above are the question to write a MATLAB code without using spline function. thi
ID: 3736536 • Letter: A
Question
above are the question to write a MATLAB code without using spline function. this photo below shows how the f matrices should look like after writing n, n-1 , n-2 equations. before finding the P and B matrices we need F matrices. can you also send the pics of failed plots too.
Explanation / Answer
Given that,
Assume you are given a set of independent (X) and dependent (Y) data points and you want to interpolate the values of the data between the given points.
X = IXt, x2, x3, x41 Y = [Y1, Yz, Y3, Y41
For this data, the length is n = 4 you will need n-, 3 estimation functions (1 between each set of data points)
For cubic spline interpolation, these estimation functions look like
: S1, = a1x3 + b1x2 + cix + di for xi 5 x 5 X,
S2 = a2x3 + b2x2 + c2x + c12 for x2 < x < x,
S3 = a3x3 + b3x2 + c3x + d3 for x3 < x < x4
Program:-
x = [0 1 2.5 3.6 5 7 8.1 10];
y = sin(x);
xx = 0:.25:10;
yy = spline(x,y,xx);
plot(x,y,"o",xx,yy)
x = -4:4;
y = [0 .15 1.12 2.36 2.36 1.46 .49 .06 0];
cs = spline (x,[0 uy 0]);
xx = linspace(-4,4,101);
plot(x,y,"o',xx,ppval(cs,xx).'-');
t = 1900:10:1990;
p = [75.995 91.972 105.711 123.203 131.669 .....
150.697 179.323 203.212 226.505 249.633];
spline(t,p,2000)
x = pi*[0:.5:2];
y = [0 1 0 - 1 0 1 0;
1 0 1 0 - 1 0 1];
pp = spline(x,y);
yy = ppval(pp, linspace(0,2*pi,101));
plot(yy(1,:), yy(2,:),'-b',y(1,2:5),y(2,2:5),'or')
axis equal
x = 0:.25:1;
Y = [sin(X); cos(X)];
xx = 0:.1:1;
YY = spline(x,Y,xx);
plot(x,Y(1,:),'o',xx,YY(1,:),'-')
hold on
plot(x,Y(2,:),'o',xx,YY(2,:),':')
hold off
x = 0:25;
y = besselj(1,x);
xq2 = 0:0.01:25;
p = pchip(x,y,xq2);
s = spline(x,y,xq2);
plot(x,y,'o',xq2,p,'-',xq2,s,'-'.)
legend('Sample Points,"pchip",spline')
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