Undan tashqari matlabda maxsus ko’rinishdagi matritsalarni hosil qilish imkoniyati
bor. Ana shunday matritsalarni hosil qiluvchi komandalarni kyeltirib o’tamiz:
-
size (A) – A matritsaning o’lchovi;
-
length (A) –A vyektor uzunligi (elyemyentlar soni);
-
ndims (A) – A matritsa o’lchovlari soni;
-
isempty (A) – A matritsa bo’sh bo’lsa 1, aks holda 0 qiymatni byeradi;
-
isegual (A, V) – A=V bo’lsa 1
ni byeradi, aks xolda “0” ni byeradi;
inumeric (A) – A matritsa sonli tipda bo’lsa 1 ni byeradi, aks holda “0” ni byeradi;
Namunalar:
1 – misol: Berilgan A va B matritsalarni bir biriga ko’paytirish:
>> A=[-1 0 1; 0 -1 0; 1 -1 1]
A =
-1 0 1
0 -1 0
1 -1 1
>> B=[1 1 0; 2 -1 0; 3 0 1]
B =
-1 1 0
2 -1 0
3 0 1
>> A*B ans
=
2 -1 1
-2 1 0
2 2 1
Endi shu amalni algoritmi haqida ya’ni o’z qo’limiz yordamida bajaramiz:
>> for i=1:3; for j=1:3; C(i,j)=0; for k=1:3; C(i,j)=C(i,j)+A(i,k)*B(k,j); end; end; end;
C C =
2 -1 1
-2 1 0
2 2 1
2-Misol: A va B matritsalarni bir-biriga qo’shish
>> A=[-1 0 1; 0 -1 0; 1 -1 1];
>> B=[1 1 0; 2 -1 0; 3 0 1];
>> A+B ans
=
0 1 1
2 -2 0
C =
1 0 -1
0
-1 0
1
-1 1
5 – misol: Berilgan matritsani soat strelkasiga qarshi 90
0
ga
burish uchun
ishlatiladigan rot90(A) komandasi:
>> A=[-1 0 1; 0 -1 0; 1 -1 1]
A =
-1 0 1
0 -1 0
1 -1 1
>> rot90(A) ans =
1 0 1
0 -1 -1 -
1 0 1
Endi shu amalning bajarilish tartibi ya’ni algoritmi haqida:
>> for i=1:3; for j=1:3; C(i,j)=A(j,3-i+1); end; end; C
C =
1 0 1
0
-1 -1
1
0 1
Undan tashqari matlabda maxsus ko’rinishdagi matritsalarni hosil qilish imkoniyati
bor. Ana shunday matritsalarni hosil qiluvchi komandalarni kyeltirib o’tamiz:
>> A=[-1 0 1; 0 -1 0; 1 -1 1]
A =
-1 0 1
0 -1 0
1 -1 1
>> size(A) ans
=
3 3
>> length(A)
ans = 3
>> ndims(A)
ans =
2
>> isempty(A) ans =
0
6 - misol: diag(A) komandasi berilgan matritsaning diagonalida tugan elementlarni
ekranga chiqaradi:
>> A=[-1 0 1; 0 -1 0; 1 -1 1]
A =
-1 0 1
0 -1 0
1 -1 1
>> diag(A) ans =
-1 -1 1
Shu amalni o’zimiz bajarib chqamiz:
>> for i=1:3; D(i)=A(i,i);end; D
D =
-1 -1 1
7 – misol: eye(n) komandasi birlik matritsa hosil qilish:
>> eye(5) ans =
1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 1 0
0 0 0 0 1
Endi shu matritsani m-faylga funksiyasini yaratamiz:
Ushbu m-faylga birlik matritsa hosil qiladigan protsedura
yasadik va uning nomini
diagonal.m deb nomladik. Endi bu m-fayl yordamida diagonal(n) komandasi hosil
bo’ldi. Endi ushbu komanda yordamida ham eye(n) komandasining bajargan ishini
bajarsa bo’ladi: >> diagonal(5) ans =
1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 1 0
0 0 0 0 1
8-misol: Berilgan matritsaning diagonaildan yuqori qismini elementlarini 0
bilan
almashtirish:
>> A=[-1 2 4 0 3; -2 1 0 3 4; -2 -1 0 -2 1; -2 3 -1 -1 1; 1 1 1 -1 -1]
A =
-1 2 4 0 3
-2 1 0 3 4
-2 -1 0 -2 1
-2 3 -1 -1 1
1 1 1 -1 -1
>> tril(A) ans
=
-1 0 0 0 0
-2 1 0 0 0
-2 -1 0 0 0
-2 3 -1 -1 0
1 1 1 -1 -1
Endi shu komandani o’zimiz m-faylga yozib yangi yuqori degan komanda hosil
qilamiz :
0 0 0 -1 1
0 0 0 0 -1
10 – misol :
RESHAPE – matrisa o’lchamini o’zgartish :
>> A=[-1 0 2 0; 0 1 2 -1; -1 -2 -3 2]
A =
-1 0 2 0
0 1 2 -1
-1 -2 -3 2
>> reshape(A,2,6) ans =
-1 -1 1 2 -3 -1
0 0 -2 2 0 2
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