A-M baby

Task/Matrix-exponentiation-operator/Python/matrix-exponentiation-operator.py

@@ -0,0 +1,56 @@
+>>> from operator import mul
+>>> def matrixMul(m1, m2):
+  return map(
+    lambda row:
+      map(
+        lambda *column:
+          sum(map(mul, row, column)),
+        *m2),
+    m1)
+
+>>> def identity(size):
+	size = range(size)
+	return [[(i==j)*1 for i in size] for j in size]
+
+>>> def matrixExp(m, pow):
+	assert pow>=0 and int(pow)==pow, "Only non-negative, integer powers allowed"
+	accumulator = identity(len(m))
+	for i in range(pow):
+		accumulator = matrixMul(accumulator, m)
+	return accumulator
+
+>>> def printtable(data):
+	for row in data:
+		print ' '.join('%-5s' % ('%s' % cell) for cell in row)
+
+		
+>>> m = [[3,2], [2,1]]
+>>> for i in range(5):
+	print '\n%i:' % i
+	printtable( matrixExp(m, i) )
+
+	
+
+0:
+1     0
+0     1
+
+1:
+3     2
+2     1
+
+2:
+13    8
+8     5
+
+3:
+55    34
+34    21
+
+4:
+233   144
+144   89
+>>> printtable( matrixExp(m, 10) )
+1346269 832040
+832040 514229
+>>>