## Search found 90 matches

- Mon Feb 22, 2016 4:43 pm
- Forum: User discussion
- Topic: Magma Sparse Example
- Replies:
**1** - Views:
**3872**

### Re: Magma Sparse Example

Dear Costa, I can not exactly reproduce your problem, but have some comments. You use opts.solver_par without initializing most of the fields. E.g. you should set: opts.solver_par.maxiter = 1000; opts.solver_par.rtol = 1e-10; opts.solver_par.rtol = 1e-10; opts.solver_par.restart = 50; An elegant wor...

- Sun Oct 18, 2015 9:06 am
- Forum: User discussion
- Topic: LOBPCG method for Eigen Value Computation.
- Replies:
**4** - Views:
**1956**

### Re: LOBPCG method for Eigen Value Computation.

Dear Nithish, for a plain LOBPCG, use ./testing_dsolver --solver 8 --ev k /path/to/the/matrix If you want to use a preconditioner (faster solver convergence in many cases) type ./testing_dsolver --solver 8 --ev k --precond x /path/to/the/matrix where x = 1 is Jacobi, x = 2 is ILU. Let me know whethe...

- Tue Sep 15, 2015 7:30 am
- Forum: User discussion
- Topic: Solving with multiple RHS
- Replies:
**8** - Views:
**3307**

### Re: Solving with multiple RHS

Maybe you can write out one sample matrix, such that I can try to figure out what is happening? If yes, just pass me the URL.

Thanks, Hartwig

Thanks, Hartwig

- Tue Sep 15, 2015 4:52 am
- Forum: User discussion
- Topic: Solving with multiple RHS
- Replies:
**8** - Views:
**3307**

### Re: Solving with multiple RHS

Badlishah,

this error typically occurs if the linear system is not positive definite, which is needed for using CG. In particular, the system needs to be positive ( A=A' ) and all eigenvalues of the system need to be positive. Is this true for your system? What is the origin?

Thanks, Hartwig

this error typically occurs if the linear system is not positive definite, which is needed for using CG. In particular, the system needs to be positive ( A=A' ) and all eigenvalues of the system need to be positive. Is this true for your system? What is the origin?

Thanks, Hartwig

- Mon Sep 14, 2015 11:58 pm
- Forum: User discussion
- Topic: Solving with multiple RHS
- Replies:
**8** - Views:
**3307**

### Re: Solving with multiple RHS

Badlishah,

indeed, not all solvers support block-RHS at this point. Please try with preconditioned Conjugate Gradient (called zbpcg).

Thanks, Hartwig

indeed, not all solvers support block-RHS at this point. Please try with preconditioned Conjugate Gradient (called zbpcg).

Thanks, Hartwig

- Sun Sep 06, 2015 12:59 am
- Forum: User discussion
- Topic: Solving with multiple RHS
- Replies:
**8** - Views:
**3307**

### Re: Solving with multiple RHS

Badlishah, at the current state, I would suggest to transform the sparse RHS-matrix into a dense matrix, such that you have a block of vectors (dense matrix) RHS. magma_zmconvert( B, &B2, Magma_CSR, Magma_DENSE, queue ); Then, you use an initial guess for the block solution (X) also as dense matrix....

- Tue Sep 01, 2015 11:26 am
- Forum: User discussion
- Topic: CSC To CSR Matrix Conversion
- Replies:
**5** - Views:
**2309**

### Re: CSC To CSR Matrix Conversion

Badlishah, There is no function for this at this point (all MAGMA sparse is using 0-based indexing). At this point, I would do this manually on the CPU: for( magma_int_t i=0; i<A.num_rows+1; i++) { A.row += 1; } for( magma_int_t i=0; i<A.nnz; i++) { A.col += 1; } Please let me know if you have probl...

- Fri Aug 14, 2015 9:02 am
- Forum: User discussion
- Topic: Help please to get CUDA 6.5 working on Ubuntu 12.04
- Replies:
**3** - Views:
**1303**

### Re: Help please to get CUDA 6.5 working on Ubuntu 12.04

John,

did you consider updating your ubuntu version? this might be the easier way to go.

Hartwig

did you consider updating your ubuntu version? this might be the easier way to go.

Hartwig

- Mon Aug 03, 2015 10:21 am
- Forum: User discussion
- Topic: Magma version of BLAS routine ZSBMV
- Replies:
**4** - Views:
**903**

### Re: Magma version of BLAS routine ZSBMV

John,

now I see what you want: element-wise multiplication of a vector. And you found a workaround using a sparse matrix. I promise, once you have the code running on the GPU using MAGMA, I'll write a function doing this quickly. This is very easy on a GPU.

Hartwig

now I see what you want: element-wise multiplication of a vector. And you found a workaround using a sparse matrix. I promise, once you have the code running on the GPU using MAGMA, I'll write a function doing this quickly. This is very easy on a GPU.

Hartwig

- Mon Aug 03, 2015 8:25 am
- Forum: User discussion
- Topic: Magma version of BLAS routine ZSBMV
- Replies:
**4** - Views:
**903**

### Re: Magma version of BLAS routine ZSBMV

John, if I do understand you correct, you want to multiply a sparse matrix with a vector - is this correct? And the sparse matrix has a nice diagonal property? If so, I would recommend just using a default sparse matrix vector (SpMV) routine. These are typically highly optimized, and will sure satis...