to deal with memory leaking: added instance method destroy! to Rglpk::Problem

lib/rglpk.rb

@@ -70,6 +70,14 @@ def initialize
       Glpk_wrapper.glp_create_index(@lp)
     end
 
+    def destroy!
+      Glpk_wrapper.glp_delete_prob(@lp)
+
+      Glpk_wrapper.delete_intArray(@_ia)
+      Glpk_wrapper.delete_intArray(@_ja)
+      Glpk_wrapper.delete_doubleArray(@_ar)
+    end
+
     def name=(n)
       Glpk_wrapper.glp_set_prob_name(@lp, n)
     end
@@ -162,6 +170,10 @@ def set_matrix(v)
         Glpk_wrapper.doubleArray_setitem(ar, y + 1, x)
       end
 
+      @_ia = ia
+      @_ja = ja
+      @_ar = ar
+
       Glpk_wrapper.glp_load_matrix(@lp, v.size, ia, ja, ar)
     end
 

test/test_memory_prof.rb

@@ -0,0 +1,75 @@
+require File.expand_path('helper', File.dirname(__FILE__))
+
+class TestMemoryProf < Test::Unit::TestCase
+  def test_memory_prof
+    while true
+      1000.times do |i|
+        _test_example
+      end
+
+      out = `ps aux | grep "ruby test/test_memory_prof.rb"`
+      puts out.split("\n")[0]
+    end
+  end
+
+  def _test_example
+    # The same Brief Example as found in section 1.3 of 
+    # glpk-4.44/doc/glpk.pdf.
+    #
+    # maximize
+    #   z = 10 * x1 + 6 * x2 + 4 * x3
+    #
+    # subject to
+    #   p:      x1 +     x2 +     x3 <= 100
+    #   q: 10 * x1 + 4 * x2 + 5 * x3 <= 600
+    #   r:  2 * x1 + 2 * x2 + 6 * x3 <= 300
+    #
+    # where all variables are non-negative
+    #   x1 >= 0, x2 >= 0, x3 >= 0
+    #    
+    p = Rglpk::Problem.new
+    p.name = "sample"
+    p.obj.dir = Rglpk::GLP_MAX
+
+    rows = p.add_rows(3)
+    rows[0].name = "p"
+    rows[0].set_bounds(Rglpk::GLP_UP, 0, 100)
+    rows[1].name = "q"
+    rows[1].set_bounds(Rglpk::GLP_UP, 0, 600)
+    rows[2].name = "r"
+    rows[2].set_bounds(Rglpk::GLP_UP, 0, 300)
+
+    cols = p.add_cols(3)
+    cols[0].name = "x1"
+    cols[0].set_bounds(Rglpk::GLP_LO, 0.0, 0.0)
+    cols[1].name = "x2"
+    cols[1].set_bounds(Rglpk::GLP_LO, 0.0, 0.0)
+    cols[2].name = "x3"
+    cols[2].set_bounds(Rglpk::GLP_LO, 0.0, 0.0)
+
+    p.obj.coefs = [10, 6, 4]
+
+    p.set_matrix([
+       1, 1, 1,
+      10, 4, 5,
+       2, 2, 6
+    ])
+
+    p.simplex
+    z = p.obj.get
+    x1 = cols[0].get_prim
+    x2 = cols[1].get_prim
+    x3 = cols[2].get_prim
+
+    result = "z = %g; x1 = %g; x2 = %g; x3 = %g" % [z, x1, x2, x3]
+    assert_equal "z = 733.333; x1 = 33.3333; x2 = 66.6667; x3 = 0", result
+    assert_equal Rglpk::GLP_NU, rows[0].get_stat
+    assert_equal 100, rows[0].get_prim
+    assert_equal 3.333333333333333, rows[0].get_dual
+    # File.delete("test.lp") rescue Errno::ENOENT
+    # p.write_lp("test.lp")
+    # assert File.exists?("test.lp")    
+
+    p.destroy!
+  end
+end