how can I do this fast addition and multiplication?

Hi all,

I am transforming some data using an equation that involves a multiplication and addition. (Please see line 20 in the full code below this post., i.e. the following line:

newdata1 = (((R)*X1_full(:,i))+ T)';

In this example, I only have 4 data points (i.e. in the 'X1_full' variable). So speed is not a problem using the FOR loop. However, my actual dataset is very large (2 million data points). Any suggestion to improve the speed will be helpful.

cheers. K.

clc;clear all;close all

% input data to transform
  X1_full = [1 2 3 5;
             45 8 7 95;
             12 78 98 3]

           % R and T are transform params
           T = [292.213040777858;78.1087497964877;865.7398878749]

           R=[0.999998463087434,8.08983068375718e-05,-0.00175136467802407;
               -8.44379283493625e-05,0.999997954040306,-0.00202108521267277;
               0.00175119759243091,0.00202122998804671,0.999996423961770;]

% Loop through all data and transform
for i = 1:size(X1_full,2)

% Formula to transform the input data
newdata1 = (((R)*X1_full(:,i))+ T)';

Savenewdata1(i,:) = newdata1

end

Answer 1

[Michael Haderlein]

Savenewdata1=bsxfun(@plus,(R*X1_full),T)';

can replace your loop and should be faster than your solution.

[Kate]

thank you Michael.