import random
import operator
import sys
import unittest
__version__ = "0.3"
class MatrixError(Exception):
""" An exception class for Matrix """
pass
class Matrix(object):
""" A simple Python matrix class with
basic operations and operator overloading """
def __init__(self, m, n, init=True):
if init:
self.rows = [[0]*n for x in range(m)]
else:
self.rows = []
self.m = m
self.n = n
def __getitem__(self, idx):
return self.rows[idx]
def __setitem__(self, idx, item):
self.rows[idx] = item
def __str__(self):
s='\n'.join([' '.join([str(item) for item in row]) for row in self.rows])
return s + '\n'
def __repr__(self):
s=str(self.rows)
rank = str(self.getRank())
rep="Matrix: \"%s\", rank: \"%s\"" % (s,rank)
return rep
def reset(self):
""" Reset the matrix data """
self.rows = [[] for x in range(self.m)]
def transpose(self):
""" Transpose the matrix. Changes the current matrix """
self.m, self.n = self.n, self.m
self.rows = [list(item) for item in zip(*self.rows)]
def getTranspose(self):
""" Return a transpose of the matrix without
modifying the matrix itself """
m, n = self.n, self.m
mat = Matrix(m, n)
mat.rows = [list(item) for item in zip(*self.rows)]
return mat
def getRank(self):
return (self.m, self.n)
def __eq__(self, mat):
""" Test equality """
return (mat.rows == self.rows)
def __add__(self, mat):
""" Add a matrix to this matrix and
return the new matrix. Doesn't modify
the current matrix """
if self.getRank() != mat.getRank():
raise MatrixError, "Trying to add matrixes of varying rank!"
ret = Matrix(self.m, self.n)
for x in range(self.m):
row = [sum(item) for item in zip(self.rows[x], mat[x])]
ret[x] = row
return ret
def __sub__(self, mat):
""" Subtract a matrix from this matrix and
return the new matrix. Doesn't modify
the current matrix """
if self.getRank() != mat.getRank():
raise MatrixError, "Trying to add matrixes of varying rank!"
ret = Matrix(self.m, self.n)
for x in range(self.m):
row = [item[0]-item[1] for item in zip(self.rows[x], mat[x])]
ret[x] = row
return ret
def __mul__(self, mat):
""" Multiple a matrix with this matrix and
return the new matrix. Doesn't modify
the current matrix """
matm, matn = mat.getRank()
if (self.n != matm):
raise MatrixError, "Matrices cannot be multipled!"
mat_t = mat.getTranspose()
mulmat = Matrix(self.m, matn)
for x in range(self.m):
for y in range(mat_t.m):
mulmat[x][y] = sum([item[0]*item[1] for item in zip(self.rows[x], mat_t[y])])
return mulmat
def __iadd__(self, mat):
""" Add a matrix to this matrix.
This modifies the current matrix """
# Calls __add__
tempmat = self + mat
self.rows = tempmat.rows[:]
return self
def __isub__(self, mat):
""" Add a matrix to this matrix.
This modifies the current matrix """
# Calls __sub__
tempmat = self - mat
self.rows = tempmat.rows[:]
return self
def __imul__(self, mat):
""" Add a matrix to this matrix.
This modifies the current matrix """
# Possibly not a proper operation
# since this changes the current matrix
# rank as well...
# Calls __mul__
tempmat = self * mat
self.rows = tempmat.rows[:]
self.m, self.n = tempmat.getRank()
return self
def save(self, filename):
open(filename, 'w').write(str(self))
@classmethod
def _makeMatrix(cls, rows):
m = len(rows)
n = len(rows[0])
# Validity check
if any([len(row) != n for row in rows[1:]]):
raise MatrixError, "inconsistent row length"
mat = Matrix(m,n, init=False)
mat.rows = rows
return mat
@classmethod
def makeRandom(cls, m, n, low=0, high=10):
""" Make a random matrix with elements in range (low-high) """
obj = Matrix(m, n, init=False)
for x in range(m):
obj.rows.append([random.randrange(low, high) for i in range(obj.n)])
return obj
@classmethod
def makeZero(cls, m, n):
""" Make a zero-matrix of rank (mxn) """
rows = [[0]*n for x in range(m)]
return cls.fromList(rows)
@classmethod
def makeId(cls, m):
""" Make identity matrix of rank (mxm) """
rows = [[0]*m for x in range(m)]
idx = 0
for row in rows:
row[idx] = 1
idx += 1
return cls.fromList(rows)
@classmethod
def readStdin(cls):
""" Read a matrix from standard input """
print 'Enter matrix row by row. Type "q" to quit'
rows = []
while True:
line = sys.stdin.readline().strip()
if line=='q': break
row = [int(x) for x in line.split()]
rows.append(row)
return cls._makeMatrix(rows)
@classmethod
def readGrid(cls, fname):
""" Read a matrix from a file """
rows = []
for line in open(fname).readlines():
row = [int(x) for x in line.split()]
rows.append(row)
return cls._makeMatrix(rows)
@classmethod
def fromList(cls, listoflists):
""" Create a matrix by directly passing a list
of lists """
# E.g: Matrix.fromList([[1 2 3], [4,5,6], [7,8,9]])
rows = listoflists[:]
return cls._makeMatrix(rows)
class MatrixTests(unittest.TestCase):
def testAdd(self):
m1 = Matrix.fromList([[1, 2, 3], [4, 5, 6]])
m2 = Matrix.fromList([[7, 8, 9], [10, 11, 12]])
m3 = m1 + m2
self.assertTrue(m3 == Matrix.fromList([[8, 10, 12], [14,16,18]]))
def testSub(self):
m1 = Matrix.fromList([[1, 2, 3], [4, 5, 6]])
m2 = Matrix.fromList([[7, 8, 9], [10, 11, 12]])
m3 = m2 - m1
self.assertTrue(m3 == Matrix.fromList([[6, 6, 6], [6, 6, 6]]))
def testMul(self):
m1 = Matrix.fromList([[1, 2, 3], [4, 5, 6]])
m2 = Matrix.fromList([[7, 8], [10, 11], [12, 13]])
self.assertTrue(m1 * m2 == Matrix.fromList([[63, 69], [150, 165]]))
self.assertTrue(m2*m1 == Matrix.fromList([[39, 54, 69], [54, 75, 96], [64, 89, 114]]))
def testTranspose(self):
m1 = Matrix.makeRandom(25, 30)
zerom = Matrix.makeZero(25, 30)
m2 = m1 + zerom
m1.transpose()
m1.transpose()
self.assertTrue(m2 == m1)
# Also test getTranspose
m2 = m1.getTranspose()
r2 = m2.getRank()
self.assertTrue(r2==(30,25))
m2.transpose()
self.assertTrue(m2 == m1)
def testId(self):
m1 = Matrix.makeId(10)
m2 = Matrix.makeRandom(4, 10)
m3 = m2*m1
self.assertTrue(m3 == m2)
if __name__ == "__main__":
unittest.main()
Diff to Previous Revision
--- revision 2 2012-05-14 10:34:06
+++ revision 3 2012-05-14 13:34:31
@@ -3,7 +3,7 @@
import sys
import unittest
-__version__ = "0.2"
+__version__ = "0.3"
class MatrixError(Exception):
""" An exception class for Matrix """
@@ -13,8 +13,11 @@
""" A simple Python matrix class with
basic operations and operator overloading """
- def __init__(self, m, n):
- self.rows = [[0]*n for x in range(m)]
+ def __init__(self, m, n, init=True):
+ if init:
+ self.rows = [[0]*n for x in range(m)]
+ else:
+ self.rows = []
self.m = m
self.n = n
@@ -41,30 +44,17 @@
def transpose(self):
""" Transpose the matrix. Changes the current matrix """
- # Rows become columns and columns become rows
- indexed = [i for row in self.rows for i in enumerate(row)]
- rows = sorted(indexed, key=operator.itemgetter(0))
self.m, self.n = self.n, self.m
-
- self.rows = [[] for x in range(self.m)]
-
- for key, val in rows:
- self.rows[key].append(val)
+ self.rows = [list(item) for item in zip(*self.rows)]
def getTranspose(self):
""" Return a transpose of the matrix without
modifying the matrix itself """
- indexed = [i for row in self.rows for i in enumerate(row)]
- rows = sorted(indexed, key=operator.itemgetter(0))
m, n = self.n, self.m
mat = Matrix(m, n)
-
- mat.reset()
-
- for key, val in rows:
- mat.rows[key].append(val)
-
+ mat.rows = [list(item) for item in zip(*self.rows)]
+
return mat
def getRank(self):
@@ -158,6 +148,9 @@
self.m, self.n = tempmat.getRank()
return self
+ def save(self, filename):
+ open(filename, 'w').write(str(self))
+
@classmethod
def _makeMatrix(cls, rows):
@@ -166,7 +159,7 @@
# Validity check
if any([len(row) != n for row in rows[1:]]):
raise MatrixError, "inconsistent row length"
- mat = Matrix(m,n)
+ mat = Matrix(m,n, init=False)
mat.rows = rows
return mat
@@ -175,10 +168,9 @@
def makeRandom(cls, m, n, low=0, high=10):
""" Make a random matrix with elements in range (low-high) """
- obj = Matrix(m, n)
+ obj = Matrix(m, n, init=False)
for x in range(m):
- for y in range(n):
- obj[x][y] = random.randrange(low, high)
+ obj.rows.append([random.randrange(low, high) for i in range(obj.n)])
return obj
@@ -188,7 +180,20 @@
rows = [[0]*n for x in range(m)]
return cls.fromList(rows)
-
+
+ @classmethod
+ def makeId(cls, m):
+ """ Make identity matrix of rank (mxm) """
+
+ rows = [[0]*m for x in range(m)]
+ idx = 0
+
+ for row in rows:
+ row[idx] = 1
+ idx += 1
+
+ return cls.fromList(rows)
+
@classmethod
def readStdin(cls):
""" Read a matrix from standard input """
@@ -264,7 +269,13 @@
m2.transpose()
self.assertTrue(m2 == m1)
-
+
+ def testId(self):
+
+ m1 = Matrix.makeId(10)
+ m2 = Matrix.makeRandom(4, 10)
+ m3 = m2*m1
+ self.assertTrue(m3 == m2)
if __name__ == "__main__":
unittest.main()
