added truncate method and removed {0:.4f} to truncate floats to 4 decimal places

SnShine · SnShine · commit c4e8ec3c76b7 · 2016-03-29T12:17:36.000+05:30
diff --git a/probability.py b/probability.py
@@ -549,16 +549,15 @@ def forward(HMM, fv, ev):
                             scalar_vector_product(fv[1], HMM.transition_model[1]))
     sensor_dist = HMM.sensor_dist(ev)
 
-    return([float("{0:.4f}".format(i)) for i in normalize(element_wise_product(sensor_dist, prediction))])
+    return(normalize(element_wise_product(sensor_dist, prediction)))
 
 
 def backward(HMM, b, ev):
     sensor_dist = HMM.sensor_dist(ev)
     prediction = element_wise_product(sensor_dist, b)
 
-    return([float("{0:.4f}".format(i)) for i in normalize(vector_add(
-                                scalar_vector_product(prediction[0], HMM.transition_model[0]),
-                                scalar_vector_product(prediction[1], HMM.transition_model[1])))])
+    return(normalize(vector_add(scalar_vector_product(prediction[0], HMM.transition_model[0]),
+                                scalar_vector_product(prediction[1], HMM.transition_model[1]))))
 
 
 def forward_backward(HMM, ev, prior):
@@ -594,10 +593,6 @@ def forward_backward(HMM, ev, prior):
         bv.append(b)
 
     sv = sv[::-1]
-    # to have only 4 digits after decimal point
-    for i in range(len(sv)):
-        for j in range(len(sv[i])):
-            sv[i][j] = float("{0:.4f}".format(sv[i][j]))
 
     return(sv)
 
diff --git a/tests/test_probability.py b/tests/test_probability.py
@@ -110,12 +110,12 @@ def test_forward_backward():
     umbrellaHMM = HiddenMarkovModel(umbrella_transition, umbrella_sensor)
 
     umbrella_evidence = [T, T, F, T, T]
-    assert forward_backward(umbrellaHMM, umbrella_evidence, umbrella_prior) == [[0.6469, 0.3531],
-                [0.8673, 0.1327], [0.8204, 0.1796], [0.3075, 0.6925], [0.8205, 0.1795], [0.8673, 0.1327]]
+    assert truncate(forward_backward(umbrellaHMM, umbrella_evidence, umbrella_prior)) == [[0.6469, 0.3531],
+                [0.8673, 0.1327], [0.8204, 0.1796], [0.3075, 0.6925], [0.8204, 0.1796], [0.8673, 0.1327]]
 
     umbrella_evidence = [T, F, T, F, T]
-    assert forward_backward(umbrellaHMM, umbrella_evidence, umbrella_prior) == [[0.5871, 0.4129],
-                 [0.7177, 0.2823], [0.2325, 0.7675], [0.6072, 0.3928], [0.2324, 0.7676], [0.7177, 0.2823]]
+    assert truncate(forward_backward(umbrellaHMM, umbrella_evidence, umbrella_prior)) == [[0.5871, 0.4129],
+                 [0.7177, 0.2823], [0.2324, 0.7676], [0.6072, 0.3928], [0.2324, 0.7676], [0.7177, 0.2823]]
 
 def test_fixed_lag_smoothing():
     umbrella_evidence = [T, F, T, F, T]
@@ -126,16 +126,16 @@ def test_fixed_lag_smoothing():
     umbrellaHMM = HiddenMarkovModel(umbrella_transition, umbrella_sensor)
 
     d = 2
-    assert fixed_lag_smoothing(e_t, umbrellaHMM, d, umbrella_evidence, t) == [0.1111, 0.8889]
+    assert truncate(fixed_lag_smoothing(e_t, umbrellaHMM, d, umbrella_evidence, t)) == [0.1111, 0.8889]
     d = 5
-    assert fixed_lag_smoothing(e_t, umbrellaHMM, d, umbrella_evidence, t) is None
+    assert truncate(fixed_lag_smoothing(e_t, umbrellaHMM, d, umbrella_evidence, t)) is None
 
     umbrella_evidence = [T, T, F, T, T]
     # t = 4
     e_t = T
 
     d = 1
-    assert fixed_lag_smoothing(e_t, umbrellaHMM, d, umbrella_evidence, t) == [0.9939, 0.0061]
+    assert truncate(fixed_lag_smoothing(e_t, umbrellaHMM, d, umbrella_evidence, t)) == [0.9939, 0.0061]
 
 
 if __name__ == '__main__':
diff --git a/tests/test_utils.py b/tests/test_utils.py
@@ -118,14 +118,22 @@ def test_scalar_vector_product():
     assert scalar_vector_product(2, [1, 2, 3]) == [2, 4, 6]
 
 def test_scalar_matrix_product():
-  assert scalar_matrix_product(-5, [[1, 2], [3, 4], [0, 6]]) == [[-5, -10], [-15, -20], [0, -30]]
-  assert scalar_matrix_product(0.2, [[1, 2], [2, 3]]) == [[0.2, 0.4], [0.4, 0.6]]
+  assert truncate(scalar_matrix_product(-5, [[1, 2], [3, 4], [0, 6]])) == [[-5, -10], [-15, -20], [0, -30]]
+  assert truncate(scalar_matrix_product(0.2, [[1, 2], [2, 3]])) == [[0.2, 0.4], [0.4, 0.6]]
 
 
 def test_inverse_matrix():
-  assert inverse_matrix([[1, 0], [0, 1]]) == [[1, 0], [0, 1]]
-  assert inverse_matrix([[2, 1], [4, 3]]) == [[1.5, -0.5], [-2.0, 1.0]]
-  assert inverse_matrix([[4, 7], [2, 6]]) == [[0.6, -0.7], [-0.2, 0.4]]
+  assert truncate(inverse_matrix([[1, 0], [0, 1]])) == [[1, 0], [0, 1]]
+  assert truncate(inverse_matrix([[2, 1], [4, 3]])) == [[1.5, -0.5], [-2.0, 1.0]]
+  assert truncate(inverse_matrix([[4, 7], [2, 6]])) == [[0.6, -0.7], [-0.2, 0.4]]
+
+def test_truncate():
+  assert truncate(5.3330000300330) == 5.3330
+  assert truncate(10.234566) == 10.2346
+  assert truncate([1.234566, 0.555555, 6.010101]) == [1.2346, 0.5556, 6.0101]
+  assert truncate([[1.234566, 0.555555, 6.010101],
+                   [10.505050, 12.121212, 6.030303]]) == [[1.2346, 0.5556, 6.0101],
+                                                          [10.5051, 12.1212, 6.0303]]
 
 def test_num_or_str():
     assert num_or_str('42') == 42
diff --git a/utils.py b/utils.py
@@ -197,7 +197,7 @@ def _mat_mult(X_M, Y_M):
     for Y in Y_M:
         result = _mat_mult(result, Y)
 
-    return([[float("{0:.4f}".format(i)) for i in row] for row in result])
+    return(result)
 
 def vector_to_diagonal(v):
     """Converts a vector to a diagonal matrix with vector elements
@@ -218,7 +218,7 @@ def scalar_vector_product(X, Y):
     return [X*y for y in Y]
 
 def scalar_matrix_product(X, Y):
-    return([[float("{0:.4f}".format(i)) for i in scalar_vector_product(X, y)] for y in Y])
+    return([scalar_vector_product(X, y) for y in Y])
 
 def inverse_matrix(X):
     """Inverse a given square matrix of size 2x2"""
@@ -228,7 +228,7 @@ def inverse_matrix(X):
     assert det != 0
     inv_mat = scalar_matrix_product(1.0/det, [[X[1][1], -X[0][1]], [-X[1][0], X[0][0]]])
 
-    return([[float("{0:.4f}".format(i)) for i in row] for row in inv_mat])
+    return(inv_mat)
 
 
 def probability(p):
@@ -253,6 +253,16 @@ def weighted_sampler(seq, weights):
 
     return lambda: seq[bisect.bisect(totals, random.uniform(0, totals[-1]))]
 
+def truncate(x, n = 4):
+    """Truncates floats, vectors, matrices to n decimal values"""
+    if isinstance(x, float):
+        return(float("{0:.{1}f}".format(x, n)))
+    elif isinstance(x, list) and not isinstance(x[0], list):
+        return([float("{0:.{1}f}".format(i, n)) for i in x])
+    elif isinstance(x, list) and isinstance(x[0], list):
+        return([[float("{0:.{1}f}".format(i, n)) for i in row] for row in x])
+    else:
+        return x
 
 def num_or_str(x):
     """The argument is a string; convert to a number if
@@ -270,7 +280,7 @@ def num_or_str(x):
 def normalize(numbers):
     """Multiply each number by a constant such that the sum is 1.0"""
     total = float(sum(numbers))
-    return([float("{0:.4f}".format(n / total)) for n in numbers])
+    return([(n / total) for n in numbers])
 
 
 def clip(x, lowest, highest):
