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LinlyBoi
2023-05-14 22:18:10 +03:00
parent 140ff50583
commit eecdd1537c
1 changed files with 9 additions and 7 deletions
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16
newton_differentiation.m
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@@ -1,4 +1,5 @@
Y = [] %it doesn't like when I don't add this Y = [] %it doesn't like when I don't add this
% ze basic functions for differentiating
function y = f_newt_diff1(Y,h) function y = f_newt_diff1(Y,h)
y = ( Y(2) - Y(1) ) / h y = ( Y(2) - Y(1) ) / h
end end
@@ -12,17 +13,18 @@ function y = b_newt_diff1(Y,h)
y = ( Y(1) - Y(2) ) / h y = ( Y(1) - Y(2) ) / h
end end
% this one retrieves elements from "table" and decides which one to usejava
% uses Centered when possible
function y = newt_diff_fr1(Y,X,x,h) function y = newt_diff_fr1(Y,X,x,h)
idx = find(X==x); idx = find(X==x);
if (idx == length(X)) if (idx == length(X)) %backwards
elems = [Y(idx), Y(idx-1)] elems = [Y(idx), Y(idx-1)]
y = b_newt_diff1(elems,h) y = b_newt_diff1(elems,h)
elseif (idx == 1) elseif (idx == 1) %forwards
elems = [Y(idx), Y(idx+1)] elems = [Y(idx), Y(idx+1)]
y = f_newt_diff1(elems,h) y = f_newt_diff1(elems,h)
else else %centered
elems = [Y(idx-1), Y(idx+1)] elems = [Y(idx-1), Y(idx+1)]
y = c_newt_diff1(elems,h) y = c_newt_diff1(elems,h)
endif endif
@@ -41,7 +43,7 @@ newt_diff_fr1(Y,X,1,1)
% functions but...level 2!
function y = f_newt_diff2(Y,h) function y = f_newt_diff2(Y,h)
y = ( Y(3) - 2 * Y(2) + Y(1) ) / h^2 y = ( Y(3) - 2 * Y(2) + Y(1) ) / h^2
end end
@@ -58,8 +60,8 @@ end
%Defaults to center level 2
function y = newt_diff_fr2(Y,X,x,h) function y = newt_diff_fr2(Y,X,x,h) %Y -> f(x), X -> x, x -> value we want, h..
idx = find(X==x); idx = find(X==x);
if (idx == length(X)) %forwards if (idx == length(X)) %forwards
elems = [Y(idx), Y(idx-1), Y(idx-2)] elems = [Y(idx), Y(idx-1), Y(idx-2)]