diff -r d939bf5b1d4e bin/PetscBinaryRead.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/bin/PetscBinaryRead.py	Thu Jul 14 13:18:15 2011 -0600
@@ -0,0 +1,150 @@
+import numpy as np
+import types
+
+IntType    = '>i4'   # big-endian, 4 byte integer
+ScalarType = '>f8'   # big-endian, 8 byte real floating
+_classid = {1211216:'Mat',
+            1211214:'Vec',
+            1211218:'IS',
+            1211219:'Bag'}
+
+class DoneWithFile(Exception): pass
+
+def readVec(fh):
+    """Reads a PETSc Vec from a binary file handle, returning just the data."""
+
+    nz = np.fromfile(fh, dtype=IntType, count=1)[0]
+    try:
+        vals = np.fromfile(fh, dtype=ScalarType, count=nz)
+    except MemoryError:
+        raise IOError('Inconsistent or invalid Vec data in file')
+    return vals
+
+def readMatSparse(fh):
+    """Reads a PETSc Mat, returning a sparse representation of the data.
+
+    (M,N), (I,J,V) = readMatSparse(fid)
+
+    Input:
+      fid : file handle to open binary file.
+    Output:
+      M,N : matrix size
+      I,J : arrays of row and column for each nonzero
+      V: nonzero value
+    """
+    try:
+        M,N,nz = np.fromfile(fh, dtype=IntType, count=3)
+        #
+        I = np.empty(M+1, dtype=IntType)
+        I[0] = 0
+        rownz = np.fromfile(fh, dtype=IntType, count=M)
+        np.cumsum(rownz, out=I[1:])
+        assert I[-1] == nz
+        #
+        J = np.fromfile(fh, dtype=IntType,    count=nz)
+        V = np.fromfile(fh, dtype=ScalarType, count=nz)
+    except AssertionError, MemoryError:
+        raise IOError('Inconsistent or invalid Mat data in file')
+    #
+    return (M, N), (I, J, V)
+
+def readMatDense(fh):
+    """Reads a PETSc Mat, returning a dense represention of the data."""
+    try:
+        M,N,nz = np.fromfile(fh, dtype=IntType, count=3)
+        #
+        I = np.empty(M+1, dtype=IntType)
+        I[0] = 0
+        rownz = np.fromfile(fh, dtype=IntType, count=M)
+        np.cumsum(rownz, out=I[1:])
+        assert I[-1] == nz
+        #
+        J = np.fromfile(fh, dtype=IntType,    count=nz)
+        V = np.fromfile(fh, dtype=ScalarType, count=nz)
+        mat = np.zeros((M,N), dtype=ScalarType)
+        for i,j,v in zip(I,J,V):
+            mat[i,j] = v
+    except AssertionError, MemoryError:
+        raise IOError('Inconsistent or invalid Mat data in file')
+    #
+    return mat
+
+def readMat(fh, mattype='sparse'):
+    """Reads a PETSc Mat from binary file handle.
+
+    optional mattype: 'sparse" or 'dense'
+
+    See also: readMatSparse, readMatDense
+    """
+    if mattype == 'sparse':
+        return readMatSparse(fh)
+    elif mattype == 'dense':
+        return readMatDense(fh)
+    else:
+        raise RuntimeError('Invalid matrix type requested: choose sparse/dense')
+
+def readIS(fh):
+    """Reads a PETSc Index Set from binary file handle."""
+    try:
+        nz = np.fromfile(fh, dtype=IntType, count=1)[0]
+        v = np.fromfile(fh, dtype=IntType, count=nz)
+    except MemoryError:
+        raise IOError('Inconsistent or invalid IS data in file')
+    return v
+
+def readBinaryFile(fid, mattype='sparse'):
+    """Reads a PETSc binary file, returning a tuple of objects contained in the file.
+
+    objects = readBinaryFile(fid, mattype='sparse')
+
+    Input:
+      fid : either file handle to open binary file, or filename
+      mattype : ['sparse'] Read matrices as 'sparse' (row, col, val) or 'dense'.
+
+    Output:
+      objects : tuple of objects representing the data.
+    """
+    close = False
+
+    if type(fid) is types.StringType:
+        fid = open(fid, 'rb')
+        close = True
+
+    objects = []
+    try:
+        while True:
+            # read header
+            try:
+                header = np.fromfile(fid, dtype=IntType, count=1)[0]
+            except MemoryError:
+                raise DoneWithFile
+            try:
+                objecttype = _classid[header]
+            except KeyError:
+                raise IOError('Invalid PetscObject CLASSID or CLASSID not yet implemented')
+
+            if objecttype == 'Vec':
+                objects.append(('Vec', readVec(fid)))
+            elif objecttype == 'IS':
+                objects.append(('IS', readIS(fid)))
+            elif objecttype == 'Mat':
+                objects.append(('Mat', readMat(fid,mattype)))
+            elif objecttype == 'Bag':
+                raise NotImplementedError('Bag Reader not yet implemented')
+    except DoneWithFile:
+        pass
+    finally:
+        if close:
+            fid.close()
+    #
+    return tuple(objects)
+
+if __name__ == '__main__':
+    import sys
+    objects = readBinaryFile(sys.argv[1])
+    for otype, data in objects:
+        print 'Read a', otype
+        print data
+        print '\n'
+
+