using elkai for LKH

README.md

@@ -82,7 +82,7 @@ pip install -e .
 
 The command line use of VeRyPy assumes TSPLIB formatted files (assuming VeRyPy is in your PYTHONPATH):
 ```bash
-python -O VeRyPy.py -a all E-n51-k5.vrp
+python -O VeRyPy.py -a all examples/E-n51-k5.vrp
 ```
 
 > Note: running with `python -O` entirely disables `__debug__` and logging.

requirements.txt

@@ -3,4 +3,5 @@ natsort
 orderedset # compatible up to python 3.8
 numpy
 scipy
-llist
+llist
+elkai

verypy/tsp_solvers/tsp_solver_lkh.py

@@ -6,19 +6,15 @@
 from subprocess import Popen, PIPE
 from tempfile import NamedTemporaryFile
 from logging import log, DEBUG
+from turtle import end_fill
 import numpy as np
 import sys
 import os
 
-from cvrp_io import write_TSPLIB_file    
+from verypy.config import LKH_EXACT_DISTANCES_PRECISION_DECIMALS
 
-from verypy.config import LKH_EXE_PATH, LKH_EXACT_DISTANCES_PRECISION_DECIMALS
+import elkai
 
-# Make sure we have access to LKH executable (download, comiple, and modify config.py).
-if not os.path.isfile(LKH_EXE_PATH):
-    raise ImportError("No LKH executable found at \"%s\" (the path is defined in config.py)"%LKH_EXE_PATH) 
-if not os.access(LKH_EXE_PATH, os.X_OK):
-    raise ImportError("LKH executable is not set executable") 
 
 def solve_tsp_lkh(D, selected_idxs,
                   float_accuracy = LKH_EXACT_DISTANCES_PRECISION_DECIMALS,
@@ -49,85 +45,59 @@ def solve_tsp_lkh(D, selected_idxs,
             p=n
         return sol, sol_f
 
-    # 1. Create a TSPLIB file
-    are_float_distances = issubclass(D.dtype.type, np.float)
-    if not are_float_distances:
-        float_accuracy = None
-    with NamedTemporaryFile( delete=False, suffix='.tsp') as tmpfile:
-        temp_problem_file_path = tmpfile.name
-    write_TSPLIB_file(temp_problem_file_path, D,
-                      selected_idxs=selected_idxs, 
-                      float_to_int_precision=float_accuracy)
-
-    # 2. Create a parameter file for lkh.exe
-    with NamedTemporaryFile( delete=False, suffix='.par') as tmpfile:
-        temp_parameter_file_path = tmpfile.name
-    with NamedTemporaryFile( delete=False, suffix='.tspsol') as tmpfile:
-        temp_output_file_path = tmpfile.name
-    with open(temp_parameter_file_path, 'w') as problem_file:
-        problem_file.write("PROBLEM_FILE = %s\n" % temp_problem_file_path)
-        problem_file.write("OUTPUT_TOUR_FILE = %s\n" % temp_output_file_path)
-        problem_file.write("TRACE_LEVEL = 0\n")
-        #problem_file.write("SEED = 42\n")
-        if num_runs:
-            problem_file.write("RUNS = %d\n"%num_runs)
-
-
-    # 3. Call lkh
-    command = [LKH_EXE_PATH, temp_parameter_file_path]
-    p = Popen(command, stdout=PIPE, stdin=PIPE)
-
-    # In Python3 bytes go in and come out. Special handling is required.
-    #  (not pretty, but allows smoketests to pass on Py3)
-    if sys.version_info[0] >= 3:
-        stdout_data = p.communicate(input=b' ')[0].decode('ascii')
-    else:
-        stdout_data = p.communicate(input=' ')[0]
+    M = D[selected_idxs, :][:, selected_idxs]
 
+    are_float_distances = issubclass(M.dtype.type, np.float)
+    if are_float_distances:
+        M = int(M * float_accuracy)
+    else:
+        M = M
 
-    if __debug__:    
-        log(DEBUG-3, stdout_data)
-
-    #TODO: CHECK FOR LKH FAILURE?
-    #if "Press any key to continue" in stdout_data[-40:]:
-    #   lkh_successfull = True
-
+    if num_runs is None:
+        num_runs = 1
+
+    output = elkai.solve_int_matrix(M, runs=num_runs)
+
+
+
+
+
     # 4. Process output
     sol = []
     obj_f = 0
     tail = []
-    with open(temp_output_file_path, 'r') as output_file:
-        skip = True
+    for l in output:
         depot_found = False
-        for l in output_file.readlines():
-            l = l.strip()
-            if l == "EOF" or l == "-1":
-                skip = True
-            elif "Length = " in l:
-                obj_f = float(l.split()[-1])
-            elif not skip:
-                vrp_nid = selected_idxs[int(l)-1]
-                if vrp_nid==0:
-                    tail.append(0)
-                    depot_found = True
-                if depot_found:                    
-                    sol.append(vrp_nid)
-                else:
-                    tail.append(vrp_nid)
-            if l == "TOUR_SECTION":
-                skip = False
-        sol+=tail
-        if not depot_found:
-            sol+=[sol[0]]
-        
-    os.remove(temp_problem_file_path) 
-    os.remove(temp_parameter_file_path) 
-    os.remove(temp_output_file_path) 
-    
-    if are_float_distances:
-        obj_f = obj_f/float_accuracy;
-    
+
+        vrp_nid = selected_idxs[l]
+        if vrp_nid==0:
+            tail.append(0)
+            depot_found = True
+        if depot_found:                    
+            sol.append(vrp_nid)
+        else:
+            tail.append(vrp_nid)
+
+    sol += tail
+    if not depot_found:
+        sol+=[sol[0]]
+
+
+    # 5. Calculating the tour length
+    obj_f = 0 
+    for i in range(len(sol)-1):
+        obj_f += D[sol[i], sol[i+1]]
+
+
+    #TODO: CHECK FOR LKH FAILURE?
+    #if "Press any key to continue" in stdout_data[-40:]:
+    #   lkh_successfull = True
+
+
+
+
     return sol, obj_f
+
 
 if __name__=="__main__":
     from shared_cli import tsp_cli