add solve

ampl · Sep 29, 2024 · 4a00223 · 4a00223
1 parent 7bdb417
commit 4a00223
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Showing 7 changed files with 14 additions and 13 deletions.
diff --git a/examples/dietmodel.R b/examples/dietmodel.R
@@ -47,7 +47,7 @@ dietmodel <- function(solver=NULL, modelDirectory=NULL) {
   ampl$setData(df, 2, "")
 
   # Solve the model
-  ampl$solve()
+  ampl$solve("", "gurobi")
 
   # Print out the result
   cat(sprintf("Objective: %f\n", ampl$getObjective("Total_Cost")$value()))

diff --git a/examples/efficientfrontier.R b/examples/efficientfrontier.R
@@ -43,7 +43,7 @@ efficientfrontier <- function(solver=NULL, modelDirectory=NULL) {
   # Relax the integrality
   ampl$setOption("relax_integrality", TRUE)
   # Solve the problem
-  ampl$solve()
+  ampl$solve("", "gurobi")
   # Calibrate the efficient frontier range
   minret <- portfolioReturn$value()
   values <- averageReturn$getValues()
@@ -60,14 +60,14 @@ efficientfrontier <- function(solver=NULL, modelDirectory=NULL) {
     ampl$eval("let stockopall:={};let stockrun:=stockall;")
     # Relax integrality
     ampl$setOption("relax_integrality", TRUE)
-    ampl$solve()
+    ampl$solve("", "gurobi")
     cat(sprintf("QP result = %g\n", variance$value()))
     # Adjust included stocks
     ampl$eval("let stockrun:={i in stockrun:weights[i]>0};")
     ampl$eval("let stockopall:={i in stockrun:weights[i]>0.5};")
     # Set integrality back
     ampl$setOption("relax_integrality", FALSE)
-    ampl$solve()
+    ampl$solve("", "gurobi")
     cat(sprintf("QMIP result = %g\n", variance$value()))
     # Store data of corrent frontier point
     returns <- c(returns, maxret - (i - 1) * stepsize)

diff --git a/examples/firstexample.R b/examples/firstexample.R
@@ -19,7 +19,7 @@ firstexample <- function(solver=NULL, modelDirectory=NULL) {
   ampl$readData(paste(modelDirectory, "/diet/diet.dat", sep=""))
 
   # Solve
-  ampl$solve()
+  ampl$solve("", "gurobi")
 
   # Get objective entity by AMPL name
   totalcost <- ampl$getObjective("Total_Cost")
@@ -34,7 +34,7 @@ firstexample <- function(solver=NULL, modelDirectory=NULL) {
   cat(sprintf("Increased costs of beef and ham.\n"))
 
   # Resolve and display objective
-  ampl$solve()
+  ampl$solve("", "gurobi")
   cat(sprintf("New objective value: %f\n", totalcost$value()))
 
   # Reassign data - all instances
@@ -43,7 +43,7 @@ firstexample <- function(solver=NULL, modelDirectory=NULL) {
   cat(sprintf("Updated all costs.\n"))
 
   # Resolve and display objective
-  ampl$solve()
+  ampl$solve("", "gurobi")
   cat(sprintf("New objective value: %f\n", totalcost$value()))
 
   # Get the values of the variable Buy in a dataframe object

diff --git a/examples/trackingmodel.R b/examples/trackingmodel.R
@@ -36,7 +36,7 @@ trackingmodel <- function(solver=NULL, modelDirectory=NULL) {
   # Relax the integrality
   ampl$setOption("relax_integrality", TRUE)
   # Solve the problem
-  ampl$solve()
+  ampl$solve("", "gurobi")
   cat(sprintf("QP objective value ", ampl$getObjectives()[[1]]$value()))
 
   lowcutoff <- 0.04
@@ -62,6 +62,6 @@ trackingmodel <- function(solver=NULL, modelDirectory=NULL) {
   # Get back to the integer problem
   ampl$setOption("relax_integrality", FALSE)
   # Solve the (integer) problem
-  ampl$solve()
+  ampl$solve("", "gurobi")
   cat(sprintf("QMIP objective value %g\n", ampl$getObjectives()[[1]]$value()))
 }
diff --git a/src/rampl.cpp b/src/rampl.cpp
@@ -316,8 +316,9 @@ bool RAMPL::isRunning() const {
 
   :raises Error: If the underlying interpreter is not running.
 */
-void RAMPL::solve() {
-  _impl.eval("solve;");
+void RAMPL::solve(std::string problem = "", std::string solver = "") {
+  _impl.solve(problem, solver);
+  //_impl.eval("solve;");
   //return _impl.solve(); // FIXME: does not print to stdout with R IDE on Windows
 }
 

diff --git a/src/rampl.h b/src/rampl.h
@@ -104,7 +104,7 @@ class RAMPL {
   void reset();
   void close();
   bool isRunning() const;
-  void solve();
+  void solve(std::string problem, std::string solver);
 
   Rcpp::DataFrame getData(Rcpp::List statements) const;
   SEXP getValue(std::string scalarExpression) const;

diff --git a/tests/testthat/test_ampl.R b/tests/testthat/test_ampl.R
@@ -83,7 +83,7 @@ test_that("test AMPL", {
   expect_equal(ampl$getSets()$S$name(), "S")
   expect_equal(ampl$getParameters()$l$name(), "l")
 
-  ampl$solve()
+  ampl$solve("", "gurobi")
   expect_equal(ampl$getObjective("obj")$value(), 5)
 
   out <- ""