1 | <title>RG</title> |
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2 | <h2>SUBROUTINE RG(NM,N,A,WR,WI,MATZ,Z,IV1,FV1,IERR)</h2> |
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3 | |
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4 | RG calls the recommended sequence of EISPACK subroutines to |
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5 | find the eigenvalues and, if desired, the eigenvectors of a |
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6 | real, general matrix. |
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7 | <p> |
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8 | <dl> |
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9 | <p><dt><b>NM</b> |
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10 | <dd>Input, INTEGER NM, the row dimension (first dimension) of the two |
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11 | dimensional arrays as declared in the calling program. |
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12 | |
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13 | <p><dt><b>N</b> |
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14 | <dd>Input, INTEGER N, the order (=size=number of rows=number of columns) |
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15 | of the matrix whose eigenvalues are sought. |
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16 | |
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17 | <p><dt><b>A</b> |
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18 | <dd>Input/output, REAL A(NM,N), on input, the matrix, which is overwritten |
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19 | on output. |
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20 | |
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21 | <p><dt><b>WR</b> |
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22 | <dd>Output, REAL WR(N), the real parts of the eigenvalues. |
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23 | |
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24 | <p><dt><b>WI</b> |
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25 | <dd>Output, REAL WI(N), the imaginary parts of the eigenvalues. |
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26 | |
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27 | <p><dt><b>MATZ</b> |
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28 | <dd>Input, INTEGER MATZ, set to 0 if only eigenvalues are desired. |
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29 | Otherwise all eigenvectors will also be calculated. |
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30 | |
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31 | <p><dt><b>Z</b> |
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32 | <dd>Output, REAL Z(NM,N), if MATZ is not zero, Z contains the |
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33 | eigenvectors of A. If the J-th eigenvalue is real, the |
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34 | J-th column of Z is its eigenvector. If the J-th |
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35 | eigenvalue is complex with positive real part (then the |
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36 | J+1-th eigenvalue is its complex conjugate), its eigenvector |
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37 | has real part in the J-th column of Z and imaginary part |
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38 | in the J+1-th column of Z. |
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39 | |
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40 | <p><dt><b>IV1</b> |
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41 | <dd>Work vector, INTEGER IV1(N). |
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42 | |
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43 | <p><dt><b>FV1</b> |
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44 | <dd>Work vector, REAL FV1(N). |
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45 | |
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46 | <p><dt><b>IERR</b> |
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47 | <dd>Output, INTEGER IERR, an error flag. 0 if no errors, or |
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48 | J if eigenvalues 1 through J were not found. |
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49 | </dl> |
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50 | <p> |
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58 | <hr> |
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59 | <font size=-1> |
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60 | <i><a href=/copyright.html>©</a> Pittsburgh Supercomputing Center (PSC)<br> |
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61 | Revised: October 1996 <br> |
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62 | </i></font> |
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63 | <font size=-2> |
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64 | <i>URL: http://www.psc.edu/general/software/packages/eispack/subroutines/rg.html</i> |
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65 | </font> |
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67 | |
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68 | |
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