The LDPC coder and decoder are implemented in a shared library, dynamically loaded at run-time using the [oai shared library loader](file://../../../../common/utils/DOC/loader.md). The code loading the LDPC library is in [nrLDPC_load.c](file://../nrLDPC_load.c), in function `load_nrLDPClib`, which must be called at init time.
## Selecting the LDPC library at run time
By default the function `int load_nrLDPClib(void)` looks for `libldpc.so`, this default behavior can be changed using the oai loader configuration options in the configuration file or from the command line as shown below:
>loading `libldpc_optim8seg.so` instead of `libldpc.so`
#### Examples of ldpc shared lib selection when running nr softmodem's:
loading `libldpc_optim8seg.so` instead of `libldpc.so`:
@@ -18,9 +20,160 @@ By default the function `int load_nrLDPClib(void)` looks for `libldpc.so`, this
........................
```
Today, this mechanism is not available in the `ldpctest` phy simulator which doesn't initialize the [configuration module](file://../../../../common/config/DOC/config.md). loads `libldpc.so` and `libldpc_orig.so` to compare the performance of the two implementations.
A mechanism to select ldpc implementation is also available in the `ldpctest` phy simulator via the `-v`option, which can be used to specify the version of the ldpc shared library to be used.
#### Examples of ldpc shared lib selection when running ldpctest:
Loading libldpc_cuda.so, the cuda implementation of the ldpc decoder:
```$ ./ldpctest -v _cuda
Initializing random number generator, seed 0
block length 8448:
n_trials 1:
SNR0 -2.000000:
[CONFIG] get parameters from cmdline , debug flags: 0x00400000
[CONFIG] log_config: 2/3 parameters successfully set
[CONFIG] log_config: 53/53 parameters successfully set
[CONFIG] log_config: 53/53 parameters successfully set
[CONFIG] log_config: 16/16 parameters successfully set
[CONFIG] log_config: 16/16 parameters successfully set
log init done
[CONFIG] loader: 2/2 parameters successfully set
[CONFIG] loader.ldpc: 1/2 parameters successfully set
[HW] Device 0, max Work Items size for dimension: 0 8192
[HW] Device 0, max Work Items size for dimension: 1 8192
[HW] Device 0, max Work Items size for dimension: 2 8192
[HW] Platform 1, OpenCL profile FULL_PROFILE
[HW] Platform 1, OpenCL version OpenCL 2.0 beignet 1.3
[HW] Device 0 is available
[HW] Device 0, type 4 = 0x00000004: gpu
[HW] Device 0, number of Compute Units: 20
[HW] Device 0, max Work Items dimension: 3
[HW] Device 0, max Work Items size for dimension: 0 512
[HW] Device 0, max Work Items size for dimension: 1 512
[HW] Device 0, max Work Items size for dimension: 2 512
................................
```
```
### LDPC libraries
Libraries implementing the LDPC algorithms must be named `libldpc<_version>.so`, they must implement three functions: `nrLDPC_initcall``nrLDPC_decod` and `nrLDPC_encod`. The prototypes for these functions is defined in [nrLDPC_defs.h](file://nrLDPC_defs.h).
`libldpc_cuda.so`has been tested with the `ldpctest` executable, usage from the softmodem's has to be tested.
###LDPC libraries
Libraries implementing the LDPC algorithms must be named `libldpc<_version>.so`, they must implement two functions: `nrLDPC_decod` and `nrLDPC_encod`. The prototypes for these functions is defined in [nrLDPC_defs.h](file://nrLDPC_defs.h).
