Hello thereI tried solving Ax = b with A being a symmetric matrix of size N =5,26,338; with number of nonzeros being 20,787,787.The matrix is represented in CSR format. Thus the memory reqd to represent the linear system being: Memory(Values) = 158.6 MB Memory(Columns) = 79.3 MB Memory(rowindex) = 2.0 MB Memory(RHS) = 2.0 MB Total Memory = 241.91 MBI used the following options in creating the dss handle:MKL_INT opt = MKL_DSS_DEFAULTS; MKL_INT sym = MKL_DSS_SYMMETRIC; MKL_INT type = MKL_DSS_INDEFINITE; MKL_INT opt_parallel = MKL_DSS_METIS_OPENMP_ORDER;To my surprise, I found that the memory consumption (using Windows Task Manager + VS2010 Debugger) for the following two steps were out of proportion:1. Rerorder step(dss_reorder)required 0.63 GB of memory2. Factorization(dss_factor_real)requird 4.38 GB of memoryOn calling dss_delete, I recovered 6.39 GB. So, it is quite clear that reordering and factorization takes all the memory.I am not sure why this much of memory is being used up considering the fact that the matrix that is being factored is only about 240 MB.However, as far as I understand, the LU factorization should not require more than 2*240 = 480 MB (for this problem). Am I right?Although, am able to solve the system in a machine with 8 GB RAM, the solver fails in a 32 bit machine with 4 GB RAM. So, how do we make the solver work on low-end machines?Looking forward for your response at the earliest,Thanks & RegardsVaidy
Para obtener más información sobre las optimizaciones del compilador, consulte el aviso sobre la optimización.