0 , 1 , 1],[0, 1 , 1 , 1],[1, 1 , 1 , 1]]);

Question 1: How do I create such a matrix for the general case? I have absolutely no idea how to achieve this with Matple

The next thing I want to do is to use the rows as substitution equations for the a[i] values, only if the value of the subsMatrix is 0. E.G. in the first case I want to set a[1]=a[2]=a[3]=a[4]=0, then a[2]=a[3]=a[4]=0, then a[1]=a[3]=a[4]=0, and so forth and save the equation as a new equation

I tried the following:

rows:=RowDimension(subsMatrix);

columns:=ColumnDimension(subsMatrix);

for i from 1 by 1 while  i<=rows do

                 subsEquations[i]:=equations

                 for j from  1 by 1 while  j<=columns do

                     if subsMatrix[i,j] =0 then

                          subsEquations[i]:= subs(a[j]=subsMatrix[i,j],subsEquations[i]) 

                     else      

                          #do nothing if the value in the subsMatrix[i,j]=1

                     end if

                 end do:    

end do:

Question 2: What is my error? Maple says the loop is indeterminate. But I don't see why it is not working.

I would be thankful if someone could help me out. I am open to other kind of strategies to this problem :).

Hi,

I am trying to download some MapleSim Robotic models from the Maplesoft website but I have 'Invalid File Format' error. Could you help please?

Best

Onder

I am trying to do an hourly simulation of a solar-thermal system. The method I am using requires an inital guess for a value which is used in a series of equations. That variable is then back calculated, and checked against the initial guess. If it is too far off, the back calculated value is used as the new guess and so on...

My question is twofold. First, is there a way to create a sort of module that can execute a number of steps when called upon (i.e. the iterative process described above). Second, how can I run this for each hour of the year (the weather inputs for each hour will change) without manually executing each one, one at a time. So far my guess is to make a matrix with the weather inputs for each hour, and then have some sort of loop read the rows (hours) one at a time, pull the data from it, run the series of steps, and then store the output for that hour in a new matrix. Is this the best way to do this? If so, which functions/tools in Maple should I look into that can do this for me?

Thanks.

Hello, I am using PDEtools to evaluate an equation but got system inconsistent in respect of a parameter used after the command map(pdsolve). I am afraid the result sebsequently given may not be correct, did I do something wrong?

Thanks.

test.mw

Hi everybody,

This is a notional example.
I create a variable MyColor of type string, which contains some correct specification of a known color.
Two examples are
    MyColor := "CSS Red";            
    MyColor := "Resene LaRioja":

In the ColorTools package there exist a few couples of (a priori) reciprocal functions, for instance NameToRGB24 and RGB24ToName.
So I can expect that composing one of this function with its reciprocal is a neutral operation.

But, if I apply first  NameToRGB24 to a well formed MyColor color and next thits reciprocal RGB24ToName , I do not recover MyColor ... or at least not all the time


Example 1 : 
with(ColorTools):
MyColor := "CSS Red";    
RGB24ToName ( NameToRGB24 (MyColor) ); 
     "Red"

Let us observe the loss of the palette name ...


Example 2 : 
MyColor := "Resene LaRioja";    
NameToRGB24 (MyColor) ); 
      [179, 193, 16]
RGB24ToName ( % ); 
     error, (in ColorTools) unknown RGB color [179, 193, 16]


It seems that RGB24ToName ( NameToRGB24 (MyColor) ); works correctly only if MyColor refers to a color from palette CSS. This seems consisttent with the loss of the palette name in example 1 and the presence of the word RGB (and not RGB24) in this error message.
More generally, for colors from other palettes than CSS the same kind of error is returned (I did not do intensive testing ...)

Is this an error,
   or some limitation I missed,
      or an improper use of RGB24ToName ?

I look forward to your response

I'm trying to solve vast system of differential equations (Hamiltonian equations of motions). 

I have this kind of error and don't know what to do with it:

Error, (in dsolve) found the independent variables {t} also present in the names of the functions of the system {(cos(varphi(t)))((3333333333/10000000000)/sin(theta(t))^2+(1/23)*cot(theta(t))^2/R(t)^2), (sin(psi(t)))((3333333333/10000000000)/sin(theta(t))^2+(1/23)*cot(theta(t))^2/R(t)^2)}

Here's the file:ClassicalTrajectoriesAr-CO2.mw

 Hi everybody,

Until recently I was using Maple 2015.0 on this PC :

Windows XP
2 dual core proc Intel(R) Xeon(R) CPU E3-1225 V2 ; 3.19 GHz
64 bytes,
16 Go RAM

For two days now I am using Maple 2015.0 on this one

Windows 7
4 dual core proc Intel(R) Xeon(R) CPU 5-2637 V3 ; 3.50 GHz
64 bytes,
64 Go RAM

Comparisons of the running times for exactly the same code, consisting in 10000 independent Monte Carlo  simulations distributed over all the nodes (resp 4 and 8) give :

Windows XP :  504 sec  (with a variation of the order of  +/- 3s for different replicates)

Windows 7   :  343 sec  (with a variation of the order of  +/- 3s for different replicates)

The expected running time should be 504 * (3.2/3.5) * (4/8) = 230 s
(or 504 * (4/8) = 252 s if you neglect the acceleration due to the clock rate)
The realized running time (343 s) is thus at least  40% larger than the expected one.


Does anybody has already observed this kind of performance loss during XP -> 7 migration ?
Are there some comparisons of cpu times between Windows XP and 7 ?


Thank you all for sharing your own experience.



postscript : a NOTIONALexample of how the computations are distributed is given below

NbOfRuns := 10000:

# Data is a Matix(NbOfRuns, NbOfCols, …) constructed elsewhere

NbOfNodes := Grid:-NumNodes():
NbOfRunsPerNode := NbOfRuns / NbOfNodes:
for k from 0 to NbOfNodes do
   FirstData := 1 + k * NbOfRunsPerNode:
   LastData := (k+1) * NbOfRunsPerNode:
   Grid:-Run(k+1, MyCode, [Data[FirstData..LastData, ..], …])
end do:

The code "solve((x+exp(-1))^x = 1, x)"gives the error "Error, (in Engine:-Dispatch) invalid subscript selector". How is this possible?

Hi
I want to solve this integration simbolic:


I use this cammand :

But Maple return this:

Would you Please Help me , thanks

How can I change the color of a graphic tittle?