|
| 1 | +from gurobipy import Model, GRB, quicksum |
| 2 | + |
| 3 | +def AddBias(X): |
| 4 | + return [x for x in X] + [1] |
| 5 | + |
| 6 | +def Sign(x): |
| 7 | + return 1 if x >= 0.01 else -1 |
| 8 | + |
| 9 | +def MIPxor(Xs, Ys, Phi=lambda x: x, NH=2): |
| 10 | + Xs = [Phi(x) for x in Xs] |
| 11 | + |
| 12 | + m = len(Xs[0]) |
| 13 | + n = len(Xs) |
| 14 | + |
| 15 | + nh = NH |
| 16 | + |
| 17 | + # Create model ILP |
| 18 | + model = Model() |
| 19 | + model.setParam(GRB.Param.TimeLimit, 5) # In seconds |
| 20 | + model.setParam(GRB.Param.OutputFlag, 1) # 0: silent, 1: normal, 2: verbose |
| 21 | + |
| 22 | + wp, wn = {}, {} |
| 23 | + for i in range(m): |
| 24 | + for h in range(nh): |
| 25 | + wp[i, h] = model.addVar(obj=0.001, vtype=GRB.BINARY) |
| 26 | + wn[i, h] = model.addVar(obj=0.001, vtype=GRB.BINARY) |
| 27 | + |
| 28 | + up = [model.addVar(obj=0.001, vtype=GRB.BINARY) for h in range(nh)] |
| 29 | + un = [model.addVar(obj=0.001, vtype=GRB.BINARY) for h in range(nh)] |
| 30 | + |
| 31 | + # Bias on output |
| 32 | + ubp = model.addVar(obj=0.001, vtype=GRB.BINARY) |
| 33 | + ubn = model.addVar(obj=0.001, vtype=GRB.BINARY) |
| 34 | + |
| 35 | + z = {} |
| 36 | + vp, vn = {}, {} |
| 37 | + for k in range(n): |
| 38 | + for h in range(nh): |
| 39 | + z[k, h] = model.addVar(vtype=GRB.BINARY) |
| 40 | + # Variable to linearize the product of binary variables |
| 41 | + vp[k, h] = model.addVar(vtype=GRB.BINARY) |
| 42 | + vn[k, h] = model.addVar(vtype=GRB.BINARY) |
| 43 | + |
| 44 | + y_hat = [model.addVar(vtype=GRB.BINARY) for k in range(n)] |
| 45 | + alpha = [model.addVar(lb=0, obj=1) for k in range(n)] |
| 46 | + |
| 47 | + # First layer constraints |
| 48 | + M = 1000 |
| 49 | + for k in range(n): |
| 50 | + for h in range(nh): |
| 51 | + model.addConstr( quicksum(Xs[k][i]*(wp[i,h]-wn[i,h]) for i in range(m)) >= 0.01 - M*(1 - z[k,h]) ) |
| 52 | + model.addConstr( quicksum(Xs[k][i]*(wp[i,h]-wn[i,h]) for i in range(m)) <= 0.00 + M*z[k,h] ) |
| 53 | + |
| 54 | + # Second layer constraints |
| 55 | + for k in range(n): |
| 56 | + # (2z-1)*(up - un) = 2z*up - 2z*un - up + un |
| 57 | + model.addConstr( (ubp - ubn) + quicksum((2*vp[k,h] - 2*vn[k,h] - up[h] + un[h]) for h in range(nh)) >= 0.01 - M*(1 - y_hat[k])) |
| 58 | + model.addConstr( (ubp - ubn) + quicksum((2*vp[k,h] - 2*vn[k,h] - up[h] + un[h]) for h in range(nh)) <= 0.00 + M*y_hat[k]) |
| 59 | + |
| 60 | + for k in range(n): |
| 61 | + for h in range(nh): |
| 62 | + model.addConstr( vp[k,h] >= z[k,h] + up[h] - 1 ) |
| 63 | + model.addConstr( vp[k,h] <= z[k,h] ) |
| 64 | + model.addConstr( vp[k,h] <= up[h] ) |
| 65 | + |
| 66 | + model.addConstr( vn[k,h] >= z[k,h] + un[h] - 1 ) |
| 67 | + model.addConstr( vn[k,h] <= z[k,h] ) |
| 68 | + model.addConstr( vn[k,h] <= un[h] ) |
| 69 | + |
| 70 | + for k in range(n): |
| 71 | + model.addConstr( (2*y_hat[k]-1) - Ys[k] <= alpha[k]) |
| 72 | + model.addConstr( Ys[k] - (2*y_hat[k]-1) <= alpha[k]) |
| 73 | + |
| 74 | + model.optimize() |
| 75 | + |
| 76 | + if model.status != GRB.OPTIMAL and model.status != GRB.TIME_LIMIT: |
| 77 | + return None |
| 78 | + |
| 79 | + wbar = {(i, h): wp[i, h].X - wn[i,h].X for i, h in wp} |
| 80 | + ubar = [up[h].X - un[h].X for h in range(nh)] |
| 81 | + ubias = ubp.X - ubn.X |
| 82 | + print('wbar nonzero', sum(wbar[i,h] != 0 for i, h in wbar)) |
| 83 | + print('ubar nonzero', sum(u != 0 for u in ubar) + (ubias != 0)) |
| 84 | + |
| 85 | + def F(x): |
| 86 | + z = Phi(x) |
| 87 | + return Sign(sum(ubar[h]*Sign(sum(z[i]*wbar[i,h] for i in range(m))) for h in range(nh))) |
| 88 | + |
| 89 | + return F |
| 90 | + |
| 91 | +def MIPxor_noncnvex(Xs, Ys, Phi=lambda x: x, NH=2): |
| 92 | + Xs = [Phi(x) for x in Xs] |
| 93 | + |
| 94 | + m = len(Xs[0]) |
| 95 | + n = len(Xs) |
| 96 | + |
| 97 | + nh = NH |
| 98 | + |
| 99 | + # Create model ILP |
| 100 | + model = Model() |
| 101 | + model.setParam(GRB.Param.TimeLimit, 5) # In seconds |
| 102 | + model.setParam(GRB.Param.OutputFlag, 1) # 0: silent, 1: normal, 2: verbose |
| 103 | + |
| 104 | + # For automatic linearization techniques |
| 105 | + model.setParam(GRB.Param.NonConvex, 2) |
| 106 | + |
| 107 | + wp, wn = {}, {} |
| 108 | + for i in range(m): |
| 109 | + for h in range(nh): |
| 110 | + wp[i, h] = model.addVar(obj=0.001, vtype=GRB.BINARY) |
| 111 | + wn[i, h] = model.addVar(obj=0.001, vtype=GRB.BINARY) |
| 112 | + |
| 113 | + up = [model.addVar(obj=0.001, vtype=GRB.BINARY) for h in range(nh)] |
| 114 | + un = [model.addVar(obj=0.001, vtype=GRB.BINARY) for h in range(nh)] |
| 115 | + |
| 116 | + z = {} |
| 117 | + for k in range(n): |
| 118 | + for h in range(nh): |
| 119 | + z[k, h] = model.addVar(vtype=GRB.BINARY) |
| 120 | + |
| 121 | + y_hat = [model.addVar(vtype=GRB.BINARY) for k in range(n)] |
| 122 | + alpha = [model.addVar(lb=0, obj=1) for k in range(n)] |
| 123 | + |
| 124 | + # First layer constraints |
| 125 | + M = 1000 |
| 126 | + for k in range(n): |
| 127 | + for h in range(nh): |
| 128 | + model.addConstr( quicksum(Xs[k][i]*(wp[i,h]-wn[i,h]) for i in range(m)) >= 0.01 - M*(1 - z[k,h]) ) |
| 129 | + model.addConstr( quicksum(Xs[k][i]*(wp[i,h]-wn[i,h]) for i in range(m)) <= 0.00 + M*z[k,h] ) |
| 130 | + |
| 131 | + # Second layer constraints |
| 132 | + for k in range(n): |
| 133 | + model.addConstr( quicksum(z[k,h]*(up[h] - un[h]) for h in range(nh)) >= 0.01 - M*(1 - y_hat[k])) |
| 134 | + model.addConstr( quicksum(z[k,h]*(up[h] - un[h]) for h in range(nh)) <= 0.00 + M*y_hat[k]) |
| 135 | + |
| 136 | + for k in range(n): |
| 137 | + model.addConstr( (2*y_hat[k]-1) - Ys[k] <= alpha[k]) |
| 138 | + model.addConstr( Ys[k] - (2*y_hat[k]-1) <= alpha[k]) |
| 139 | + |
| 140 | + model.optimize() |
| 141 | + |
| 142 | + if model.status != GRB.OPTIMAL and model.status != GRB.TIME_LIMIT: |
| 143 | + return None |
| 144 | + |
| 145 | + wbar = {(i, h): wp[i, h].X - wn[i,h].X for i, h in wp} |
| 146 | + ubar = [up[h].X - un[h].X for h in range(nh)] |
| 147 | + |
| 148 | + print('wbar nonzero', sum(wbar[i,h] != 0 for i, h in wbar)) |
| 149 | + print('ubar nonzero', sum(u != 0 for u in ubar)) |
| 150 | + |
| 151 | + def F(x): |
| 152 | + z = Phi(x) |
| 153 | + return Sign(sum(ubar[h]*Sign(sum(z[i]*wbar[i,h] for i in range(m))) for h in range(nh))) |
| 154 | + |
| 155 | + return F |
| 156 | + |
| 157 | + |
| 158 | +from numpy.random import normal, seed |
| 159 | +seed(13) |
| 160 | +def AddNoise(X, mu=0.1): |
| 161 | + return list(map(lambda x: x + normal(0, mu), X)) |
| 162 | + |
| 163 | +Xor = [(-1, -1), (-1, 1), (1, -1), (1, 1)] |
| 164 | +Yor = [-1, 1, 1, -1] |
| 165 | + |
| 166 | +# Sample points |
| 167 | +Xtrain, Ytrain = [], [] |
| 168 | +for _ in range(250): |
| 169 | + Xtrain.extend([AddNoise(x) for x in Xor]) |
| 170 | + Ytrain.extend(Yor) |
| 171 | + |
| 172 | +Xtest, Ytest = [], [] |
| 173 | +for _ in range(250): |
| 174 | + Xtest.extend([AddNoise(x) for x in Xor]) |
| 175 | + Ytest.extend(Yor) |
| 176 | + |
| 177 | +nh=2 |
| 178 | +F1 = MIPxor(Xtrain, Ytrain, Phi=AddBias, NH=nh) |
| 179 | +F2 = MIPxor(Xtrain, Ytrain, Phi=AddBias, NH=nh) |
| 180 | + |
| 181 | +acc1, acc2 = 0, 0 |
| 182 | +for x, y in zip(Xtest, Ytest): |
| 183 | + acc1 = acc1 + (F1(x) == y) |
| 184 | + acc2 = acc2 + (F2(x) == y) |
| 185 | +# print(x, F(x), y) |
| 186 | + |
| 187 | +print('Accuracy:', acc1/len(Xtest), len(Xtest), len(Xtrain), 'NH',nh) |
| 188 | +print('Accuracy Non convex:', acc2ù/len(Xtest), len(Xtest), len(Xtrain), 'NH',nh) |
| 189 | + |
| 190 | + |
| 191 | + |
| 192 | + |
| 193 | + |
| 194 | + |
| 195 | + |
| 196 | + |
0 commit comments