Submission of Homework1 for Michael Meldrum

sieve-fn.py

@@ -20,3 +20,4 @@ def next():
 
 for n in range(10):
     print next()
+

sieve_gen/example.py

@@ -0,0 +1,4 @@
+import sieve
+
+for n, i in zip(range(10), sieve.sieve()):
+    print i

sieve_gen/sieve.py

@@ -0,0 +1,19 @@
+# this is an implementation of the Eratosthenes' Sieve using
+# a generator.
+
+_primeslist = [2]
+
+def _is_prime(primes, n):
+    for i in primes:
+        if n % i == 0:
+            return False
+    return True
+
+def sieve():
+    start = _primeslist[-1] + 1
+    while 1:
+        if _is_prime(_primeslist, start):
+            _primeslist.append(start)
+            yield start
+
+        start += 1

sieve_gen/test1.py

@@ -0,0 +1,8 @@
+import sieve
+
+def test1():
+    s = sieve.sieve()
+    i = iter(s)
+    assert i.next() == 3
+
+test1()

sieve_gen/test2.py

@@ -0,0 +1,12 @@
+import sieve
+
+def test2():
+    s = sieve.sieve()
+    i = iter(s)
+
+    for x in range(3):
+	i.next()
+
+    assert i.next() == 11 # the fifth prime number should be 11
+
+test2()

sieve_gen/test3.py

@@ -0,0 +1,10 @@
+import sieve
+
+def test3():
+    s = sieve.sieve()
+    i = iter(s)
+    for x in range(15):
+	i.next()
+    assert i.next() == 59 # the seventeenth prime number should be 59
+
+test3()

sieve_iter/example.py

@@ -0,0 +1,4 @@
+import sieve
+
+for n, i in zip(range(10), sieve.sieve()):
+    print i

sieve_iter/sieve.py

@@ -0,0 +1,25 @@
+# this is an implementation of Eratosthenes' Sieve using
+# Python's iterator functionality.  Here, 'sieve' is a class that
+# obeys the iterator protocol.
+
+class sieve(object):
+    def __init__(self):
+        self.primeslist = [2]
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        start = self.primeslist[-1] + 1
+	while 1:
+	    if self.is_prime(start):
+		self.primeslist.append(start)
+		return start
+
+	    start += 1
+
+    def is_prime(self, n):
+	for i in self.primeslist:
+	    if n % i == 0:
+		return False
+	return True

sieve_iter/test1.py

@@ -0,0 +1,8 @@
+import sieve
+
+def test1():
+    s = sieve.sieve()
+    i = iter(s)
+    assert i.next() == 3
+
+test1()

sieve_iter/test2.py

@@ -0,0 +1,10 @@
+import sieve
+
+def test2():
+    s = sieve.sieve()
+    i = iter(s)
+    for x in range(3):
+	i.next()
+    assert i.next() == 11 # the fifth prime number should be 11
+
+test2()

sieve_iter/test3.py

@@ -0,0 +1,10 @@
+import sieve
+
+def test3():
+    s = sieve.sieve()
+    i = iter(s)
+    for x in range(15):
+	i.next()
+    assert i.next() == 59 # the seventeenth prime number should be 59
+
+test3()

sieve_mod/example.py

@@ -0,0 +1,4 @@
+import sieve
+
+for n in range(10):
+    print sieve.next()

sieve_mod/sieve.py

@@ -0,0 +1,20 @@
+# Implementation of Eratosthenes' Sieve by Michael Meldrum:
+# Modular form
+
+_primeslist = [2]
+
+def _is_prime(primes, n):
+    for i in primes:
+        if n % i == 0:
+            return False
+    return True
+
+def next():
+    global _primeslist
+    start = _primeslist[-1] + 1
+    while 1:
+        if _is_prime(_primeslist, start):
+            _primeslist.append(start)
+            return start
+
+        start += 1