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![François Coppens](/assets/img/avatar_default.png)
decomposition in the Fortran code and made a basic call to the subroutine MYSUBROUTINE, which is bound to the C++ void function 'Sherman-Morrison();. For now compilation fails with lots of undefined references.'
111 lines
3.3 KiB
C++
111 lines
3.3 KiB
C++
// SM-MaponiA3.cpp
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// Algorithm 3 from P. Maponi,
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// p. 283, doi:10.1016/j.laa.2006.07.007
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#include "SM_MaponiA3.hpp"
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#include "Helpers.hpp"
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void Sherman_Morrison(int **Slater0, double **Slater_inv, unsigned int *Dim, unsigned int *N_updates, int **Updates, unsigned int *Updates_index) {
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unsigned int k, l, lbar, i, j, tmp, M = *Dim;
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unsigned int *p = new unsigned int[M+1];
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unsigned int **Id = new unsigned int*[M];
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double alpha, beta;
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double **U, *breakdown = new double[M+1];
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double **Al = new double*[M];
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p[0] = 0;
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for (i = 0; i < M; i++) {
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p[i+1] = i + 1;
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Id[i] = new unsigned int[M];
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Al[i] = new double[M];
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}
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// Declare auxiliary solution matrix ylk
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double ***ylk = new double**[M];
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for (l = 0; l < M; l++) {
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ylk[l] = new double*[M+1];
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for (k = 0; k < M+1; k++) {
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ylk[l][k] = new double[M+1];
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}
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}
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// Initialize identity matrix
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for (i = 0; i < M; i++) {
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for (j = 0; j < M; j++) {
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if (i != j) Id[i][j] = 0;
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else Id[i][j] = 1;
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}
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}
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// Initialize ylk with zeros
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for (l = 0; l < M; l++) {
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for (k = 0; k < M+1; k++) {
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for (i = 0; i < M+1; i++) {
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ylk[l][k][i] = 0;
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}
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}
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}
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// Calculate all the y0k in M^2 multiplications instead of M^3
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for (k = 1; k < M+1; k++) {
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for (i = 1; i < M+1; i++) {
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ylk[0][k][i] = Slater_inv[i-1][i-1] * Updates[i-1][k-1];
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}
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}
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// Calculate all the ylk from the y0k
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for (l = 1; l < M; l++) {
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for (j = l; j < M+1; j++) {
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breakdown[j] = abs( 1 + ylk[l-1][p[j]][p[j]] );
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}
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lbar = getMaxIndex(breakdown, M+1);
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for (i = 0; i < M; i++) {
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breakdown[i] = 0;
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}
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tmp = p[l];
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p[l] = p[lbar];
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p[lbar] = tmp;
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for (k = l+1; k < M+1; k++) {
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beta = 1 + ylk[l-1][p[l]][p[l]];
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if (beta == 0) {
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cout << "Break-down condition occured. Exiting..." << endl;
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exit;
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}
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for (i = 1; i < M+1; i++) {
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alpha = ylk[l-1][p[k]][p[l]] / beta;
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ylk[l][p[k]][i] = ylk[l-1][p[k]][i] - alpha * ylk[l-1][p[l]][i];
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}
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}
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}
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// Construct A-inverse from A0-inverse and the ylk
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// Keep the memory location of the passed array 'Slater_inv' before 'Slater_inv'
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// gets reassigned by 'matMul(...)' in the next line, by creating a new
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// pointer 'copy' that points to whereever 'Slater_inv' points to now.
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double **copy = Slater_inv;
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for (l = 0; l < M; l++) {
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k = l+1;
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U = outProd(ylk[l][p[k]], Id[p[k]-1], M);
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beta = 1 + ylk[l][p[k]][p[k]];
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for (i = 0; i < M; i++) {
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for (j = 0; j < M; j++) {
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Al[i][j] = Id[i][j] - U[i][j] / beta;
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}
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}
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Slater_inv = matMul(Al, Slater_inv, M);
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}
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// Assign the new values of 'Slater_inv' to the old values in 'copy[][]'
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for (i = 0; i < M; i++) {
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for (j = 0; j < M; j++) {
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copy[i][j] = Slater_inv[i][j];
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}
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}
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for (l = 0; l < M; l++) {
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for (k = 0; k < M+1; k++) {
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delete [] ylk[l][k];
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}
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delete [] ylk[l], Id[l], U[l], Al[l], Slater_inv[l];
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}
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delete [] p, breakdown;
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} |