elpa_eigenvalues \- computes the eigenvales of a real symmetric or complex hermetian matrix
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.SH SYNOPSIS
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.SS FORTRAN INTERFACE
use elpa
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class(elpa_t), pointer :: elpa
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.RI "call elpa%\fBeigenvalues\fP (a, ev, error)"
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.RI " "
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.RI "With the definintions of the input and output variables:"
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.RI "class(elpa_t) :: \fBelpa\fP ! returns an instance of the ELPA object"
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.TP
.RI "datatype :: \fBa\fP"
The matrix a for which the eigenvalues should be computed. The dimensions of matrix a must be set \fIBEFORE\fP with the methods \fBelpa_set\fP(3) and \fBelpa_setup\fP(3). The datatype of the matrix can be one of "real(kind=c_double)", "real(kind=c_float)", "complex(kind=c_double)", or "complex(kind=c_float)"
.TP
.RI "datatype :: \fBev\fP"
The vector ev where the eigenvalues will be stored in \fIascending\fP order. The datatype of the vector ev can be either "real(kind=c_double)", or "real(kind=c_float)", depending of the datatype of the matrix. Note that complex hermetian matrices also have real valued eigenvalues.
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.RI "integer, optional :: \fBerror\fP"
The return error code of the function. Should be "ELPA_OK". The error code can be querried with the function \fBelpa_strerr\fP(3)
.RI "With the definintions of the input and output variables:"
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.TP
.RI "elpa_t \fBhandle\fP;"
The handle to the ELPA object
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.RI "datatype *\fBa\fP;"
The matrix a for which the eigenvalues should be computed. The dimensions of the matrix must be set \fIBEFORE\fP with the methods \fBelpa_set\fP(3) and \fBelpa_setup\fP(3). The \fBdatatype\fP can be one of "double", "float", "double complex", or "float complex".
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.RI "datatype *\fBev\fP;"
The storage for the computed eigenvalues. Eigenvalues will be stored in \fIascendig\fP order. The \fBdatatype\fP can be either "double" or "float". Note that the eigenvalues of complex hermetian matrices are also real.
.SH DESCRIPTION
Compute the the eigenvalues of a real symmtric or complex hermetian matrix.The functions \fBelpa_init\fP(3), \fBelpa_allocate\fP(3), \fBelpa_set\fP(3), and \fBelpa_setup\fP(3) must be called \fIBEFORE\fP \fBelpa_eigenvalues\fP can be called.
