https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Eigenproblem/m-p/904202#M11531 Hi,<BR /> I'm new to Lapack libraries and Intel MKL.<BR /> I have to solve an eigensystem problem, with 3x3 complex matrixes, and I don't know if I'm calling Lapack routines in the correct order. I use these routines from C. Here is the list:<BR />First I call <BR /><B>zgebal</B><BR />with job ='P'.<BR />Then I call<BR /><B>zgehdr</B>.<BR />Then i copy the Hessenberg matrix to a temporary matrix, and the temporary one I put as input to:<BR /><B>unghr</B><BR />to get the Q matrix.<BR />After that:<BR /><B>zhseqr</B><BR />with <BR />job = 'S' and compz = 'V'; matrix inputs are the Hessemberg matrix, and as vl the Q matrix.<BR />Then I call<BR /><B>zgebak</B><BR />with the same Q matrix (modified by hseqr, so eigenvectors are in).<BR />Finally<BR /><B>ztrevc</B><BR />is called.<BR /><BR />Also, I wish to know if somebody have some example of how to use this functions.<BR /><BR />Thank you.<BR /> Mon, 23 Oct 2006 19:29:57 GMT fernet 2006-10-23T19:29:57Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Eigenproblem/m-p/904202#M11531 Hi,<BR /> I'm new to Lapack libraries and Intel MKL.<BR /> I have to solve an eigensystem problem, with 3x3 complex matrixes, and I don't know if I'm calling Lapack routines in the correct order. I use these routines from C. Here is the list:<BR />First I call <BR /><B>zgebal</B><BR />with job ='P'.<BR />Then I call<BR /><B>zgehdr</B>.<BR />Then i copy the Hessenberg matrix to a temporary matrix, and the temporary one I put as input to:<BR /><B>unghr</B><BR />to get the Q matrix.<BR />After that:<BR /><B>zhseqr</B><BR />with <BR />job = 'S' and compz = 'V'; matrix inputs are the Hessemberg matrix, and as vl the Q matrix.<BR />Then I call<BR /><B>zgebak</B><BR />with the same Q matrix (modified by hseqr, so eigenvectors are in).<BR />Finally<BR /><B>ztrevc</B><BR />is called.<BR /><BR />Also, I wish to know if somebody have some example of how to use this functions.<BR /><BR />Thank you.<BR /> Mon, 23 Oct 2006 19:29:57 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Eigenproblem/m-p/904202#M11531 fernet 2006-10-23T19:29:57Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Eigenproblem/m-p/904203#M11532 Nobody knows?<BR /><BR />It was so easy... I don't understand the time I've lost looking for this easy function:<BR /><B>?geev</B><BR /> Tue, 24 Oct 2006 16:25:48 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Eigenproblem/m-p/904203#M11532 fernet 2006-10-24T16:25:48Z