Some of the Rotation Coefficients are not calculating properly.

Question_about_Ricci_Rotation_Coefficients.mw

Tried posting responses to a question this evening. Click the question title, hit the "reply" button and enter a phrase like "Clarification" in the Title filed of the reply form, the reply form just disappears. Tried this in Firefox and Chrome - same behaviour. Means I can no longer contribute - has somebody broken something??? Or I have a problem with *all* my browsers

PS not even sure that this post will appear correctly

I have data file with 6 columns:

X Y Z B1 B2 B3

i.e. 3 coordinates (with some step) and values of B-functions at that 3D point. How to make interpolation of these B-functions to have them in arbitrary (x,y,z) point?

Then I need to solve diff equations like this:

x''(s)+f(...)=0

f(...) depends on x,y,z,x',y',z' and B1,B2,B3. How to write this dsolve(...) construction when we have interpolations inside?

Thanks.

I am trying to understand how maple "isprime" algorithm works. But I can't find anywhere what special_primes means.

 showstat(isprime);

isprime := proc(n)
local btor, nr, p, r;
   1   if not type(n,'integer') then
   2     if type(n,('complex')('numeric')) then
   3       error "argument must be an integer"
         else
   4       return 'isprime(n)'
         end if
       end if;
   5   if n < 2 then
   6     return false
       elif member(n,isprime:-special_primes) then
   7     return true
       elif igcd(2305567963945518424753102147331756070,n) <> 1 then
   8     return false
       elif n < 10201 then
   9     return true
       elif igcd(8496969489233418110532339909187349965926062586648932736611545426342203893270769390909069477309509137509786917118668028861499333825097682386722983737962963066757674131126736578936440788157186969893730633113066478620448624949257324022627395437363639038752608166758661255956834630697220447512298848222228550062683786342519960225996301315945644470064720696621750477244528915927867113,n) <> 1 then
  10     return false
       elif n < 1018081 then
  11     return true
       else
  12     r := gmp_isprime(n);
  13     if not r or n <= 5000000000 then
  14       return r
         end if;
  15     nr := igcd(408410100000,n-1);
  16     nr := igcd(nr^5,n-1);
  17     r := iquo(n-1,nr);
  18     btor := modp(('power')(2,r),n);
  19     if cyclotest(n,btor,2,r) = false or irem(nr,3) = 0 and cyclotest(n,btor,3,r) = false or irem(nr,5) = 0 and cyclotest(n,btor,5,r) = false or irem(nr,7) = 0 and cyclotest(n,btor,7,r) = false then
  20       return false
         end if;
  21     if isqrt(n)^2 = n then
  22       return false
         end if;
  23     for p from 3 while numtheory:-jacobi(p^2-4,n) <> -1 do
  24       NULL
         end do;
  25     return evalb(TraceModQF(p,n+1,n) = [2, p])
       end if
end proc

I have a big file (~30Mb) with a single algebraic expression (file contains only one string of the form `expr := a*b + ... :` ). I would like to import this expression into Maple and I use `read` function for that:

    read "s.maple":

I wait for 2 hours, but Maple does not response and no any output provided. Is there any special function for import such data?

I use console Maple18 Linux x86 64.

Update. All goes fine in Maple 16, so the issue is relevant for Maple17 and Maple18.

Can somebody help me on this problem?

Download erni_stability_try.mw

PLEASE HELP ME. I NEED HELP REALLY BAD.

Restrict calculation to real numbers.

Using y' = u, express the oscillator equation: y" + 3y' + 2y = cos(t) as a first order system. 

Plot an approximate solution curve for the specified initial conditions.

[x₀=5, y₀=1],[x₀=-2, y₀=-4],[x₀=0, y₀=.1],

This is what i have so far but i am not sure if its correct.

Eulers modified method: 

with(RealDomain);

x[0] := 0;

y[0] := 5;

t[0]=0

h := .1;

for n to 100 do

x[n] := x[n-1]+h*(x[n-1]+y[n-1]);

k1 := x[n-1]+y[n-1];

k2 := h*k1+x[n]+y[n-1];

k := 1/2*(k1+k2);

y[n] := h*k+y[n-1]

end do;

data := [seq([x[n], y[n]], n = 0 .. 100)];
G1 := plot(data, style = point, color = "blue");
G1;

Hi,

I want to write a proc to calculate exponential averages. Each call will add one data point to the averge. To do that, I need to store the previous average. I can do that by handing the previous average back to the proc at the next call, but I'd rather store it in the proc. Is there a way to guarantee that a variable---once set---remains alive keeping the last value upon entering the proc again? Note that I need the variable to be local to each instance of the proc since I will have several of these running in parallel (I intend to create these procs using the module factory scheme outlined in the programming guide). So I cannot store the previous average in a global variable since that would not be unique to a given instance.

Any ideas out there?

TIA,

Mac Dude

1. Work with the function 

f(x) = 5x^2-125/x^2-16

1. Find the horizontal asymptotes
2. Draw the graph of the function.  Show all horizontal and vertical asymptotes on your graph.  Edit the domain and the range to get a “good window” that clearly shows the shape of the function and all the important features, such as zeros, intercepts, maxima and minima, horizontal and vertical asymptotes. 

 when i  input  bellow

• Maple can output

i want to find the stability of this equation, but there is seem to have some problems..can somebody help me..

y := A*(1/x+x*exp(-2*sqrt(-1)*b))+4*(exp(h)-1)^2*(2*exp(-sqrt(-1)*b)-3*(exp(h)-1)^2*x^(-exp(h)+1)*exp(sqrt(-1)*b*(-exp(h)+1-1))+3*x^(-exp(h)+1)*exp(sqrt(-1)*b*(-exp(h)+1-1)))/(3*(1-r))-exp(-2*sqrt(-1)*b)/x-x;

subs(A = (1+r)/(1-r), %);

subs(r = (1/3)*(exp(h)-1)^2, %);

subs(b = m*Pi*(exp(h)-1), %);

subs(m = 1, %);

subs(h = 0.5e-1, %);

> ans := solve(%, x);
Warning, solutions may have been lost
ans:=

> r1 := ans[1];
Error, invalid subscript selector
> r2 := ans[2];
Error, invalid subscript selector

Any suggestions (or perhaps related examples?) illustrating how I might numerically solve for f(t) in the following non-linear integral equation?  In Fortran, I would start with a guess f(t)=T0, and then search in the neighborhood for a minimum (in the error), but I am not familiar with numerical searches and methods in Maple.  Thank you for any suggestions or leads.

(a,b,... etc are all real)

Download Integraleqn.mw

Hello, I am newbie in Maple...

I tried to make a simple iteration, and I would like to get complex results for Z2, Z4 and Z5, as they have complex tag in them.

Would anybody to be so kind, to have a look at my file, and tell me, what's the mistake?
zernike_BB.mw

Thank you:

Attila

How can I call to an external batch file (which is located in a given directory) from a Maple session?

Thanks,

Janos Pinter

Hi all,

I would like to know how could I plot an ODE for 3 values of a parameter in the same figure.

sol:=dsolve(dsys,numeric,parameters=[t]);

p:=proc(t)sol(parameters=[t]); plots:-odeplot(sol,[x,f(x)],-1..0,_rest) end proc;

p(-1); p(-0.5); p(-0.1);

Here, I have 3 figures one for each value. I used with(plots): display(p(-1); p(-0.5); p(-0.1)). But doesn't work.

Thanks for your help.