Dear R Users , 
 
As a beginner in QP, I'm trying to solve a Support Vector Machine problem by a QP. In particulare I am using the quadprog package.
My questions are here: 
1- In the document for the package (The quadprog Package), the inequality constraint is mentioned with >= , however in a standard QP, this usaully is written with <= . This constraint should be multiplied by a negativity sign to be standard ? 
2- How about nonnegativity constraints ? Are that possible to be handled via upper and lower bounds? In document, nonnegativity is not mentioned. Is there any argument for that? 
3- In QP formulation we have a constant 1/2 in objective function. This should be multiplied by the user or it is done by the algorithm? 
4- More important, when I multiply a b*b matrix by D in quadratic term of objective function, I get thise message: 
Error in solve.QP(Dmat, dvec, Amat, bvec) : 
       matrix D in quadratic function is not positive definite! 
How to multiply b*b matrix by the diagonal matrix ? 


Thank you very much for any help. 

Amir 

       
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