def primal_dual_simplex_solver(z_starN, matrix_B, matrix_N, x_star_b, b, c,
Beta, Nu, optimal_value):
"""Primal Problem solver."""
# Step 1: Convert z*N to nonnegative to make it Dual Feasible
temp_c = -1 * np.ones((len(c), 1))
z_starN = -1 * temp_c
z_starN, x_star_b, matrix_B, matrix_N, Nu, Beta, sol = pt2.dual_simplex_solver(
x_star_b, matrix_B, matrix_N, z_starN, b, temp_c, Beta, Nu,
optimal_value)
A_matrix = -1 * np.dot(linalg.inv(matrix_B), matrix_N)
row_matrix_a = []
indices_rows_matrix_a = []
# First Loop to pull x*B and corresponding A matrix row for the decision variables
# and multiply them to their coefficients in the objective function.
for i in range(len(c)):
if i + 1 in Beta:
index = np.where(Beta == i + 1)
optimal_value += c[i] * x_star_b[index].squeeze()
row_matrix_a.append(c[i] * (A_matrix[index, :].squeeze()))
indices_rows_matrix_a.append(Nu)
indices_rows_matrix_a = np.asarray(indices_rows_matrix_a)
array_row_matrix_a = np.asarray(row_matrix_a)
summed_array_to_substitute = []
# Second Loop to check if we have multiple rows pulled out from matrix_a. Then check the
# coefficients for the same decision variables and then add them.
for i in indices_rows_matrix_a[0, :]:
temp = 0
item = np.where(indices_rows_matrix_a == i)
temp += np.sum(array_row_matrix_a[item].squeeze())
if array_row_matrix_a[item].size != 0:
summed_array_to_substitute.append(temp)
# Now we got the summed array for the rows we substituted in original objective
# So, Third Loop is to check and sum if we have multiple coefficients for the same
# decision variables in this new objective function.
summed_array_to_substitute = np.asarray(summed_array_to_substitute)
for i in range(1, len(Nu) + 1):
item = np.where(Nu == i)
temp_sum = summed_array_to_substitute[item].squeeze(
) + c[item].squeeze()
if temp_sum.size != 0:
temp_c[i - 1] = summed_array_to_substitute[item].squeeze(
) + c[item].squeeze()
else:
temp_c[i - 1] = summed_array_to_substitute[i - 1].squeeze()
z_starN = -1 * temp_c
if np.min(z_starN) >= 0.0:
print "\t[Optimal Solution found]"
print "Optimal Solution is: ", optimal_value
print "z*N: \n", z_starN
else:
pt1.primal_simplex_solver(z_starN, matrix_B, matrix_N, x_star_b, b, c,
Beta, Nu, optimal_value)
return z_starN, x_star_b, matrix_B, matrix_N, Nu, Beta, optimal_value
def test_3_certificate_of_optimality(self):
"""Check for Primal Optimal Solution."""
print "Solving by Primal Simplex."
z_starN1, x_star_b1, matrix_B1, matrix_N1, Nu1, Beta1, opt_value1 = pt1.primal_simplex_solver(
self.z_star_n, self.matrix_B, self.matrix_N, self.x_starB, self.b,
self.c, self.Beta, self.Nu, self.objective)
self.assertAlmostEqual(self.optimal_solution, opt_value1, 3)
self.assertAlmostEqual(self.x_b_solution.all(), x_star_b1.all(), 3)
self.assertAlmostEqual(self.z_n_solution.all(), z_starN1.all(), 3)
def primal_dual_simplex_solver(z_starN, matrix_B, matrix_N, x_star_b, b, c,
Beta, Nu, optimal_value):
"""Primal Problem solver."""
# step 1
z_starN = np.absolute(z_starN)
z_starN, x_star_b, matrix_B, matrix_N, Beta, sol = pt2.dual_simplex_solver(
x_star_b, matrix_B, matrix_N, z_starN, b, c, Beta, Nu)
A_matrix = -1 * np.dot(linalg.inv(matrix_B), matrix_N)
# print "A_matrix: ", A_matrix
# optimal_value = 0
arr = []
index_arr = []
for i in range(len(c)):
if i + 1 in Beta:
index = np.where(Beta == i + 1)
optimal_value += c[i] * x_star_b[index].squeeze()
arr.append(c[i] * (A_matrix[index, :].squeeze()))
index_arr.append(Nu)
index_arr = np.asarray(index_arr)
arr_indx = np.asarray(arr)
another_arr = []
for i in index_arr[0, :]:
sumo = 0
item = np.where(index_arr == i)
sumo += np.sum(arr_indx[item].squeeze())
if arr_indx[item].size != 0:
another_arr.append(sumo)
another_arr = np.asarray(another_arr)
for i in range(1, len(Nu) + 1):
item = np.where(Nu == i)
sume = another_arr[item].squeeze() + c[item].squeeze()
if sume.size != 0:
z_starN[i - 1] = another_arr[item].squeeze() + c[item].squeeze()
else:
z_starN[i - 1] = another_arr[i - 1].squeeze()
if np.min(z_starN) >= 0.0:
print "Optimal Solution: ", optimal_value, z_starN
else:
c = 1 * z_starN
pt1.primal_simplex_solver(z_starN, matrix_B, matrix_N, x_star_b, b, c,
Beta, Nu)
return z_starN, x_star_b, matrix_B, matrix_N, Beta, optimal_value
def test_3_primal_solution(self):
"""Check for Primal Optimal Solution."""
print "Solving by Primal Simplex."
z_starN1, x_star_b1, matrix_B1, matrix_N1, Nu1, Beta1, opt_value1 = pt1.primal_simplex_solver(
self.z_star_n, self.matrix_B, self.matrix_N, self.x_starB, self.b,
self.c, self.Beta, self.Nu, self.objective)
xb = np.dot(linalg.inv(matrix_B1), self.b)
self.assertEqual(xb.all(), x_star_b1.all(), msg="x*b != inv(B) * b")
self.assertGreaterEqual(z_starN1.all(), 0.00000)
self.assertAlmostEqual(self.optimal_solution, opt_value1, 3)
self.assertAlmostEqual(self.x_b_solution.all(), x_star_b1.all(), 3)
self.assertAlmostEqual(self.z_n_solution.all(), z_starN1.all(), 3)
self.assertAlmostEqual(self.b_solution.all(), matrix_B1.all(), 3)
self.assertAlmostEqual(self.n_solution.all(), matrix_N1.all(), 3)
self.assertEqual(all(self.beta_solution), all(Beta1))
self.assertEqual(all(self.nu_solution), all(Nu1))
def test_3_complementary_slackness(self):
"""Check for Complementary Slackness."""
print "Solving by Primal Simplex."
z_starN1, x_star_b1, matrix_B1, matrix_N1, Nu1, Beta1, opt_value1 = pt1.primal_simplex_solver(self.z_star_n, self.matrix_B, self.matrix_N, self.x_starB, self.b, self.c, self.Beta, self.Nu, self.objective)
self.assertEqual(all(self.beta_solution), all(Beta1))
self.assertEqual(all(self.nu_solution), all(Nu1))
def __init__(self, parent=None):
"""The start point."""
parser = argparse.ArgumentParser(description='Linear Program Solver.')
parser.add_argument('A_csv', help='The csv for A matrix.')
parser.add_argument('b_csv', help='The csv for b vector.')
parser.add_argument('c_csv', help='The csv for c vector.')
args = parser.parse_args()
# Fetch the data for A matrix
data_a = csv.reader(open(args.A_csv, 'rb'))
a = []
for row in data_a:
a.append(row)
rows_a = len(a)
cols_a = len(row)
a = np.array([a]).reshape(rows_a, cols_a).astype(np.float)
# Fetch the data for b vector
data_b = csv.reader(open(args.b_csv, 'rb'))
self.b = []
for row in data_b:
self.b.append(row)
rows_b = len(self.b)
cols_b = len(row)
self.b = np.array([self.b]).reshape(rows_b, cols_b).astype(np.float)
# Fetch the data for c vector
data_c = csv.reader(open(args.c_csv, 'rb'))
self.c = []
for row in data_c:
self.c.append(row)
rows_c = len(self.c)
cols_c = len(row)
self.c = np.array([self.c]).reshape(rows_c, cols_c).astype(np.float)
self.Nu = np.arange(1, rows_c + 1)
self.Beta = np.arange(len(self.Nu) + 1, rows_b + len(self.Nu) + 1)
split_a = np.hsplit(a, [rows_c, rows_b + rows_c])
matrix_N = split_a[0]
matrix_B = split_a[1]
rows_N, cols_N = np.shape(matrix_N)
rows_B, cols_B = np.shape(matrix_B)
# Check for matrices consistency
if cols_N == rows_c and rows_a == rows_b == rows_B == cols_B == rows_N:
print("Everything is consistent!")
else:
print("[Error]: Data is inconsistent! Check the CSVs.")
sys.exit()
x_starB = self.b
z_star_n = -1 * self.c
objective = 0
# For Primal Infeasibility
if min(x_starB) < 0.0 and min(z_star_n) >= 0.0:
print "[Error]: The problem is Primal Infeasible."
print "So, performing Dual Simplex Method..."
pt2.dual_simplex_solver(x_starB, matrix_B, matrix_N, z_star_n, self.b, self.c, self.Beta, self.Nu, objective)
sys.exit()
# For Dual Infeasibility
if min(z_star_n) < 0.0 and min(x_starB) >= 0.0:
print "[Error]: The problem is Dual Infeasible."
print "So, performing Primal Simplex Method..."
pt1.primal_simplex_solver(z_star_n, matrix_B, matrix_N, x_starB, self.b, self.c, self.Beta, self.Nu, objective)
sys.exit()
# For Dual and Primal Infeasibility
if min(z_star_n) < 0.0 and min(x_starB) < 0.0:
print "The problem is Dual and Primal Infeasible."
pt3.primal_dual_simplex_solver(z_star_n, matrix_B, matrix_N, x_starB, self.b, self.c, self.Beta, self.Nu, objective)
sys.exit()