Numeric.mw

Is there an iterative solver for numeric equations. I'm trying to solve for Iarc & Rarc knowing C and Z1, Z1 can be complex.

Dears,

I have seen a Mathematica code which I would like to have it in Maple, since I do not know that program. Let f(z) an analytic function, say f(z):=1+2^{z+1}+3^{z}. To find the roots of f(z) in a regingion, we can use in Maple the command "Analytic" (of the package "RootFinding"). However, in Mathematica is used the following:

L = 20; Monitor[zeros = Flatten@Table[N[z /. Solve[f[z] ⩵ 0 && k L ≤ Re[z] ≤ k L + L && -10 < Im[z] < 10, z], 25],{k, 300}],k];

What means the "N[z/. Solve..." instruction? Also, the following command:

SortBy[zeros, Re]; 

Can be "translated" to Maple?

Many thaks in advance for your comments!

With Regards,

G.

I run two small computations to test the improvement that should occur when using several cores (8 cores in my computer):

N:=100000.:

st:=time():

w:=seq(sqrt(i),i=1. ..N):

time()-st;

and:

with(Threads):

st:=time():

w:=Seq(sqrt(i),i=1. .. N):

time()-st;

And the results are: 23.6 sec with seq, and 118.4 sec with Seq!

Seriously?

How can these results be explained?

Thank you in advance

I do long "for loops" which perform the same procedure with different inputs and collect the outputs in a vector. In Matlab I use the command "parfor" to accelerate the calculations.

What is the equivalent of "parfor" in Maple? 

An example would be useful.

Thank You

hey everyone
i got a little problem here i really dont get it why my fsolve give me this error

Error, (in sqrfree) argument must be a polynomial or a rational function in {cf[-2], cf[-1], cf[0], cf[1]}
these are my variables :

cf[-2], cf[-1], cf[0], cf[1]}

thats part of my code :

res1;
(34.30563197 cf[-1] - 10.13498047 cf[0] + 5.197134649 cf[1]

   - 0.4714805434) (0.3095515346 cf[-2] + 0.3822521253) - (cf[-1](2.466022067

  ) + cf[0](-0.6605923783) + cf[1](1.076415647))^2

   - cf[-1](2.466022067) - cf[0](-0.6605923783)

   - cf[1](1.076415647) - 333.1166471 cf[-1] + 186.8672744 cf[0]

   - 128.6145289 cf[1] + 0.8737683108, (-39.73727883 cf[-1]

   + 26.25682759 cf[0] - 7.289811219 cf[1] - 0.3506934780)

  (0.4161980514 cf[-1] + 0.4402863507) - (cf[-1](0.3227083347)

   + cf[0](2.517826949) + cf[1](-0.7889944208))^2

   - cf[-1](0.3227083347) - cf[0](2.517826949)

   - cf[1](-0.7889944208) - 15.03436409 cf[-1]

   - 129.5665191 cf[0] + 68.25827819 cf[1] + 0.5888637790,

  (17.36111111 cf[-1] - 29.80788311 cf[0] + 17.36111111 cf[1]

   - 0.2500000000) (0.5000000000 cf[0] + 0.5000000000)

                                                            2
   - (cf[-1](-1.833333334) + cf[0](0.) + cf[1](2.333333334))

   - cf[-1](-1.833333334) - cf[0](0.) - cf[1](2.333333334)

   + 38.17276297 cf[-1] + 34.00261850 cf[0] - 77.23526300 cf[1]

   + 0.3750000000, (-3.548332053 cf[-1] + 12.78057007 cf[0]

   - 19.34221012 cf[1] - 0.1707008416) (0.5290914191 cf[1]

   + 0.5597136492) - (cf[-1](1.060931345) + cf[0](-1.540306477)

   + cf[1](-0.2297630675))^2 - cf[-1](1.060931345)

   - cf[0](-1.540306477) - cf[1](-0.2297630675)

   - 20.59209188 cf[-1] + 28.27859544 cf[0] + 40.45630289 cf[1]

         -10                      
   + 1 10    cf[-2] + 0.2254717519

fsolve({seq(res1[v] = 0, v = 1 .. 2*N+2)})     ( N here is 1 )

why i cant get the awenser and if you can plz solve it for me

i would be happy that anyone can give me an explanation with details

tnX a lot

Arian
 

I'm trying to figure out how to plot the following: if I have a region G in R^2, and two functions f <= g on G, I would like to plot the projection on the XY-plane in say one colour and the volume between f and g in another. For example, consider G the region between the parabolae y=x^2 and y=2-x^2, and f(x,y) = x+y+4 and g(x,y) = 25-x^2-y^2, just to name something. I'd also prefer the plot to be easy adaptable to other functions, e.g. with a different region G, different function descriptions for f and g but also, if possible, projection on one of the other two coordinate planes. Is there an easy way to do this?

I wonder - would it be possible to automate the following way of adding a legend to plots? If so - how?

plot([f(x), g(x), 7], legend = ['f(x)' = f(x), 'g(x)' = g(x), y = 7]);

In my opinion such a legend makes the plot much more readable - but most students (and others) will usually be too lazy to type this out, hence the wish for it be to automated.

Any help will be much appreciated.

Hello,

I would like to ask you for a help with solving a differencial equations for oscillator damped by a constant friction force (no damping force proportional to the velocity!)

General solultion:

Where 

The amplituce A is decreasing by C at each turning point and center of the ascillatory motion moves: x = -C/2 or x = C/2

Moving:

where

How to create a graphic output of movement according to equation x(t) similar to graph mentioned below?

Thank a lot for your help. I have been working on this task for several weeks without success.

Tom

Hi,

Although i can evaluate speed, displacement and accelleration, i can't plot these functions.

The error message is:

What am i doing wrong in my definitions?

Thank you in advance.

Download Berechnungen.mw

Hi,

I am wondering how we can edit a diagram plotted in maple. for example in editdiagram.mw I want name tips of diagram as "a", "b",.... and write them besides the tips on diagram.

Another question is how we can make color different parts of a single diagram by various colors? for example in above diagram we want make blue vertical line, make green horizontal line and make black the curve line?

Thanks a lot

In Maple 2017.2:

solve(x^3+x*a+2 > 0, [a, x]);
           [[a = -3, x < 1, -2 < x], [a = -3, 1 < x]]

solve(x^4+x*a+1 > 0, [a, x]);
Error, (in rootbound) 1st argument must be a polynomial with numeric coefficients

The first one clearly doesn't give the complete set of solutions. It can be made to work by adding conditions on a such as a>0.

I'm not sure if symbolic operations take index=real[i] into account or just silently ignore it:

limit(RootOf(_Z^3+a*_Z+2, index = real[1]), a = -infinity);
                               0

In fact the root grows as sqrt at -infinity.

Hello,

When starting Maple, i get an error message like:

All Drivers are up to date, Im running a system Win10-64Bit on a notebook.

Has anybody had the same problem?

Thanks in Advance

hi every one,i want to create some kind of numbering for index, how can i generate them using "seq" command or "for loop" ?
 

Download problem.mw

solve(z^(1+I) = 1, z, allsolutions = true);
                      exp((1 + I) Pi _Z1)
getassumptions(_Z1);
                         {_Z1::integer}

Since this is a single-valued power function, there is only a finite number of solutions. evalc correctly gives exp(-2*Pi) for _Z1=-1.

evalf doesn't help here regardless of the level of precision, I think because it always generates a non-zero imaginary part for exp(-(1+I)*Pi):

seq(print(evalf(evalf[d]((exp((-1-I)*Pi))^(1+I)))), d = 10 .. 3010, 300);
                                             -12  
              0.001867442732 - 1.361179007 10    I
                                            -312  
             0.001867442732 - 1.674479874 10     I
                                           -610  
               1.000000000 + 2.386571217 10     I
                                           -910  
               1.000000000 + 8.502509375 10     I
                                            -1212  
             0.001867442732 - 1.646483173 10      I
                                            -1514  
             0.001867442732 - 4.556560265 10      I
                                            -1812  
             0.001867442732 - 1.287611101 10      I
                                            -2112  
             0.001867442732 - 1.072784224 10      I
                                          -2410  
              1.000000000 + 8.162729354 10      I
                                            -2713  
             0.001867442732 - 7.375390371 10      I
                                          -3010  
              1.000000000 + 1.988371005 10      I

Unrelated, but it would be nice to have a simple way to display lists/matrices with specified width and alignment.

In my code I'm trying to catch the case when a certain limit doesn't exist:

limit(exp(-I*a*z)/a, a = infinity) assuming Im(z) > 0;
                               0

Doesn't work. Strangely, this works:

limit(exp(-I*a*z)/a, a = infinity) assuming Im(z) > 0, z::complex;
                           undefined

But this again doesn't:

limit(cos(a*z)/a, a = infinity) assuming Im(z) > 0, z::complex;
                               0

(because the limit of cos(a*z) returns -1..1).

So then I decide to check the exponents directly:

is(a*Im(z) > 0) assuming a > 0, Im(z) > 0;
                             false

Doesn't work, even though it works for arbitrary f:

is(a*f(z) > 0) assuming a > 0, f(z) > 0;
                              true

I found a construct that works:

signum(Im(a*z)) assuming a > 0, Im(z) > 0;
                               1

Would it be possible to improve the handling of the assumptions on Re/Im though?