Hello my dear friends ...
I wrote a FORTRAN code for simulating a transient 2D laminar flow in fintite differences method.
I have 2 problems with my code. One of them is with PARDISO and the other is with DSS.
for PARDISO :
My code solves 3 systems of linear equations respectively in each iteration :
The matrices of the coefficients for the first system and the second one are the same. The systems' difference is just the RHS.
The matrices of the coefficients for the third system is different. but the it's dimension is the same.
I used 2 approaches (i.e. 2 SOLVERs in one code in eatch iteration to campare the results of the same system of equations between them):
In the first part of each iteration, I make the matrix of coefficients of each of the 3 systems of equations "by myself" (for example A , B , C) and then I send the system to DGESV to solve. Fortunately it gives me the best results.
In the second part of each iteration, I send the the matrix of coefficients (A , B , C) to the DDNSCSR to make it in CSR form.Then I send it to the PARDISO and it gives me almost the same results as which DGESV had returnet to me.
MY PROBLEM IS : when I make the CSR format by myself and send it to the PARDISO, the results are not the same !!!
I should note that the CSR format which I made is EXACTLY ( !!! ) the same as the CSR format which was made by DDNSCSR ( !!! )
I mean exactly : the inlet CSR format matrices which was sent to PARIDISO, are exactly the same in 2 approach. (I had checked it completely with a separate code which I had writtenbefore)
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for DSS : I don't know anything about the applying the DSS solver. I will send my code (it is the same code but I substitude PARDISO with DSS). I don't know why it didn't work at all. ( I gave the solver from internet)
Thank for your help.