https://community.intel.com/t5/Intel-Integrated-Performance/EigenValuesVectorsSym/m-p/905073#M13317 I want to calculate the eigenvalues/eigenvectors of a real symmetric matrix. According to the documentation only the lower triangular part of the input matrix is used. In my understanding this<BR /><BR />double buffer[4];<BR />double values[2];<BR />double vectors[4];<BR />double A[2 * 2] = { 1, 0, 2, 3};<BR />ippmEigenValuesVectorsSym_m_64f(A, 2 * sizeof(double), sizeof(double), buffer, vectors, 2 * sizeof(double), sizeof(double), values, 2);<BR /><BR />should calculate the eigenvectors/eigenvalues for the matrix:<BR />M=[1, 2;<BR /> 2, 3];<BR /><BR />But this yields the result for M=[1, 0; 0; 3]. Only if i specifing A as A[2*2]={ 1, 2, 0, 3} i get the correct result.<BR /><BR />Am i missing somehting here?<BR /><BR />Thanks in advance,<BR />Michael<BR /> Fri, 11 Apr 2008 14:15:05 GMT michael_burisch 2008-04-11T14:15:05Z https://community.intel.com/t5/Intel-Integrated-Performance/EigenValuesVectorsSym/m-p/905073#M13317 I want to calculate the eigenvalues/eigenvectors of a real symmetric matrix. According to the documentation only the lower triangular part of the input matrix is used. In my understanding this<BR /><BR />double buffer[4];<BR />double values[2];<BR />double vectors[4];<BR />double A[2 * 2] = { 1, 0, 2, 3};<BR />ippmEigenValuesVectorsSym_m_64f(A, 2 * sizeof(double), sizeof(double), buffer, vectors, 2 * sizeof(double), sizeof(double), values, 2);<BR /><BR />should calculate the eigenvectors/eigenvalues for the matrix:<BR />M=[1, 2;<BR /> 2, 3];<BR /><BR />But this yields the result for M=[1, 0; 0; 3]. Only if i specifing A as A[2*2]={ 1, 2, 0, 3} i get the correct result.<BR /><BR />Am i missing somehting here?<BR /><BR />Thanks in advance,<BR />Michael<BR /> Fri, 11 Apr 2008 14:15:05 GMT https://community.intel.com/t5/Intel-Integrated-Performance/EigenValuesVectorsSym/m-p/905073#M13317 michael_burisch 2008-04-11T14:15:05Z