Hermite cubic interpolating polynomial with specified derivatives: test2.m - File Exchange

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Hermite cubic interpolating polynomial with specified derivatives

pchipd(x,y,d,xx) PCHIPD Piecewise Cubic Hermite Interpolating Polynomial with Derivatives.
test1.m
test2.m
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from Hermite cubic interpolating polynomial with specified derivatives by Nick Henderson
Computes piecewise cubic polynomial which interpolates function values and first derivatives.

test2.m

a = -10;
b = 10;
x = linspace(a,b,7); 
f = @(x) 1./(1+exp(-x));
df = @(x) f(x).*(1-f(x));
t = linspace(a,b,50);
r = f(t);
p = pchip(x,f(x),t);
s = spline(x,f(x),t);
q = pchipd(x,f(x),df(x),t);
plot(t,r,'k',x,f(x),'o',t,p,'-',t,s,'-.',t,q,'--')
legend('true','data','pchip','spline','pchipd',4)

Highlights from Hermite cubic interpolating polynomial with specified derivatives

Highlights from
Hermite cubic interpolating polynomial with specified derivatives