MATLAB Answers

Changing composition of Row Matrix (1x9) into a 3x3 Matrix

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Anilcan Taner
Anilcan Taner on 27 Oct 2019
Commented: Daniel M on 27 Oct 2019
Im a newbie matlab student who has a project for solving a hydraulic problem with finite element method in Matlab.
So far seems good, but I am having difficult time since I have no background about algorithm and programming.
My problem here is;
1-) Making K{i} into a K1 K2 K3 [ seems not necessary if im not wrong but it would make me feel much safer :) ],
2-) K{1} to K{9} looks like something like this,
[1 2 3 4 5 6 7 8 9]
and I need them to look like
[1 2 3; 4 5 6; 7 8 9]
Yes, I am an idiot.
Sorry for Turkish explanations.
echo off all
clc
nodeX = [0,5,9.17,12,0,5,9.17,12,0,5,8,9.17,12]; % noktalarin x koordinatlari
nodeY = [8,8,8,8,4,4,5.5,5.5,0,0,0,2.83,4]; % noktalarin y koordinatlari
elemX = [5,6,6,7,7,7,5,9,10,11,6,7,7]; % i icin olusan ucgenlerin global nokta karsiliklari
elemY = [1,1,2,2,3,4,6,6,6,6,7,12,8]; % j icin
elemZ = [6,2,7,3,4,8,9,10,11,12,12,13,13]; % k icin
varTable = [];
fprintf("e xi\txj\txk\tyi\tyj\tyk\tck\tci\tcj\tbi\tbj\tbk\tA\n"); % tablo basligini formatla
for i = 1:length(elemX)
% sirasiyla elemanlari okutuyoruz
currElemX = elemX(i);
currElemY = elemY(i);
currElemZ = elemZ(i);
% i ye karsilik gelen global noktalarin koordinat karsiliklari
% bulunuyor
xi = nodeX(elemX(i));
xj = nodeX(elemY(i));
xk = nodeX(elemZ(i));
yi = nodeY(elemX(i));
yj = nodeY(elemY(i));
yk = nodeY(elemZ(i));
% gerekli hesaplama yapiliyor
ck = xj - xi;
ci = xk - xj;
cj = xi - xk;
bi = yj - yk;
bj = yk - yi;
bk = yi - yj;
% alan hesabi
A = abs(0.5 * (xi * yj + xj * yk + xk * yi - xi * yk - xj * yi - xk * yj));
%dongunun disinda kullanmak icin bulunan degerleri sakla
varTable = [varTable ; ck,ci,cj,bi,bj,bk,A];
% ekrana uygun formatla yazdiriliyor
fprintf("%d %.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.2f\t%.4f\t\n",i,xi,xj,xk,yi,yj,yk,ck,ci,cj,bi,bj,bk,A);
end
Kcal= array2table(varTable, 'Variablenames',{'ck','ci','cj','bi','bj','bk','A'}) %K 3x3 matris hesabi icin tablo
%tablodaki degerleri disari cekiyorum sutunlari ayri olarak
%A='Tablename'.'variablename' komutu ile
%n sembolu sondaki sadece karisiklik onlemek amacli
cint=Kcal.ci;
cjnt=Kcal.cj;
cknt=Kcal.ck;
bint=Kcal.bi;
bjnt=Kcal.bj;
bknt=Kcal.bk;
Ant=Kcal.A;
%Transpoze ediyoruz satira cevirmek icin sutun matrisini
bin=bint.';
bjn=bjnt.';
bkn=bknt.';
cin=cint.';
cjn=cjnt.';
ckn=cknt.';
An=Ant.';
%Yazdiracagimiz icin basliklar \t ile tab bosluk biraktirliyor \n ile yeni
%satir yazdiriliyor.
fprintf("e K11\tK12\tK13\tK21\tK22\tK23\tK31\tK32\tK33\n"); % tablo basligini formatla
%Degiskenler icin bos matris
varTable2 = [];
for i=1:height(Kcal) % Kcal sutun olarak dizildigi icin height kullandik.
currcin=cin(i);
currcjn=cjn(i);
currckn=ckn(i);
currbin=bin(i);
currbjn=bjn(i);
currbkn=bkn(i);
currAn=An(i);
cinn=cin(i);
cjnn=cjn(i);
cknn=ckn(i);
binn=bin(i);
bjnn=bjn(i);
bknn=bkn(i);
Ann=An(i);
% K Row x Column olarak isimlendirir isek, 3x3 matrisin degerleri
K11=(1/(4 * Ann)) * ( binn^2 + cinn^2);
K12=(1/(4 * Ann)) * ((binn * bjnn) + (cinn * cjnn));
K13=(1/(4 * Ann)) * ((binn * bknn) + (cinn * cknn));
K21=(1/(4 * Ann)) * ((binn * bjnn) + (cinn * cjnn));
K22=(1/(4 * Ann)) * ((bjnn)^2 + (cjnn)^2);
K23=(1/(4 * Ann)) * ((bjnn * bknn) + (cjnn * cknn));
K31=(1/(4 * Ann)) * ((binn * bknn) + (cinn * cknn));
K32=(1/(4 * Ann)) * ((bjnn * bknn) + (cjnn * cknn));
K33=(1/(4 * Ann)) * ((bknn)^2 + (cknn)^2);
varTable2 = [varTable2 ; K11, K12,K13, K21, K22, K23, K31, K32, K33]; %Degiskenleri tabloya aliyoruz
%%%%%%%%%%%%%%%%% YAZDIRMADA SIKINTI VAR %%%%%%%%%%%%%%%
fprintf("%d %.4f\t%.4f\t%.4f\t%.4f\t%.4f\t%.4f\t%.4f\t%.4f\t%.4f\t%.4f\t\n",i,K11,K12,K13,K21,K22,K23,K31,K32,K33);
%%%%%%%%%%%%%%%%% YAZDIRMADA SIKINTI VAR %%%%%%%%%%%%%%%
end
Kcal2= array2table(varTable2, 'Variablenames',{'K11','K12','K13','K21','K22','K23','K31', 'K32', 'K33'}) %K 3x3 matris hesabi icin tablo2
%K matrislerini olusturmak icin verilerimiz hazir.
%Siradaki islem bu verileri 3x3 Matrislere yerlestirmek.
% 1.SIRA: K1 K2 K3 VERILERINI AYRI AYRI CEKMEK
%%%%%%%%%%%%%%%%%% BURADA KOPUYORUM %%%%%%%%%%%%%%%%%%%%%%
varTable3 = [];
for i=1:height(Kcal2)
varK = [1:1:i]; %1 den i ye kadar rakamlardan olusan satir matrisi yazdirdik
K{i}=varTable2(i,:); %3x3 matrisleri K{1} K{2} olarak ayirir row matrisi olarak
end
K1=K{1}

Accepted Answer

Anilcan Taner
Anilcan Taner on 27 Oct 2019
Problem is solve with the help of reshape function,
However, problem never ends in a newbie world.
with the code of;
K{i}=varTable2(i,:);
I created K1 K2 K3 in cell form but i want them in a double form indeed.
So that's my second question.

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