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TableFunction.m
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TableFunction.m
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classdef TableFunction
properties
data (:,2) double
end
methods
function obj = TableFunction(data)
obj.data = data;
end
function out = func(obj,arg)
out = interp1(obj.data(:,1), obj.data(:,2), arg, "linear",'extrap');
end
function out = inv(obj,arg)
out = interp1(obj.data(:,2), obj.data(:,1), arg, "linear",'extrap');
end
function out = deriv(obj,arg)
out = compute_derivative(obj.data(:,1), obj.data(:,2), arg);
end
end
end
function df = compute_derivative(x, f, x0)
% x: vector of x values
% f: vector of f(x) values
% x0: point at which to compute the derivative
% Find the index of the closest point to x0
[~, idx] = min(abs(x - x0));
% Check if we can use central difference
if idx > 1 && idx < length(x)
% Central difference formula
h = x(idx+1) - x(idx-1);
df = (f(idx+1) - f(idx-1)) / h;
elseif idx == 1
% Forward difference formula
h = x(2) - x(1);
df = (f(2) - f(1)) / h;
else
% Backward difference formula
h = x(end) - x(end-1);
df = (f(end) - f(end-1)) / h;
end
end