AAA

curve-fittingig.m

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+clear, clc, close all
+#xf = [0:0.05:10];
+#Yf = sin (2*pi*xf/5);
+#xp = [0:10];
+#Yp = sin (2*pi*xp/5);
+#lin = interp1 (xp, Yp, xf);
+#near = interp1 (xp, Yp, xf, "nearest");
+#pch = interp1 (xp, Yp, xf, "pchip");
+#spl = interp1 (xp, Yp, xf, "spline");
+#plot (xf,Yf,"r", xf,near,"g", xf,lin,"b", xf,pch,"c", xf,spl,"m",
+#      xp,Yp,"r*");
+#legend ("original", "nearest", "linear", "pchip", "spline");
+x = [0 4 8 12];
+
+y = [5 3 10 13];
+
+n = length(x);
+
+Y = log(y);
+
+coeff = [sum(x) n; sum(x.^2) sum(x)];
+
+free = [sum(Y); sum(x.*Y)];
+
+V = coeff\free # inv(coeff) * free
+
+A = V(1)
+#exp:
+a = exp(A)
+
+b = V(2)
+
+Sr = (sum(Y - a*x - b).^2)
+
+f = a*x + b;
+
+plot(x,y,'*',x,f)
+