Merge pull request #1917 from ERGO-Code/fix-1915

Added PDLP to docs!

docs/src/solvers.md

@@ -7,7 +7,7 @@ LP. HiGHS will choose the most appropriate technique for a given
 problem, but this can be over-ridden by setting the option
 [__solver__](@ref option-solver).
 
-### Simplex
+#### Simplex
 
 HiGHS has efficient implementations of both the primal and dual
 simplex methods, although the dual simplex solver is likely to be
@@ -19,24 +19,38 @@ J. A. J. Hall, Mathematical Programming Computation, 10 (1), 119-142,
 2018 [DOI:
 10.1007/s12532-017-0130-5](https://link.springer.com/article/10.1007/s12532-017-0130-5).
 
-The option [__simplex\_strategy__](@ref option-simplex_strategy) determines whether the primal solver or one of hte parallel solvers is to be used. 
+* Setting the option [__solver__](@ref option-solver) to "simplex" forces the simplex solver to be used
+* The option [__simplex\_strategy__](@ref option-simplex_strategy)
+determines whether the primal solver or one of the parallel solvers is
+to be used.
 
-### Interior point
+#### Interior point
 
-HiGHS has one interior point solver based on the preconditioned conjugate gradient method, as discussed in
+HiGHS has one interior point (IPM) solver based on the preconditioned conjugate gradient method, as discussed in
 
 _Implementation of an interior point method with basis
-preconditioning_, Mathematical Programming Computation, 12, 603-635,
-2020. [DOI:
+preconditioning_, Mathematical Programming Computation, 12, 603-635, 2020. [DOI:
 10.1007/s12532-020-00181-8](https://link.springer.com/article/10.1007/s12532-020-00181-8).
 
 This solver is serial. An interior point solver based on direct factorization is being developed.
 
-### MIP
+Setting the option [__solver__](@ref option-solver) to "ipm" forces the IPM solver to be used
+
+#### Primal-dual hybrid gradient method
+
+HiGHS includes the [cuPDLP-C](https://github.com/COPT-Public/cuPDLP-C)
+primal-dual hybrid gradient method for LP (PDLP). Currently this only
+runs on CPU, so it is unlikely to be competitive with the HiGHS
+interior point or simplex solvers. Enabling HiGHS to run PDLP on a GPU
+is work in progress.
+
+Setting the option [__solver__](@ref option-solver) to "pdlp" forces the PDLP solver to be used
+
+## MIP
 
 The HiGHS MIP solver uses established branch-and-cut techniques
 
-### QP
+## QP
 
 The HiGHS solver for convex QP problems uses an established primal
 active set method. The new interior point solver will also be able to