- •Міністерство освіти і науки, молоді та спорту україни
- •Laboratory Works of Computing and Programming
- •Contents
- •1.2 Base Concepts of Operating Systems
- •1.3 Linux (lubuntu) Operating System
- •1.4 Tasks for Independent Work
- •1.5 Test Questions
- •2 Laboratory work № 2 Word Processor libreoffice.Writer
- •2.1 What Word Processors Can Do
- •2.2 Tasks for Independent Work
- •2.3 Test Questions
- •3 Laboratory work № 3
- •Introduction to the calc spreadsheet
- •3.1 The Basic Opportunities of Spreadsheets
- •3.1.1 Calc’s Environment
- •3.1.2 Calculations in Calc. Creating and Coping Formulas
- •3.2 The Calc charting capability
- •3.3 Tasks for Independent Work
- •4.2 Main Rules of Works in Scilab System
- •Variables
- •Input of vectors (arrays)
- •Input of matrixes
- •Some operations with matrixes with use of the operator ":"
- •Input from keyboard
- •Operators. Expressions use familiar arithmetic operators and precedence rules.
- •Intrinsic scilab Functions
- •Examples of Expressions
- •4.3 Individual Tasks for Laboratory Work
- •4.4 The Tasks for Self-Examination
- •4.5 Test Questions
- •5 Laboratory work № 5
- •5.3.1The plot function
- •5.3.3 Preparing Graphs for Presentation
- •Interactive Plot Editing
- •5.3.4 3D Plotting
- •5.4 Individual Tasks
- •5.6 Test Questions
- •6 Laboratory work № 6 programming in Scilab
- •6.1 Programming in scilab
- •What Happens When You Call a Function
- •Clearing Functions from Memory
- •6.2 Tasks for laboratory work
- •6.3 Example of performance of the laboratory work
- •6.4 Test Questions
- •7 ReferencEs
Input of vectors (arrays)
Row vectors can be declared using brackets:
>> row_v = [0 1 2]
row_v =0 1 2
To declare column vectors, we use semi-colon at the end of each line:
>> col_v = [0;1;2]
col_v =0
1
2
It is also possible to transpose vectors using the apostrophe (asterisk):
>> col_v = row_v’
col_v =0
1
2
>> row_v = col_v’
row_v = 0 1 2
The colon (:) command easily built the vector. To build an array x of x-values starting at x = 0, ending at x = 1, and having a step size of h =0.1 type this:
>> x=0:0.1:1
The colon is the incremental operator in SCILAB (with default value set to 1):
>> row_v2 = [0:5] // using default increment
row_v2 = 0 1 2 3 4 5
>> row_v3 = [0:0.2:1] // using a different increment
row_v3 = 0.2000 0.4000 0.6000 0.8000 1.0000
Row vectors can be declared using function
linspace(start_value,end_value,amount_of_values)
-->linspace(1,5,9)
ans = 1.000 1.500 2.000 2.500 3.000 3.500 4.0000 4.5000 5.0000
Input of matrixes
A(i, j) - an element i-line and j-column.
A(k) - k-element of the table extended in a column.
Indexes (i, j) always begin with 1.
Matrices are defined by entering the elements row by row. Command
>>M = [1 2 4; 3 6 8];
creates the matrix M = [1 2 4
3 6 8].
There are a number of special matrices that can be defined:
null matrix: M = [];
n-by-m matrix of zeros: M = zeros(n,m);
n-by-m matrix of ones: M = ones(n,m);
n-by-n identity matrix: M = eye(n).
Examples:
A particular element of a matrix can be assigned:
--> M(1,2) = 5;
places the number 5 in the first row, second column.
The colon by itself refers to all the elements of the j-th column of A.
--> b=M(1,:)
b=1 2 4
Some operations with matrixes with use of the operator ":"
А(:, j) |
refers to all the elements of the j-th column of A |
А(:, j:k) |
refers to the all elements from j to k columns of А |
А(і,:) |
refers to all the elements from i-row of matrix A |
А(i:k,:) |
refers to the all elements from i to k rows of matrix A |
А(:) |
refers to all the elements of a matrix A |
Function size returns Size of array.
The function length() is related to size(). For a matrix with numeric elements length() returns the number of elements.
Concatenation is the process of joining small matrices to make bigger ones. In fact, even the simplest matrix is formed by concatenating its individual elements. The pair of square brackets, [], is the concatenation operator. In this example a 4x4 matrix has been created by concatenating four 2x2 matrices.
|
|
Input from keyboard
To have a script request and assign a value to the variable N from the keyboard use
N=input(“ Enter a value for N - “)
You can enter only a single number, like 2.7, then N will be a scalar variable. The load function reads binary files containing matrices generated by earlier SCILAB sessions.
Execute the following commands:
A=[1,2;3,4] A=[1;2,3;4] А(2,2) А(3) А(5) size(A)
А(3,4)=10 size(A) А(5)=6 size(A) А(22)=3 A=A(:) А(22)=3
size(A) [m,n]=size(A)
A=reshape(1:24,4,6) size(A)
А([1,end],:)=[ ] А(:,[1,end])=[ ] size(A)