divide and conquer

please

anyone can give me source code about divide and conquer method

thank you

[Oleg Komarov]

Being "an algorithm design paradigm" there's no specific source code for it: http://en.wikipedia.org/wiki/Divide_and_conquer_algorithm

Also, additional info could give contributors a chance of answering:

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Daniel Shub]

My guess is this is a sorting question...

Answer 1

[Walter Roberson]

Certainly. In order for this to be a proper "divide and conquer" source contribution, each of the readers of this site will contribute part of the source, and it will be up to you to put everything together.

My contribution to your D&Q source follows on the next line:

=

Hope that helps!

[Daniel Shub]

I will contribute:

;

[Majid Al-Sirafi]

dear Walter Roberson

I don't know what do you mean

[Walter Roberson]

Peter Weigel comments to Walter Roberson:

This comment is detrimental to the health of the MathWorks forums.

[Walter Roberson]

Peter Weigel: the MathWorks forums seem to have thrived in the five years since I posted that response to someone who asked a vague question and expected to be given full source without any effort on their part.

Answer 2

[RAJESH]

clc; clear all; close all;

% Initialization

iter = 1;

x = [0 0.25 0.5 0.75 1];

y = [5 6 3 2 8];

% Prepare X1 and Y1 matrices

X1 = zeros(4,4);

x1 = [x(3) x(4) x(5)];

x2 = [x(3) x(4) x(5)];

x3 = [x(1) x(2) x(3)];

x4 = [x(1) x(2) x(3) x(4)];

r = [length(x1) length(x2) length(x3) length(x4)];

X1(1,1:r(1)) = x1;

X1(2,1:r(2)) = x2;

X1(3,1:r(3)) = x3;

X1(4,1:r(4)) = x4;

Y1 = zeros(4,4);

y1 = [y(3) y(4) y(5)];

y2 = [y(3) y(4) y(5)];

y3 = [y(1) y(2) y(3)];

y4 = [y(1) y(2) y(3) y(4)];

r = [length(y1) length(y2) length(y3) length(y4)];

Y1(1,1:r(1)) = y1;

Y1(2,1:r(2)) = y2;

Y1(3,1:r(3)) = y3;

Y1(4,1:r(4)) = y4;

alpha = [-0.8 0.7 0.7 -0.8];

N = length(x);

% Initialize d and d1

d = zeros(1, N-1); % Adjust the size as needed

d1 = zeros(4, 4); % Adjust the size as needed

% Computation of a, b, and q values

for i = 1:N-1

a(i) = (x(i+1) - x(i)) / (X1(i, r(i)) - X1(i, 1));

b(i) = (X1(i, r(i)) * x(i) - X1(i, 1) * x(i+1)) / (X1(i, r(i)) - X1(i, 1));

% Calculating q(i) with careful attention to parentheses

term1 = (y(i) - alpha(i) * Y1(i, 1)) * (1 - (x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1))).^3;

term2 = (y(i+1) - alpha(i) * Y1(i, r(i))) * ((x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1))).^3;

term3 = (r(i) * (y(i) - alpha(i) * Y1(i, 1)) + (x(i+1) - x(i)) * d(i) - alpha(i) * d1(i, 1) * (X1(i, r(i)) - X1(i, 1))) * ...

(1 - (x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1))).^2 * (x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1));

term4 = (r(i) * (y(i+1) - alpha(i) * Y1(i, r(i))) - (x(i+1) - x(i)) * d(i+1) + alpha(i) * d1(i, r(i)) * (x1(i, r(i)) - x1(i, 1))) * ...

(1 - (x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1))) * ((x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1))).^2;

numerator = term1 + term2 + term3 + term4;

denominator = 1 + (r(i) - 3) * (1 - (x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1))) * ((x(i) - X1(i, 1)) / (X1(i, r(i)) - X1(i, 1)));

q(i) = numerator / denominator;

end

abq_values = [a' b' q'];

L = []; L1 = []; X = []; Y = [];

p = N;

for k = 1:iter

fprintf("ITERATION=%d\n", k)

for i = 1:N-1

for j = 1:p-2

if(k == 1) % First iteration

% Input data is (x,y) or given data

L(i,j) = a(i) * X(i,j) + b(i);

L1(i,j) = alpha(i) * Y1(i,j) + (q(i) * X1(i,j));

else % More than one iteration

% Input data is (X1, Y1) OR output after the first iteration

L(i,j) = a(i) * X(i,j) + b(i);

L1(i,j) = alpha(i) * Y(i,j) + (q(i) * X1(i,j));

end

end

X = [X L(i,:)];

Y = [Y L1(i,:)];

end

X1 = X;

Y1 = Y;

X = [];

Y = [];

g = [X1' Y1'];

g = str2num(num2str(g,10));

g = unique(g, 'rows');

X1 = g(:, 1);

Y1 = g(:, 2);

p = length(X1);

end

plot(x, y, '.k', 'markersize', 80);

hold on;

plot(X1, Y1, 'b-');

Index exceeds the number of array elements. Index must not exceed 4. Please give me correct program

Answer 3

[RAJESH]

term3 = r(i) * (y(i) - alpha(i) * Y1(i, 1)) + (x(i+1) - x(i)) * d(i) - alpha(i) * d1(i, 1) * (X1(i, t(i)) - X1(i, 1)) * ...

(1 - (x(i) - X1(i, 1)) / (X1(i, t(i)) - X1(i, 1))).^2 * (x(i) - X1(i, 1)) / (X1(i, t(i)) - X1(i, 1));

term4 = r(i) * (y(i+1) - alpha(i) * Y1(i, t(i))) - ((x(i+1) - x(i)) * d(i+1)) + alpha(i) * d1(i, t(i)) * (x1(i, t(i)) - x1(i, 1)) * ...

(1 - (x(i) - X1(i, 1)) / (X1(i, t(i)) - X1(i, 1))) * ((x(i) - X1(i, 1)) / (X1(i, t(i)) - X1(i, 1))).^2;

Index in position 1 exceeds array bounds. Index must not

exceed 1.

Error in rreplacetrrfcs (line 70)

term3 = r(i) * (y(i) - alpha(i) * Y1(i, 1)) + (x(i+1) - x(i)) * d(i) - alpha(i) * d1(i, 1) * (X1(i, t(i)) - X1(i, 1)) * ...

[DGM]

The error message means literally what it says. One of those indices is larger than the corresponding dimension of the array.

Which array is being indexed improperly? It's probably one of these 2-dimensional arrays:

• Y1(i, xxx)
• d1(i, xxx)
• X1(i, xxx)

Why is the array too short for the index? We have no way of knowing. It might be an initialization problem, or maybe a problem with incorrect array orientation or simply using the wrong variable name. We don't know what any of these abstract variable names mean or what is supposed to happen with them.