I want to  return {x = 0., y = 1.158748796 + 0. I}  as  {x = 0., y = 1.158748796 }.  The solution is coming from:

soln3:= fsolve({b1, b2}, {x = 0 .. infinity, y = 0 .. infinity}); 

and the second solution is coming from:
 soln4:= fsolve({b1, b2}, {x = -infinity ..0, y = -infinity .. 0}); 

See my code below

restart:

Procedure

doCalc:= proc( xi )

                 # Import Packages
                 uses ArrayTools, Student:-Calculus1, LinearAlgebra,
                      ListTools, RootFinding, plots, ListTools:
                 local gamma__1:= .1093,
                       alpha__3:= -0.1104e-2,
                       k__1:= 6*10^(-12),
                       d:= 0.2e-3,
                       theta0:= 0.0001,
                       eta__1:= 0.240e-1,
                       alpha:= 1-alpha__3^2/(gamma__1*eta__1), 
                       c:= alpha__3*xi*alpha/(eta__1*(4*k__1*q^2/d^2-alpha__3*xi/eta__1)),
                       theta_init:= theta0*sin(Pi*z/d),
                       n:= 30,
                       g, f, b1, b2, qstar, OddAsymptotes, ModifiedOddAsym,
                       qstarTemporary, indexOfqstar2, qstar2, AreThereComplexRoots,
                       soln1, soln2, qcomplex1, qcomplex2, gg, qq, m, pp, j, i,
                       AllAsymptotes, p, Efun, b, aa, F, A, B, Ainv, r, theta_sol, v, Vfun, v_sol,minp,nstar,
                       soln3, soln4, Imagroot1, Imagroot2;

# Assign g for q and plot g, Set q as a complex and Compute the Special Asymptotes

  g:= q-(1-alpha)*tan(q)+ c*tan(q):
  f:= subs(q = x+I*y, g):
  b1:= evalc(Re(f)) = 0: 
  b2:= y-(1-alpha)*tanh(y) -(alpha__3*xi*alpha/(eta__1*(4*k__1*y^2/d^2+alpha__3*xi/eta__1)))*tanh(y) = 0:
  qstar:= (fsolve(1/c = 0, q = 0 .. infinity)):
  OddAsymptotes:= Vector[row]([seq(evalf(1/2*(2*j + 1)*Pi), j = 0 .. n)]);

# Compute Odd asymptote

  ModifiedOddAsym:= abs(`-`~(OddAsymptotes, qstar));
  qstarTemporary:= min(ModifiedOddAsym);
  indexOfqstar2:= SearchAll(qstarTemporary, ModifiedOddAsym);
  qstar2:= OddAsymptotes(indexOfqstar2);

# Compute complex roots

  AreThereComplexRoots:= type(true, 'truefalse');
  try
   soln1:= fsolve({b1, b2}, {x = min(qstar2, qstar) .. max(qstar2, qstar), y = 0 .. infinity}); 
   soln2:= fsolve({b1, b2}, {x = min(qstar2, qstar) .. max(qstar2, qstar), y = -infinity .. 0}); 
   qcomplex1:= subs(soln1, x+I*y); 
   qcomplex2:= subs(soln2, x+I*y);
   catch:
   AreThereComplexRoots:= type(FAIL, 'truefalse');
  end try;

# Compute the rest of the Roots
  soln3:= fsolve({b1, b2}, {x = 0 .. infinity, y = 0 .. 10}); 
  soln4:= fsolve({b1, b2}, {x = -infinity ..0, y = -infinity .. 0}); 
  Imagroot1:=subs(soln3, I*y); 
  Imagroot2:= subs(soln4, I*y); 
  OddAsymptotes:= Vector[row]([seq(evalf((1/2)*(2*j+1)*Pi), j = 0 .. n)]); 
  AllAsymptotes:= sort(Vector[row]([OddAsymptotes, qstar])); 

  if AreThereComplexRoots
  then gg:= [qcomplex1, qcomplex2,op(Roots(g, q = 0.1e-3 .. AllAsymptotes[1])),
              seq(op(Roots(g, q = AllAsymptotes[i] .. AllAsymptotes[i+1])), i = 1 .. n)];
  elif not AreThereComplexRoots 
  then gg:= [op(Roots(g, q = 0.1e-3 .. AllAsymptotes[1])), seq(op(Roots(g, q = AllAsymptotes[i] .. AllAsymptotes[i+1])), i = 1 .. n)];
  end if:

# Remove the repeated roots if any & Redefine n

  qq:= MakeUnique(gg):
  m:= numelems(qq):

## Return all the plots
            return qq, Imagroot1,Imagroot2, p, soln3, soln4;
  end proc:

ans:=[doCalc(0.06)]:
ans[5];
                {x = 0., y = 1.158748796 + 0. I}
ans[6];
                   {x = 0., y = -1.158748796}
 

I'm using a procedure but the out is not returned. Please why?

restart:

Procedure

doCalc:= proc( xi )

                 # Import Packages
                 uses ArrayTools, Student:-Calculus1, LinearAlgebra,
                      ListTools, RootFinding, plots, ListTools:
                 local gamma__1:= .1093,
                       alpha__3:= -0.1104e-2,
                       k__1:= 6*10^(-12),
                       d:= 0.2e-3,
                       theta0:= 0.0001,
                       eta__1:= 0.240e-1,
                       alpha:= 1-alpha__3^2/(gamma__1*eta__1), 
                       c:= alpha__3*xi*alpha/(eta__1*(4*k__1*q^2/d^2-alpha__3*xi/eta__1)),
                       theta_init:= theta0*sin(Pi*z/d),
                       n:= 30,
                       g, f, b1, b2, qstar, OddAsymptotes, ModifiedOddAsym,
                       qstarTemporary, indexOfqstar2, qstar2, AreThereComplexRoots,
                       soln1, soln2, qcomplex1, qcomplex2, gg, qq, m, pp, j, i,
                       AllAsymptotes, w, Efun, b, aa, F, A, B, Ainv, r, theta_sol, v, Vfun, v_sol,minp,nstar,
                       soln3, soln4, Imagroot1, Imagroot2;

# Assign g for q and plot g, Set q as a complex and Compute the Special Asymptotes

                       qq := [2.106333379+.6286420119*I, 2.106333379-.6286420119*I, 4.654463885, 7.843624703, 10.99193295,14.13546782, 17.27782732, 20.41978346, 23.56157073, 26.70327712, 29.84494078, 32.98658013,         36.12820481, 39.26982019, 42.41142944, 45.55303453, 48.69463669, 51.83623675, 54.97783528,                     58.11943264, 61.26102914, 64.40262495, 67.54422024, 70.68581510, 73.82740963,                                 76.96900389, 80.11059792, 83.25219177, 86.39378546, 89.53537903, 92.67697249];
                        m:= numelems(qq):

                        for i from 1 to m do 
                        w[i] := gamma__1*alpha/(4*k__1*qq[i]^2/d^2-alpha__3*xi/eta__1);
                        end do;

## Return all the plots
  return w;
  end proc:

ans:=[doCalc(0.06)]:
ans[1];
                              
 

Hi, please how do I return the roots of a function in the form of I*y. The roots are [-.2381948477, -0.1434221912e-3, 0., 0.1434221912e-3, .2381948477] and I want to return them as [-.2381948477*I, -0.1434221912e-3*I, 0., 0.1434221912e-3*I, .2381948477*I]. I tried to use subs () function but couldn't work.

with(Student[Calculus1]):

soln := Roots(y-0.4646295e-3*tanh(y)+0.1839145082e-2*tanh(y)/(0.6000000000e-3*y^2-0.1840000000e-2), y);

subs(soln, I*y);

Is it possible to solve the mixed PDEs below using the method of lines or any other numerical scheme?

B.C:

theta(0,t) = theta(d,t) = 0

v(0,t) = v(d,t) = 0

I.C: theta(z,0) = \thetab*sin(pi/2)*z,  v(z,0) =0 at t =0  for both the initial conditions, where thetab = 0.0001 

% parameters.

K3 = 7.5*10^(-12);

eta2 = 0.1361;

alpha2 = -0.1104;

gamma1 = 0.1093;

d = 0.0002;

xi = 0.1; 

Note: xi is the controlling parameter. For instance, we can plot theta and v for different values of xi.

I tried matlab but no standard scheme to solve the problem because of the partial^2 theta/partial d partial t term. It would have been possible to use pdepe in Matlab if not for the mixed derivative. Please any help.

Thank you

Hi,

Please can someone help me with a sample code for bifurcation? You can use parameter values for the parameters. I'm using maple 18. Below is my model:

Download Bifurcation.mw