Interface to MATLAB

According to their website, MATLAB is “a high-level language and interactive environment that enables you to perform computationally intensive tasks faster than with traditional programming languages such as C, C++, and Fortran.”

The commands in this section only work if you have the “matlab” interpreter installed and available in your PATH. It’s not necessary to install any special Sage packages.

EXAMPLES:

sage: matlab.eval('2+2')                 # optional
'\nans =\n\n     4\n'

sage: a = matlab(10)                     # optional
sage: a**10                              # optional
   1.0000e+10

AUTHORS:

• William Stein (2006-10-11)

Tutorial

EXAMPLES:

sage: matlab('4+10')                     # optional
14
sage: matlab('date')                    # optional; random output
18-Oct-2006
sage: matlab('5*10 + 6')                 # optional
56
sage: matlab('(6+6)/3')                  # optional
4
sage: matlab('9')^2                      # optional
81
sage: a = matlab(10); b = matlab(20); c = matlab(30)    # optional
sage: avg = (a+b+c)/3                    # optional
sage: avg                                # optional
20
sage: parent(avg)                        # optional
Matlab

sage: my_scalar = matlab('3.1415')       # optional
sage: my_scalar                          # optional
3.1415
sage: my_vector1 = matlab('[1,5,7]')     # optional
sage: my_vector1                         # optional
1     5     7
sage: my_vector2 = matlab('[1;5;7]')     # optional
sage: my_vector2                         # optional
1
5
7
sage: my_vector1 * my_vector2            # optional
75

sage: row_vector1 = matlab('[1 2 3]')             # optional
sage: row_vector2 = matlab('[3 2 1]')             # optional
sage: matrix_from_row_vec = matlab('[%s; %s]'%(row_vector1.name(), row_vector2.name()))     # optional
sage: matrix_from_row_vec                            # optional
1     2     3
3     2     1

sage: column_vector1 = matlab('[1;3]')               # optional
sage: column_vector2 = matlab('[2;8]')               # optional
sage: matrix_from_col_vec = matlab('[%s %s]'%(column_vector1.name(), column_vector2.name()))                                    # optional
sage: matrix_from_col_vec                            # optional
1     2
3     8

sage: my_matrix = matlab('[8, 12, 19; 7, 3, 2; 12, 4, 23; 8, 1, 1]')    # optional
sage: my_matrix                                      # optional
     8    12    19
     7     3     2
    12     4    23
     8     1     1

sage: combined_matrix = matlab('[%s, %s]'%(my_matrix.name(), my_matrix.name()))                                        # optional
sage: combined_matrix                               # optional
 8    12    19     8    12    19
 7     3     2     7     3     2
12     4    23    12     4    23
 8     1     1     8     1     1

sage: tm = matlab('0.5:2:10')                       # optional
sage: tm                                            # optional
0.5000    2.5000    4.5000    6.5000    8.5000

sage: my_vector1 = matlab('[1,5,7]')                # optional
sage: my_vector1(1)                                 # optional
1
sage: my_vector1(2)                                 # optional
5
sage: my_vector1(3)                                 # optional
7

Matrix indexing works as follows:

sage: my_matrix = matlab('[8, 12, 19; 7, 3, 2; 12, 4, 23; 8, 1, 1]')     # optional
sage: my_matrix(3,2)                                # optional
4

Setting using parenthesis cannot work (because of how the Python language works). Use square brackets or the set function:

sage: my_matrix = matlab('[8, 12, 19; 7, 3, 2; 12, 4, 23; 8, 1, 1]')    # optional
sage: my_matrix.set(2,3, 1999)                          # optional
sage: my_matrix                                         # optional
           8          12          19
           7           3        1999
          12           4          23
           8           1           1

class sage.interfaces.matlab.Matlab(maxread=100, script_subdirectory='', logfile=None, server=None, server_tmpdir=None)

Bases: sage.interfaces.expect.Expect

Interface to the Matlab interpreter.

EXAMPLES:

sage: a = matlab('[ 1, 1, 2; 3, 5, 8; 13, 21, 33 ]')    # optional
sage: b = matlab('[ 1; 3; 13]')                         # optional
sage: c = a * b                                         # optional
sage: print c                                           # optional
    30
   122
   505

chdir(directory)

Change MATLAB’s current working directory.

EXAMPLES:

sage: matlab.chdir('/')          # optional - matlab
sage: matlab.pwd()               # optional - matlab
/

console()

get(var)

Get the value of the variable var.

sage2matlab_matrix_string(A)

Return an matlab matrix from a Sage matrix.

INPUT: A Sage matrix with entries in the rationals or reals.

OUTPUT: A string that evaluates to an Matlab matrix.

EXAMPLES:

sage: M33 = MatrixSpace(QQ,3,3)                      
sage: A = M33([1,2,3,4,5,6,7,8,0])
sage: matlab.sage2matlab_matrix_string(A)   # requires optional matlab
'[1, 2, 3; 4, 5, 6; 7, 8, 0]'

AUTHOR:

• David Joyner and William Stein

set(var, value)

Set the variable var to the given value.

version()

whos()

class sage.interfaces.matlab.MatlabElement(parent, value, is_name=False, name=None)

Bases: sage.interfaces.expect.ExpectElement

set(i, j, x)

sage.interfaces.matlab.matlab_console()

This requires that the optional matlab program be installed and in your PATH, but no optional Sage packages need be installed.

EXAMPLES:

sage: matlab_console()                               # optional and not tested
                               < M A T L A B >
                   Copyright 1984-2006 The MathWorks, Inc.
...
>> 2+3

ans =

5

quit

Typing quit exits the matlab console and returns you to Sage. matlab, like Sage, remembers its history from one session to another.

sage.interfaces.matlab.matlab_version()

Return the version of Matlab installed.

EXAMPLES:

sage: matlab_version()    # random optional matlab package
'7.2.0.283 (R2006a)'

sage.interfaces.matlab.reduce_load_Matlab()