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## Re: [Octave forge] [bim package]

**From**: |
c. |

**Subject**: |
Re: [Octave forge] [bim package] |

**Date**: |
Sun, 4 Feb 2018 17:58:35 +0100 |

>* On 4 Feb 2018, at 17:55, c. <address@hidden> wrote:*
>* *
>* This code snippet for example:*
>* *
>*>> pkg load bim*
>*>> x = [linspace(0, .5, 100), linspace(.5, 1, 200)(2:end)].';*
>*>> A = bim1a_laplacian (x, 1, 1);*
>*>> b = bim1a_rhs (x, 1, 1);*
>*>> u = zeros (size (x));*
>*>> u(2:end-1) = A(2:end-1, 2:end-1) \ b(2:end-1);*
>*>> plot (x, u, 'x-')*
>* *
>* solves *
>* *
>* - u''(x) = 1 in 0 < x < 1*
>* u(0) = u(1) = 0*
>* *
>* on a piece-wise uniform mesh.*
And, to try a more complex non-uniform mesh spacing, you could test this:
>*> y = x .^ 3;*
>*> A = bim1a_laplacian (y, 1, 1);*
>*> b = bim1a_rhs (y, 1, 1);*
>*> u = zeros (size (y));*
>*> u(2:end-1) = A(2:end-1, 2:end-1) \ b(2:end-1);*
>*> plot (y, u, 'x-')*
c.