A matrix has the following attributes.
size
A tuple with the dimensions of the matrix. This is a read-only attribute; operations that change the size of a matrix are not permitted.
typecode
A char, either ’i’, ’d’, or ’z’, for integer, real and complex matrices, respectively. A read-only attribute.
trans()
Returns the transpose of the matrix as a new matrix. One can also use A.T instead of A.trans().
ctrans()
Returns the conjugate transpose of the matrix as a new matrix. One can also use A.H instead of A.ctrans().
real()
For complex matrices, returns the real part as a real matrix. For integer and real matrices, returns a copy of the matrix.
imag()
For complex matrices, returns the imaginary part as a real matrix. For integer and real matrices, returns an integer or real zero matrix.
__array_struct__
A PyCObject implementing the NumPy array interface (see section 2.8 for details).
tofile(f)
Writes the elements of the matrix in column-major order to a binary file f.
fromfile(f)
Reads the contents of a binary file f into the matrix object.
The last two methods are illustrated in the following example.
>>> from cvxopt.base import matrix
>>> A = matrix([[1.,2.,3.], [4.,5.,6.]]) >>> print A [ 1.00e+00 4.00e+00] [ 2.00e+00 5.00e+00] [ 3.00e+00 6.00e+00] >>> f = open(’mat.bin’,’w’) >>> A.tofile(f) >>> f.close() >>> B = matrix(0.0, (2,3)) >>> f = open(’mat.bin’,’r’) >>> B.fromfile(f) >>> f.close() >>> print B [ 1.00e+00 3.00e+00 5.00e+00] [ 2.00e+00 4.00e+00 6.00e+00] |
Matrices can also be written to or read from files using the dump() and load() functions in the pickle module.