# Interface with SuperLU¶

It is possible to call SuperLU 3.0 (https://portal.nersc.gov/project/sparse/superlu/superlu_3.0.tar.gz) from *Gmm++*. The following function defined in the file `gmm/gmm_superlu_interface.h`

is available:

```
SuperLU_solve(A, X, B, condest, permc_spec = 1)
```

solves the system `AX = B`

where A is a sparse matrix of base type `float, double, std::complex<float>, or std::complex<double>`

. `permc_spec`

should be 0, 1 or 2 for respectively use the natural ordering, use minimum degree ordering on structure of `A'A`

or use minimum degree ordering on structure of `A'+A`

(1 is the default value), `condest`

should be a reference on a double, it returns an estimate of the condition number of the matrix `A`

.

To use these functions, you need to install SuperLU and compile your code with the additional options:

```
g++ ... -DGMM_USES_SUPERLU (dir_of_superlu)/superlu.a -lblas -I(dir_of_superlu)
```

Some other functionalities of SuperLU can be interfaced.