# 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)

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()

x.__init__(...) initializes x; see help(type(x)) for signature

get(var)

Get the value of the variable var.

EXAMPLES:

sage: s = matlab.eval('a = 2') # optional - matlab
sage: matlab.get('a')               #optional
'     2'

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)   # 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.

Returns the string s with Matlab’s answer prompt removed.

EXAMPLES:

sage: s = '\nans =\n\n     2\n'
'     2'

version()

x.__init__(...) initializes x; see help(type(x)) for signature

whos()

x.__init__(...) initializes x; see help(type(x)) for signature

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

x.__init__(...) initializes x; see help(type(x)) for signature

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; not tested
< M A T L A B >
...
>> 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
'7.2.0.283 (R2006a)'


x.__init__(...) initializes x; see help(type(x)) for signature