Dear Community,

How could I specify a list of random colors using some kind of an RGB function, which then could be used in another command for coloring? I think of something like this:

myColors := [ seq( RGB ( [rint(0,255) , rint(0,255) , rint(0,255)] ) , j = 1 .. 20 ) ] :

which does not work of course :-)  This should produce me a list of 20 random colors.  What would be the right RGB color function?

Tx for the kind help in advance

best regards

Andras

Dear Community,

I generate two vectors and try to plot them one vs. the other ( ZPLOT vs. PREDS )  with the pointplot command. Unfortunately I get the message "points are not in the correct format" ... Probably a minor error, but it is unclear what format Maple expects here? What do I do wrong?

Tx. for the kind help in advance,

best regards

Andras

P.S. Maple file attached

Z_DAK_PROC.mw

Hello people in mapleprimes,

I tried to solve y=x^3 for x, expecting of getting a result of x^(1/3),

through using restart;assume(x::real,y::real);
b:=y=x^3;
solve(b,x);

But, the result was:

Warning, solve may be ignoring assumptions on the input variables.
             (1/3)    1  (1/3)   1    (1/2)  (1/3)  
            y     , - - y      + - I 3      y     ,
                      2          2                  

                1  (1/3)   1    (1/2)  (1/3)
              - - y      - - I 3      y     
                2          2                

.

It means that solve couldn't use the assumption of x and y being real.

On the other hand, reading RealDomain package, y^(1/3) is returned properly:

with(RealDomain):
solve(b,x);
                              (1/3)
                             y     

What I want to ask you is

Aren't there ways other than using the RealDomain package, to obtain the solution of y^(1/3)?

I will be very glad if you give me answers.

Best wishes.

taro

Hi,

I'm new to the physics package - wondering if i can tweak it a bit to look like things i'm used to:

is there a way to make Christoffel symbols print as upper case gamma, instead of  'G'?

KroneckerDelta print as lower case delta, instead of 'd'?

can i make the Schwarzschild metric look like it does in Hartle, Carroll, and others:

-(1 - 2M/r)dt^2 + (1-2M/r)^-1 + r^2(dtheta^2 + sin(theta)^2 dphi^2)

i know about setting the signature in Setup.

i have tried the 'Coordinates' command, but when i give it X=[t,r,theta,phi] i always seem to get back

[t,r,q,f]

i am running maple 2016

many thanks,

larry

Hello everyone,
I would like to get a symbolic result of each variable x,y and z for the following 3 nonlinear equations. Maple does not respond to the following code at all. (Not even an error report.)

restart;

eq1 := x^2+y^2+z^2-134*x+800*y-360*z+31489, 2;
eq2 := x^2+y^2+z^2-934*x+900*y-370*z+321789, 2;
eq3 := x^2+y^2+z^2-614*x+1350*y-1110*z+70048, 97;
solve({eq1, eq2, eq3}, {x, y, z});

Thanks in advance.

P.S: Afterwards my intention is to solve these equaitons numerically for different variable values, and transfer to MatLab in order to plot animations and graphs. 

     It is known that ODE boundary value problem is similar to the problem of solving systems of nonlinear equations. Equations are the boundary conditions, and the variables are the values of the initial data.
For example:

y '' = f (x, y, y '), 0 <= x <= 1,

y (0) = Y0, y (1) = Y1;

Where y (1) = Y1 is the equation, and Z0 is variable, (y '(0) = Z0).

     solve () and fsolve () are not directly suitable for such tasks. Directly should work the package of optimization in relation to a system of nonlinear equations. (Perhaps it has already been implemented in Maple.)
Personally, I am very small and unprofessional know Maple and cannot do it. Maybe there is someone who would be interested, and it will try to implement this approach to solving ODE boundary value problems?  

I am trying to find a download for the ONEOptimal package for Maple (http://iopscience.iop.org/article/10.1088/0253-6102/61/2/03). I read the article but there is no download link to the file. Does anyone know where I can download the package?

I have a system of equations e.g.

A^2+B*A+C=0

where A,B,C are Matrices and I want to solve for A.

Sure I can write every equations in brakets [..=0], but isn'T it possible to just use the matrix notation?

I've been trying to numerically solve (and plot) this equation. Maple tells me that some matrix is singular - I have no idea, what I can do.

eq := diff(y(x), `$`(x, 3))-(diff(y(x), x))*(diff(y(x), x))+1 = 0;

cond := (D(y))(0) = 0, (D(y))(1) = 1, ((D@@2)(y))(0) = 0

de := dsolve({cond, eq}, y(x), numeric);

Error, (in dsolve/numeric/bvp) matrix is singular

How I can found stabilty of system by Routh, Jury, Liapunov, Nequist on maple?

The array is:

N := vector (20, x -> y[x]);

The maple creat the array

The other is:

N := vector (20, x -> y[x]);

Where y[x] are a list 

I do plot 

plot( M,N);

But the plot is many lines with the value of the array, i want the fist coordenates of the N with fist coordenate for the M in points or line.

Thanks 

Hi Maple community

I'm running an algorithm where a non-linear equation system must be solved, in this case is a 26x26 system.

After 16116 succesful previous computations, fsolve stops giving me results.
I checked why and I was first expecting that, for some reason, the 26x26 system had an error and I ended with something like 25x26 or vice versa. But that was not the case.

So I tried the command solve and it not only worked fine but also gave me two results, but I only need one. I guess I could check for the wrong solution and discard it, but I still wondering why fsolve is failing and if there is anything to help fsolve not to fail.

These are the set of equations if somebody wants to check them:

EQ[16117][1] := W[1, 16117]*(-0.3860115660e-1*HRa[1, 16117]-0.1876793978e-1*ga[1, 16117]+0.7836678184e-1) = 2.040147478*10^6*SR[1, 16118], W[1, 16117]*(-0.3915554290e-1*HRa[1, 16117]-0.1903748329e-1*ga[1, 16117]+0.8260795999e-1) = 3.876387504, W[1, 16117]*(-0.1876794098e-1*HRa[1, 16117]-0.9892449327e-2*ga[1, 16117]+0.3810204607e-1) = 2.040147478*10^6*v[1, 16118], HLa[1, 16117] = .9724029753*ga[1, 16117]+HRa[1, 16117], NRa[1, 16117] = 0.7006679273e-1*HRa[1, 16117]-.1803623678*ga[1, 16117]+1.002451672, NLa[1, 16117] = 0.7006679273e-1*HRa[1, 16117]+.2484955248*ga[1, 16117]+1.002451672, SL[2, 16118] = SR[1, 16118], fra[1, 16117] = HRa[1, 16117]-HLa[2, 16117], fra[1, 16117] = .25*NRa[1, 16117]+.25*NLa[2, 16117], ga[1, 16117] = 0.;

EQ[16117][2] := W[2, 16117]*(-0.3860115660e-1*HRa[2, 16117]-0.1876793978e-1*ga[2, 16117]+0.7836678184e-1) = -2.040147478*10^6*SL[2, 16118]+7.152482840, W[2, 16117]*(-0.3915554290e-1*HRa[2, 16117]-0.1903748329e-1*ga[2, 16117]+0.8260795999e-1) = 3.876387504, W[2, 16117]*(-0.1876794098e-1*HRa[2, 16117]-0.9892449327e-2*ga[2, 16117]+0.3810204607e-1) = -1.983845478*10^6*SL[2, 16118]+5.221405977, HLa[2, 16117] = .9724029753*ga[2, 16117]+HRa[2, 16117], NRa[2, 16117] = 0.7006679273e-1*HRa[2, 16117]-.1803623678*ga[2, 16117]+1.002451672, NLa[2, 16117] = 0.7006679273e-1*HRa[2, 16117]+.2484955248*ga[2, 16117]+1.002451672, SL[3, 16118] = 0.3505865589e-5, fra[2, 16117] = HRa[2, 16117]-HLa[3, 16117];

EQ[16117][3] := W[3, 16117]*(-0.3860115660e-1*HRa[3, 16117]-0.1876793978e-1*ga[3, 16117]+0.7836678184e-1) = -2.040147478*10^6*SL[3, 16118]+10.82168541, W[3, 16117]*(-0.3915554290e-1*HRa[3, 16117]-0.1903748329e-1*ga[3, 16117]+0.8260795999e-1) = 3.876387504, W[3, 16117]*(-0.1876794098e-1*HRa[3, 16117]-0.9892449327e-2*ga[3, 16117]+0.3810204607e-1) = -1.983845478*10^6*SL[3, 16118]+8.751240594, HLa[3, 16117] = .9724029753*ga[3, 16117]+HRa[3, 16117], NRa[3, 16117] = 0.7006679273e-1*HRa[3, 16117]-.1803623678*ga[3, 16117]+1.002451672, NLa[3, 16117] = 0.7006679273e-1*HRa[3, 16117]+.2484955248*ga[3, 16117]+1.002451672, SL[4, 16118] = 0.5304364281e-5, fra[3, 16117] = HRa[3, 16117];

And after these the solving command that I used was:

SOL[j]:=fsolve({seq(EQ[j][n],n=1..N)},indets({entries(EQ[j],nolist)},assignable(name)));

Which returns

SOL[j]:=

As I said, then I tried the solve command:

SOL[j]:=solve({seq(EQ[j][n],n=1..N)},indets({entries(EQ[j],nolist)},assignable(name)));

which returns:

SOL[16117] :=

{HLa[1, 16117] = 1.011251860, HLa[2, 16117] = .5007913055, HLa[3, 16117] = -0.4240068535e-1, HRa[1, 16117] = 1.011251860, HRa[2, 16117] = .8728245835, HRa[3, 16117] = .2686716410, NLa[1, 16117] = 1.073306847, NLa[2, 16117] = .9685353734, NLa[3, 16117] = .9417827567, NRa[1, 16117] = 1.073306847, NRa[2, 16117] = 1.132612831, NRa[3, 16117] = 1.078974668, SL[2, 16118] = 0.1737463747e-5, SL[3, 16118] = 0.3505865589e-5, SL[4, 16118] = 0.5304364281e-5, SR[1, 16118] = 0.1737463747e-5, W[1, 16117] = 90.12372195, W[2, 16117] = 69.57451714, W[3, 16117] = 49.58407210, fra[1, 16117] = .5104605550, fra[2, 16117] = .9152252689, fra[3, 16117] = .2686716410, ga[1, 16117] = 0., ga[2, 16117] = -.3825916698, ga[3, 16117] = -.3199006320, v[1, 16118] = 8.447574110*10^(-7)},

{HLa[1, 16117] = 3.043461992, HLa[2, 16117] = 2.386862361, HLa[3, 16117] = -0.4240068535e-1, HRa[1, 16117] = 3.043461992, HRa[2, 16117] = 1.087485894, HRa[3, 16117] = .2686716410, NLa[1, 16117] = 1.215697293, NLa[2, 16117] = 1.410701230, NLa[3, 16117] = .9417827567, NRa[1, 16117] = 1.215697293, NRa[2, 16117] = .8376385519, NRa[3, 16117] = 1.078974668, SL[2, 16118] = 0.2032780481e-5, SL[3, 16118] = 0.3505865589e-5, SL[4, 16118] = 0.5304364281e-5, SR[1, 16118] = 0.2032780481e-5, W[1, 16117] = -106.0268094, W[2, 16117] = 265.7250566, W[3, 16117] = 49.58407210, fra[1, 16117] = .6565996307, fra[2, 16117] = 1.129886580, fra[3, 16117] = .2686716410, ga[1, 16117] = 0., ga[2, 16117] = 1.336253076, ga[3, 16117] = -.3199006320, v[1, 16118] = 9.883410782*10^(-7)}

Thanks in advance for any recommendations and suggestions.
 

Hi,

I did some hypothesis testing exercises and I cross checked the result with Maple. I just used following vectors for an unpaired test

a := [88, 89, 92, 90, 90];
b := [92, 90, 91, 89, 91];

I ended up with the following solution:

HFloat(1.5225682336585966)
HFloat(-3.122568233658591)
for a 0.95 confidence interval.

Using

TwoSampleTTest(a, b, 0, confidence = .95, summarize = embed)

and

TwoSampleTTest(a, b, 0, confidence = .975, summarize = embed)

I get following results:

-2.75177 .. 1.15177

-3.13633 .. 1.53633

respectively. I can not explain the discrepancy.

Best regards,

Oliver

PS:

Maple Code in case files won´t be attached.

Unpaired t Test
restart;
Unpaired test-test dataset
a := [88, 89, 92, 90, 90];
b := [92, 90, 91, 89, 91];
The se² estimate is given by:
se²=var(a)+var(b)+2*cov(a*b)=var(a)+var(b)
se²=
sigma[a]^2/Na+sigma[b]^2/Nb;
with Na, Nb being the length of vector a and b respectively.
                             2                              2
  sigma[[88, 89, 92, 90, 90]]    sigma[[92, 90, 91, 89, 91]]
  ---------------------------- + ----------------------------
               Na                             Nb             
sigma[a]^2;
 and
sigma[b]^2;
 are approximated by
S[a]^2;
 and
S[b]^2;
                                             2
                  sigma[[88, 89, 92, 90, 90]]
                                             2
                  sigma[[92, 90, 91, 89, 91]]
                                           2
                    S[[88, 89, 92, 90, 90]]
                                           2
                    S[[92, 90, 91, 89, 91]]
with
S[X]^2;
 defined as
S[X]*`²` = (sum(X[i]-(sum(X[j], j = 1 .. N))/N, i = 1 .. N))^2/N;
                                 2
                             S[X]
                                                 2
                      /      /         N       \\
                      |      |       -----     ||
                      |  N   |        \        ||
                      |----- |         )       ||
                      | \    |        /    X[j]||
                      |  )   |       -----     ||
                      | /    |       j = 1     ||
                      |----- |X[i] - ----------||
                      \i = 1 \           N     //
             S[X] ￂﾲ = ----------------------------
                                   N              
with(Statistics);
Sa := Variance(a);
                   HFloat(2.1999999999999993)
Sb := Variance(b);
                   HFloat(1.3000000000000003)
Now we are ready to do hypothesis testing (0.95).
We have (with k=min(Na,Nb)=5):
C = mean(a)-mean(b); Deviation := t_(alpha/a, k-1)*se(Sa/k-Sb/k);
c := Mean(a)-Mean(b); deviation := 2.776*sqrt((1/5)*Variance(a)+(1/5)*Variance(b));
                  HFloat(-0.7999999999999972)
                   HFloat(2.3225682336585938)
upperlimit := c+deviation; lowerlimit := c-deviation;
                   HFloat(1.5225682336585966)
                   HFloat(-3.122568233658591)

Execution of built in student test
TwoSampleTTest(a, b, 0, confidence = .95, summarize = embed);

How can I modify the appearance of the arrowheads on the vectors displayed in phaseportrai? In particular, how can I "fill in" the arrowheads so that the arrowhead is not just an outline?

My code is:

phaseportrait([D(x)(t)=-0.4*x(t)+(0.5+4*x(t))*y(t),D(y)(t)=0.4*x(t)-(4.5+4*x(t))*y(t)],[x(t),y(t)],t=0..100,[[x(0)=1,y(0)=0.0]],x=0..1,y=0..0.1,stepsize=0.01,scaling=UNCONSTRAINED,linecolour=BLACK,dirgrid=[17,17],linestyle=1,arrows=SLIM,axes=BOXED);

Thank you

Hi evrey ones in pdsolve we have these commande to use U(x,t) 

> U:= subs(pds:-value(output=listprocedure), u(x,t));

  id like to get du(x,t)/dt

i tried these  

U:= subs(pds:-value(output=listprocedure), du(x,t)/dt);  but is not work 

thank you