Recent content by omer21

  1. O

    Nested Summation Computation for M_K with MATLAB

    M_{K}=\frac{1}{2^{k+1}-2}\sum_{i=0}^{L-1}\sum_{l=1}^{K}\binom{K}{l}h_{i}i^{l}M_{K-l} M_0=1 and the size of h_i is L. I tried to compute this summation in matlab, my attempt is as following: clear h=[ (1+sqrt(3))/4 (3+sqrt(3))/4 (3-sqrt(3))/4 (1-sqrt(3))/4]'; % for simplicity i take...
  2. O

    Backward euler method for heat equation with neumann b.c.

    Your plots are correct. Thank you for your effort.
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    Backward euler method for heat equation with neumann b.c.

    Actually my codes are working accurately when B.C.s are dirichlet, but when B.C.s are turned to Neumann i confused how to edit the codes anyway i will look your codes. Thank you jfgobin for your help.
  4. O

    Backward euler method for heat equation with neumann b.c.

    You are right about T=T(:,1);. It ought to be T=T(:,end);. I want to show what i did so i multiplied by 0 because of u'_x(0,t)=0. I put T(m+1,j)=2; just after second for loop but still i can't get correct results.
  5. O

    Backward euler method for heat equation with neumann b.c.

    Initial vector is right. You miss subscript at b. c. i guess. B.C's are specified at the derivative of u.
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    Backward euler method for heat equation with neumann b.c.

    I am trying to solve the following pde numerically using backward f.d. for time and central di fference approximation for x, in MATLAB but i can't get correct results. \frac{\partial u}{\partial t}=\alpha\frac{\partial^{2}u}{\partial x^{2}},\qquad u(x,0)=f(x),\qquad u_{x}(0,t)=0,\qquad...
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    Computing Integrals with Wavelet Scaling and Translation Parameters

    I am looking for a software that can compute the following integral ∫_0^1f(x)\phi(2^jx-k)dx. \phi(x) is scaling function of a wavelet family (especially Daubechies), j and k are scaling and translation parameters respectively.
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    Wavelet Theory: Solving ∫t^pψ(t)dt=0

    I substituted \psi(t)=[∑_k(−1)^kc_k\phi(2t+k−N+1)] into ∫t\psi(t)dt. Then i got ∫t[∑_k(−1)^kc_k\phi(2t+k−N+1)]dt=∑_k(−1)^kc_k∫t\phi(2t+k−N+1)]dt=0. Actually i am not sure how to find the above integral but i did some change of variables and used integration by parts...
  9. O

    Wavelet Theory: Solving ∫t^pψ(t)dt=0

    i can see 5.14 but i can not obtain 5.15 and 5.16. Actually i get \sum_k (-1)^kc_k.0=0 instead of \sum_k (-1)^k k^p c_k=0 from the integral ∫t^p [\sum_k (-1)^kc_k \phi(2t+k-N+1)]dt=0.
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    Wavelet Theory: Solving ∫t^pψ(t)dt=0

    I don't understand how to get the equation \sum_k (-1)^kk^pc_k=0 from ∫t^pψ(t)dt=0 from here on page 80. Can somebody explain it?
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    How do we get this equality about bilinear form

    Yes, it is. @Ray vickson Could you explain in more details?
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    How do we get this equality about bilinear form

    Homework Statement B(u,u)=\int_{0}^{L}a\frac{du}{dx}\frac{du}{dx}dx B(.,.) is bilinear and symmetric, δ is variational operator. In the following expression, where does \frac{1}{2} come from? As i know variational operator is commutative why do not we just pull δ to the left? B(\delta...
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    How to determine natural boundary condition and essential b.c. in Ritz method

    I am trying to understand Ritz method, but i have troubles wtih determining the boundary conditions. After weak formulation of a differential equation how do we determine natural and essential b.c.? What are boundary terms, secondary variables, primary variables, natural and essential...
  14. O

    Help with initial value problem(IVP)

    Discriminant is not -30, it is 6^2-4.1.9=0
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