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rahul May 30, 2002 13:49

ILU Factorisation
hello everybody i want to solve a 2d square grid u''(x)+u''(y)=f(x,y) using ILU ( incomplete lower upper )factorisation. Please anyone help with a related text or solution. Thanks in advance rahul

Paul May 30, 2002 22:21

Re: ILU Factorisation
You may refer to Numerical Recipes (C/Fortran) at or

Anthony Wachs May 31, 2002 04:54

Re: ILU Factorisation
Just a simple question : why incomplete factorization ? Why don't you consider all the terms in your factorization and calculate the complete LU ?

Moreover the laplacian operator involved in your equation is symmetric, thus you may use the LLt factorization (Cholevski) which is faster (half the time) since you only have to perform the L matrix calculation instead of L and U

As Paul mentioned, you are likely to find all the algorithms you need on

Hope it could help, Anthony

mukkarum June 5, 2002 23:32

Re: ILU Factorisation
Sir i am working on research project "revemping of Francis Turbine applying CFD". I have got book "An introduction to computational fluid dynamics (finite volume) by malalasakra" it is very good book and i have understand SIMPLE, SIMPLER AND SIMPLEC method of solving Navier Stock equation but in this book just presentation that how Navier Stock equation can be solved but there is no solve example. Do you know any book or article in which this type of example is present. I mean that for any given problem(good if turbine rotor)firstly assume pressure field and then find velocity field then check pressure correction equation and repeat this procedure still convergence occure. waiting for your prompt reply thanks

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