Computes selected eigenvalues and, optionally, eigenvectors of a real symmetric matrix using Relatively Robust Representation.
p?syevrcomputes selected eigenvalues and, optionally, eigenvectors of a real symmetric matrix
Adistributed in 2D blockcyclic format by calling the recommended sequence of ScaLAPACK
First, the matrix
Ais reduced to real symmetric tridiagonal form. Then, the eigenproblem is solved using the parallel MRRR algorithm. Last, if eigenvectors have been computed, a backtransformation is done.
Upon successful completion, each processor stores a copy of all computed eigenvalues in
w. The eigenvector matrix
zis stored in 2D block-cyclic format distributed over all processors.
Note that subsets of eigenvalues/vectors can be selected by specifying a range of values or a range of indices for the desired eigenvalues.
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.
Notice revision #20110804
This notice covers the following instruction sets: SSE2, SSE4.2, AVX2, AVX-512.
- (global)CHARACTER*1Specifies whether or not to compute the eigenvectors:= 'N': Compute eigenvalues only.= 'V': Compute eigenvalues and eigenvectors.
- (global)CHARACTER*1= 'A': all eigenvalues will be found.= 'V': all eigenvalues in the interval [vl,vu] will be found.= 'I': theil-th throughiu-th eigenvalues will be found.
- (global)CHARACTER*1Specifies whether the upper or lower triangular part of the symmetric matrixAis stored:= 'U': Upper triangular= 'L': Lower triangular
- (global )INTEGERThe number of rows and columns of the matrixa.n≥0
- REALforpssyevrDOUBLE PRECISIONforpdsyevrBlock cyclic array of global size(, local sizen,n)(lld_a,(LOCc