PHPC - CONJUGATE GRADIENT PROJECT

HOWTO COMPILE AND RUN
=====================

Requirements : 

- a recent compiler (like gcc or intel)
- a BLAS library (like openblas or intel MKL)

compile on SCITAS clusters :

```
$ module load gcc openblas
$ git clone ssh://git@c4science.ch/source/CG-PHPC.git
$ make
```

run on a SCITAS cluster interactively (reservation name is indicative) :

```
$ salloc -N 1 -n 1 --reservation=phpc-reservation
$ srun ./conjugategradient lap2D_5pt_n100.mtx
```
You should see this output (timing is indicative) :

```
$ srun ./conjugategradient lap2D_5pt_n100.mtx 
size of matrix = 10000 x 10000
Call cgsolver() on matrix size (10000 x 10000)
	[STEP 488] residual = 1.103472E-10
Time for CG = 36.269389 [s]
```

The given example is a 5-points stencil for the 2D Laplace problem. The matrix is in sparse format.

The matrix format is [Matrix Market format (.mtx extension)](https://sparse.tamu.edu/). You can use other matrices there or create your own.