第2周--Basic Operations
>> 1 && 0
ans = 0
>> 1 || 0
ans = 1
>> xor(1,0)
ans = 1
>> PS('>> ');
error: 'PS' undefined near line 1 column 1
>> PS1('>> '); %PS1() is a function that is used for Query or set the primary prompt string.
>> PS1('>> ')
>> T = PS1('>>')
T = >>
>>clear
>>a = 3
a = 3
>>b = 'hi';
>>b
b = hi
>>c = (3>=1);
>>c
c = 1
>>a = pi;
>>a
a = 3.1416
>>disp(a);
3.1416
>>disp(sprintf('2 decimals: %0.2f',a)) %Here to control its bits after the point are 2
2 decimals: 3.14
>>disp(sprintf('6 decimals: %0.6f',a)) %Here to control its bits after the point are 6
6 decimals: 3.141593
>>format long
>>a
a = 3.141592653589793
>>format short
>>a
a = 3.1416接下来这部分是基本的一些矩阵相关
>>A = [1 2; 3 4; 5 6]
A =
1 2
3 4
5 6
>>A = [1 2;]
A =
1 2
>>A = [1 2;
3 4;
5 6]
A =
1 2
3 4
5 6
>>
>>V = [1 2 3]
V =
1 2 3
>>V = [1; 2; 3]
V =
1
2
3
>>V = 1:0.1:2
V =
Columns 1 through 9:
1.0000 1.1000 1.2000 1.3000 1.4000 1.5000 1.6000 1.7000 1.8000
Columns 10 and 11:
1.9000 2.0000
>>V = 1:6
V =
1 2 3 4 5 6
>>
>>
>>ones(2,3)
ans =
1 1 1
1 1 1
>>C = 2 * ones(2,3)
C =
2 2 2
2 2 2
>>c = [2 2 2; 2 2 2]
c =
2 2 2
2 2 2
>>W = ones(1,3)
W =
1 1 1
>>w = zeros(1,3)
w =
0 0 0
>>w = rand(1,3)
w =
0.56964 0.58711 0.16050
>>rand(3,3)
ans =
0.31862 0.17487 0.89735
0.33011 0.81878 0.42345
0.61995 0.61151 0.66674
>>
>>rand(3,3)
ans =
0.55248 0.41297 0.69621
0.76598 0.86068 0.19670
0.18062 0.59087 0.85608
>>w = randn(1,3)
w =
-0.55813 -0.16527 -1.17928
>>
>>
>>
>>w = -6 + sqrt(10) * (randn(1,10000));
>>>w = -6 + sqrt(10) * (randn(1,10000))
parse error:
syntax error
>>> >w = -6 + sqrt(10) * (randn(1,10000))
^
>>hist(w)
>>hist(w)
>>hist(w,50)
>>
>>
>>eye(4)
ans =
Diagonal Matrix
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
>>I = eye(4)
I =
Diagonal Matrix
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
>>I = eye(6)
I =
Diagonal Matrix
1 0 0 0 0 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 1 0 0
0 0 0 0 1 0
0 0 0 0 0 1
>>
>>
>>help
For help with individual commands and functions type
help NAME
(replace NAME with the name of the command or function you would
like to learn more about; for an operator, enclose "NAME" in quotes).
For a more detailed introduction to GNU Octave, consult the manual.
The manual may be read from the prompt by typing
doc
GNU Octave is supported and developed by its user community.
For more information visit https://www.octave.org.
>>help eye
'eye' is a built-in function from the file libinterp/corefcn/data.cc
-- eye (N)
-- eye (M, N)
-- eye ([M N])
-- eye (..., CLASS)
Return an identity matrix.
If invoked with a single scalar argument N, return a square NxN
identity matrix.
If supplied two scalar arguments (M, N), 'eye' takes them to be the
number of rows and columns. If given a vector with two elements,
'eye' uses the values of the elements as the number of rows and
columns, respectively. For example:
eye (3)
=> 1 0 0
0 1 0
0 0 1
The following expressions all produce the same result:
eye (2)
==
eye (2, 2)
==
eye (size ([1, 2; 3, 4]))
The optional argument CLASS, allows 'eye' to return an array of the
specified type, like
val = zeros (n,m, "uint8")
Calling 'eye' with no arguments is equivalent to calling it with an
argument of 1. Any negative dimensions are treated as zero. These
odd definitions are for compatibility with MATLAB.
See also: speye, ones, zeros.
Additional help for built-in functions and operators is
available in the online version of the manual. Use the command
'doc <topic>' to search the manual index.
Help and information about Octave is also available on the WWW
at https://www.octave.org and via the [email protected]
mailing list.