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update code documentation

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Krishna Vedala 2020-05-25 18:13:43 -04:00
parent 4e832b8e96
commit b2632cdcad
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1 changed files with 6 additions and 2 deletions
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8
numerical_methods/qr_eigen_values.c
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@ -1,6 +1,6 @@
/**
* @file
* Compute eigen values and eigen vectors of a matrix using QR decomposition method.
* Compute real eigen values and eigen vectors of a symmetric matrix using QR decomposition method.
*/
#include <stdio.h>
#include <math.h>
@ -83,6 +83,8 @@ int main(int argc, char **argv)
double **A = (double **)malloc(sizeof(double) * mat_size);
double **R = (double **)malloc(sizeof(double) * mat_size);
double **Q = (double **)malloc(sizeof(double) * mat_size);
/* number of eigen values = matrix size */
double *eigen_vals = (double *)malloc(sizeof(double) * mat_size);
if (!Q || !R || !eigen_vals)
{
@ -111,8 +113,9 @@ int main(int argc, char **argv)
function_timer *t1 = new_timer();
start_timer(t1);
while (num_eigs > 0)
while (num_eigs > 0) /* continue till all eigen values are found */
{
/* iterate with QR decomposition */
while (fabs(A[num_eigs][num_eigs - 1]) > 1e-10)
{
last_eig = A[num_eigs][num_eigs];
@ -131,6 +134,7 @@ int main(int argc, char **argv)
A[i][i] += last_eig; /* A + cI */
}
/* store the converged eigen value */
eigen_vals[num_eigs] = A[num_eigs][num_eigs];
#if defined(DEBUG) || !defined(NDEBUG)
printf("========================\n");