Well, should it also work when b is a one column matrix ? Im am a complete newbie (coming from the Scilab world...) so I forgot this subtle difference in Julia...
S. Le lundi 15 septembre 2014 18:49:02 UTC+2, Andreas Noack a écrit : > > Okay. I can see the problem now. The reason is that you have defined b as > a matrix and I had it defined as a vector. It works if you define b = > rand(1000), but the stack overflow is a bug. I'll look into it. > > Med venlig hilsen > > Andreas Noack > > 2014-09-15 12:12 GMT-04:00 Stéphane Mottelet <stephane...@gmail.com > <javascript:>>: > >> Hello, >> >> I use Julia-0.3.0 (OSX version). Here is a testcase : >> >> a=sprand(1000,1000,0.1); >> af=factorize(a); >> b=rand(1000,1); >> x=(af')\b; >> >> ERROR: stack overflow >> in Ac_ldiv_B! at linalg/umfpack.jl:354 (repeats 80000 times) >> >> S. >> >> >> Le lundi 15 septembre 2014 18:01:46 UTC+2, Viral Shah a écrit : >> >>> Which version of Julia are you using? >>> >>> Please do provide a test case to generate Af and b, so that I can try >>> reproduce it. >>> >>> -viral >>> >>> On Monday, September 15, 2014 2:00:11 PM UTC+5:30, Stéphane Mottelet >>> wrote: >>>> >>>> Hello, >>>> >>>> It seems that it does not work as you said : >>>> >>>> *julia> (A**f)'\b* >>>> >>>> *ERROR: stack overflow* >>>> >>>> * in Ac_ldiv_B! at linalg/umfpack.jl:354 (repeats 80000 times)* >>>> >>>> In order to motivate my needs, I have to solve both systems, one with A >>>> and the other one with transpose(A). >>>> >>>> >>>> S. >>>> >>>> >>>> >>>> Le vendredi 12 septembre 2014 17:43:50 UTC+2, Andreas Noack a écrit : >>>>> >>>>> I believe that if Af = lufact(A) for sparse A then Af\b will give you >>>>> what you want. The expression is parsed such that the transpose is not >>>>> actually computed. Instead it calls the methods Ac_ldiv_B which calls the >>>>> right solver in UMFPack. >>>>> >>>>> Med venlig hilsen >>>>> >>>>> Andreas Noack >>>>> >>>>> 2014-09-12 9:55 GMT-04:00 Stéphane Mottelet <stephane...@free.fr>: >>>>> >>>>>> >>>>>> Hello, >>>>>> >>>>>> How do you solve transpose(A)*x=b (without refactoring) when A is >>>>>> sparse and has been factored ? UMFPack allows this in other >>>>>> implementations >>>>>> (e.g. Scilab). >>>>>> >>>>>> Thanks for help >>>>>> >>>>>> S. >>>>>> >>>>> >>>>> >
