In working on an answer to a recent question on MaplePrimes:
http://mapleprimes.com/questions/210948-Can-We-Trust-Maple

I noticed that in solving a "simple" system of two equations in two unknowns, potentially undesirable expansion occurs.
The two equations were only simple in the sense that the solving was very trivial, since the two unknowns occurred (almost) already isolated on the left:
eq1:=diff(x(t),t)=rhs1;
eq2:=1.2345*diff(v(t),t)=rhs2; #rhs2 is very complicated in the link given.
So in isolating I tried:
solve({eq1,eq2},{diff(x(t),t),diff(v(t),t)});
The resulting ode system took considerably longer to solve numerically than an unexpanded version.
It is trivial (of course) to do the solving without solve in this case.

Here is an extremely simple example, where the unknowns are already isolated, so that the equations themselves are actually the solution.

restart;
eq1:=a=b*(c+d);
solve(eq1,a); #No expansion
eq2:=e=b*(c+d)+f*(8+k);
solve({eq1,eq2},{a,e}); #Expanded:
                   {a = b*c+b*d, e = b*c+b*d+f*k+8*f}

Can expansion be avoided?

So, I am working in a partial differeital equations course and we are doing image processing. I am taking an image and pixel by pixel applying the heat equation to smudge out noise. I created a for loop for the equation and it works, I need to itterate it over and over again. Here is my code:

for t from 1 to 20 do    

for j from 2 to 149 do

for k from 2 to 149 do  

`tile2__j,k`:=dellT/(h^(2))*(`tile__j+1,k`-4*`tile__j,k`+`tile__j-1,k`+`tile__j,k-1`)+`tile__j,k`  

 end do

end do  

for m from 2 to 149 do

for n from 2 to 149 do  

`tile__m,n`:= `tile2__m,n`  

end do

end do  

t := t+1  

end do

Sorry, I could not get the Maple Math editor to work so I just copied my code. Apologize. I keep getting the error "Error, Invalid loop statement termination." Help?

I am examining the curve given by

y=R(x/L)^n

When I put this in and assign a number to any one variable, Maple always returns

y=0.8660254038

I have tried changing the names of the variables, unnassigning variables, restarting Maple, etc. but I cannot plot a function of y with x, I always get y=0.8660254038, even with only one variable assigned to a value.  I am using the student version of Maple 17.

Thanks,

David

Does anyone know how to do crossover between block of binary number?

Example :

If I have 4 blocks, [0011001],[0011100], [0101010], and [1001110].

the first block will crossover with the second block, the second block will crossover with the third block, the third block will crossover with the last block and the last block must crossover with the first block. 

I had tried the code as below. 

for i from 1 to 4 do

for j from 1 to 7 do

block[i][j]:=block[i+1][j];

end do;

new_block[i]:=block[i];

end do;

The problem is the crossover can be done from 1 with 2, 2 with 3 and 3 with 4. But this code unwork for crossover for last block with the first block. Can someone help me? thank you in advance.

Hi,

I have a linear mathematical model that is in deterministic form, but actually one of the input parameters has a stochastic nature and follows a log normal distribution function. and I need to include this in the formulation. Please help me with this questions:

1) Do I need to use stochastic programming methods to solve it? if yes, how?

2) How can I include the distribution function in my model?

3) Can I solve the these kinds of problems using Maple?

How to random generate 2 integer number with condition x must be less than y ?

I had tried the coding below. But the output shown not what i want.

x:=RandomTools[Generate](integer(range=1..7);

y:=RandomTools[Generate](integer(range=1..7);

if x>= y then x:=RandomTools[Generate](integer(range=1..7); y:=RandomTools[Generate](integer(range=1..7); end if;

Example:

I get x:= 5 , y:=1, then i need to regenerate the value of x and y using the last statemet above. but the problem is sometime i might still get the value of x>= y for example on second generate x:3, y=2. I need a code that x and y must be regerate until it get x<y. Can someone help ? Thank you in advance.

How difficult is it to simulate gravitational influences and perturbing effects on celestial orbits with Maple? Could this syntax http://www.maplesoft.com/applications/view.aspx?SID=4484&view=html be altered without excessive changes to consider these aspects?

Are there somewhere worksheets to take a look at as an introduction and to see how such goals would be approached and implemented?

Some time ago, I have used the Virtual 3D Solar System code to plot a few interesting figures with asteroids. It can be found here: http://www.maplesoft.com/applications/view.aspx?SID=4484&view=html . I plotted the asteroid belt as a closed, warped surface according to how the asteroids are inclined, with the arguments of perihelion and longitude of ascending node where they cross the equatorial plane to the other celestial hemisphere. The plot was only done with axes in units of distances, for convenience's sake in astronomical units of 1 AU = 150 million km.

But I am strongly wondering if it were somehow possible to alter or adjust the code such that there is a zylinder placed around such plot where one can see celestial coordinates (Rectascension, Declination) on the inside, so that if one wants to know what coordinates an orbit of a specific asteroid has that one can look in the chart and go out on the balcony and set the telescope to these coordinates. Of course the asteroid most likely is not there on his entire orbital path, but you have at least the location where the asteroid CAN be. Would this be possible to plot?

This probably doesn't work if a closed cylinder is placed around the Virtual Solar System. But how about scrolling the cylinder and the orbits flat on a 2D plot?

Hello,

I am using algorithmic variables to generate questions about the greatest common divisor of two integers.

Unforuntately the integers come out as 1,664 instead of simply 1664 (for example). How can I change the format to the simple version ?

Thanks for your help!

Elisabeth

hello dear,

I was intersted in finding Weyl scalars for a given metric, would be really helpful if anyone can give me an example of how to find a Weyl Scalar for a given metric or set of null tetrads using Debever formalism in Tensor package(more specifically, how to define h in debever formalism for a given set of null tetrad or for a given metric).

Regards,
Suresh

hello,
I try to draw together point (0,0,12) and the line  x=4t, y=-2t, z=2t on one graph 3D. Somebody has some pointers? Thank you 
Agnieszka

Dear all

I have such an expression in the file (test.mw). Obviously it is not a simple form. 10⁹ should be cancelled both in denominator and nominator. I have applied the function simplify(). However, it doesn't work.  I hope someone can do me a favor. That will help me a lot. Thanks

I am solving a complicated ODE and I would like to know if there is a way for Maple to output the ODEs without doing any numerical substitutions for known parameters. Say one of my parameters, call it P, is initialized (there are many more but Ill just simplify and consider one here) to a value of 10. In order to chekc that I have coded the ODEs correctly it would help me if Maple does not substitue with the numerical value 10 for P when displayng teh ODEs, but rather keeps P, as a parameter. Is there a way to achieve this?

hi.please help me for solve algebric equations below?

solve or fsolve dos not any answer?

i think use Newton  Raphson, because solve or fsolve not work.

thankscomparision.mw

Download comparision.mw

if three particles set into 3 energy states ( each values of energy states 0 , e, 2e)

how to calculate P in each configuration by a particle that follows boson and f-b

thank you