Remove option no2hop and fix it to true

Author: filikat

docs/src/options/definitions.md

@@ -445,11 +445,6 @@
 - Range: {0, 2147483647}
 - Default: 128
 
-## [hipo\_metis\_no2hop](@id option-hipo-metis-no2hop)
-- Set option no2hop in Metis when using HiPO
-- Type: boolean
-- Default: false
-
 ## pdlp\_scaling
 - Scaling option for PDLP solver: Default = true
 - Type: boolean

highs/ipm/IpxWrapper.cpp

@@ -567,9 +567,6 @@ HighsStatus solveLpHipo(const HighsOptions& options, HighsTimer& timer,
   // block size option
   hipo_options.block_size = options.hipo_block_size;
 
-  // metis options
-  hipo_options.metis_no2hop = options.hipo_metis_no2hop;
-
   hipo.setOptions(hipo_options);
   hipo.setTimer(timer);
   hipo.setCallback(callback);

highs/ipm/hipo/factorhighs/Analyse.cpp

@@ -6,13 +6,13 @@
 #include <random>
 #include <stack>
 
-#include "amd/amd.h"
 #include "DataCollector.h"
 #include "FactorHiGHSSettings.h"
-#include "metis/metis.h"
 #include "ReturnValues.h"
+#include "amd/amd.h"
 #include "ipm/hipo/auxiliary/Auxiliary.h"
 #include "ipm/hipo/auxiliary/Log.h"
+#include "metis/metis.h"
 #include "rcm/rcm.h"
 
 namespace hipo {
@@ -61,7 +61,7 @@ Analyse::Analyse(const std::vector<Int>& rows, const std::vector<Int>& ptr,
   ready_ = true;
 }
 
-Int Analyse::getPermutation(bool metis_no2hop) {
+Int Analyse::getPermutation() {
   // Compute fill-reducing reodering using metis, amd or rcm.
 
   perm_.resize(n_);
@@ -130,8 +130,8 @@ Int Analyse::getPermutation(bool metis_no2hop) {
     if (log_->debug(2))
       options[METIS_OPTION_DBGLVL] = METIS_DBG_INFO | METIS_DBG_COARSEN;
 
-    // set no2hop=1 if the user requested it
-    if (metis_no2hop) options[METIS_OPTION_NO2HOP] = 1;
+    // no2hop improves the quality of ordering in general
+    options[METIS_OPTION_NO2HOP] = 1;
 
     if (log_) log_->printDevInfo("Running Metis\n");
 
@@ -1302,7 +1302,7 @@ Int Analyse::run(Symbolic& S) {
 #if HIPO_TIMING_LEVEL >= 2
   Clock clock_items;
 #endif
-  if (getPermutation(S.metisNo2hop())) return kRetOrderingError;
+  if (getPermutation()) return kRetOrderingError;
 #if HIPO_TIMING_LEVEL >= 2
   data_.sumTime(kTimeAnalyseOrdering, clock_items.stop());
 #endif

highs/ipm/hipo/factorhighs/Analyse.h

@@ -88,7 +88,7 @@ class Analyse {
   const std::string& ordering_;
 
   // Functions to perform analyse phase
-  Int getPermutation(bool metis_no2hop);
+  Int getPermutation();
   void permute(const std::vector<Int>& iperm);
   void eTree();
   void postorder();

highs/ipm/hipo/factorhighs/Symbolic.cpp

@@ -14,10 +14,6 @@ void Symbolic::setParallel(bool par_tree, bool par_node) {
   parallel_node_ = par_node;
 }
 
-void Symbolic::setMetisNo2hop(bool metis_no2hop) {
-  metis_no2hop_ = metis_no2hop;
-}
-
 Int64 Symbolic::nz() const { return nz_; }
 double Symbolic::flops() const { return flops_; }
 double Symbolic::spops() const { return spops_; }
@@ -44,7 +40,6 @@ Int64 Symbolic::cliqueSize(Int sn) const {
 Int64 Symbolic::maxStackSize() const { return max_stack_size_; }
 bool Symbolic::parTree() const { return parallel_tree_; }
 bool Symbolic::parNode() const { return parallel_node_; }
-bool Symbolic::metisNo2hop() const { return metis_no2hop_; }
 double Symbolic::storage() const { return serial_storage_; }
 
 const std::vector<Int64>& Symbolic::ptr() const { return ptr_; }

highs/ipm/hipo/factorhighs/Symbolic.h

@@ -14,9 +14,6 @@ class Symbolic {
   bool parallel_tree_ = false;
   bool parallel_node_ = false;
 
-  // metis options
-  bool metis_no2hop_ = false;
-
   // Size of blocks for dense factorisation
   Int block_size_;
 
@@ -107,7 +104,6 @@ class Symbolic {
  public:
   Symbolic();
   void setParallel(bool par_tree, bool par_node);
-  void setMetisNo2hop(bool metis_no2hop);
 
   // provide const access to symbolic factorisation
   Int64 nz() const;
@@ -130,7 +126,6 @@ class Symbolic {
   Int64 maxStackSize() const;
   bool parTree() const;
   bool parNode() const;
-  bool metisNo2hop() const;
   double storage() const;
   const std::vector<Int64>& ptr() const;
   const std::vector<Int>& iperm() const;

highs/ipm/hipo/ipm/FactorHiGHSSolver.cpp

@@ -71,14 +71,6 @@ Int FactorHiGHSSolver::setup() {
 
   S_.print(log_, log_.debug(1));
 
-  // Warn about large fill-in
-  if (S_.fillin() > kLargeFillin && options_.ordering == "metis" &&
-      !options_.metis_no2hop) {
-    log_.printw(
-        "Large fill-in in factorisation. Consider setting the "
-        "hipo_metis_no2hop option to true\n");
-  }
-
   // Warn about large memory consumption
   if (S_.storage() > kLargeStorageGB * 1024 * 1024 * 1024) {
     log_.printw("Large amount of memory required\n");
@@ -539,9 +531,6 @@ Int FactorHiGHSSolver::chooseNla() {
   bool overflow_NE = false;
   bool overflow_AS = false;
 
-  symb_NE.setMetisNo2hop(options_.metis_no2hop);
-  symb_AS.setMetisNo2hop(options_.metis_no2hop);
-
   Clock clock;
 
   // Perform analyse phase of augmented system
@@ -633,8 +622,6 @@ Int FactorHiGHSSolver::chooseNla() {
 Int FactorHiGHSSolver::setNla() {
   std::stringstream log_stream;
 
-  S_.setMetisNo2hop(options_.metis_no2hop);
-
   switch (options_.nla) {
     case kOptionNlaAugmented: {
       if (analyseAS(S_)) {

highs/ipm/hipo/ipm/Options.h

@@ -42,9 +42,6 @@ struct Options {
   OptionParallel parallel = kOptionParallelDefault;
   std::string ordering = kHighsChooseString;
 
-  // Metis options
-  bool metis_no2hop = false;
-
   // Ipm parameters
   Int max_iter = kMaxIterDefault;
   double feasibility_tol = kIpmTolDefault;

highs/lp_data/HighsOptions.h

@@ -379,7 +379,6 @@ struct HighsOptionsStruct {
   std::string hipo_parallel_type;
   std::string hipo_ordering;
   HighsInt hipo_block_size;
-  bool hipo_metis_no2hop;
 
   // Options for PDLP solver
   bool pdlp_scaling;
@@ -552,7 +551,6 @@ struct HighsOptionsStruct {
         hipo_parallel_type(""),
         hipo_ordering(""),
         hipo_block_size(0),
-        hipo_metis_no2hop(false),
         pdlp_scaling(false),
         pdlp_iteration_limit(0),
         pdlp_e_restart_method(0),
@@ -1282,11 +1280,6 @@ class HighsOptions : public HighsOptionsStruct {
         advanced, &hipo_block_size, 0, 128, kHighsIInf);
     records.push_back(record_int);
 
-    record_bool =
-        new OptionRecordBool("hipo_metis_no2hop", "Use option no2hop in Metis",
-                             advanced, &hipo_metis_no2hop, false);
-    records.push_back(record_bool);
-
     record_bool = new OptionRecordBool(
         "pdlp_scaling", "Scaling option for PDLP solver: Default = true",
         advanced, &pdlp_scaling, true);