how to find lagrange multipliers value in SVM

matlab code:

   data=[1 1;2 2;2 3;1 4];
   labels=['x';'x';'y';'y'];

   if (1)
   svmStruct = svmtrain(data, labels, 'showplot',true); 
  else
    svmStruct = svmtrain(data, labels, 'kernel_function', 'linear','showplot',true);
  end

return;

my problem:

in svmtrain.m file how to find the value of "alpha" mathematically.

• i have some equations on lagrange multipliers(alpha) like...

-2a1-4a2+5a3+5a4-c+1=0

-4a1-8a2+10a3+10a4-c+1=0

5a1+10a2-13a3-14a4+c+1=0

5a1+10a2-14a3-17a4+c+1=0

a1+a2-a3-a4=0

where a1,a2,a3,a4 are lagrange multipliers and c is a constant

i tried in matlab to find solution for these equation but the matrix become nearly singular matrix.

these equations are inconsist but there any way to find these a1,a2,a3,a4,c values...

[Walter Roberson]

Reference: http://www.mathworks.com/matlabcentral/answers/27679-how-to-find-lagrange-multipliers-value-in-svm

Answer 1

[Walter Roberson]

No. In your earlier question on this subject, Anton proved that your equations are inconsistent. There is no solution for inconsistent equations. Every possible set of values will produce an inconsistency.

This is not an underdetermined system where there are multiple solutions and one needs to be found: this is a system whose equations cannot all be true.

Please go back and re-check your lagrange multiplier equations that you are solving.