gtsam/base/svdcmp.cpp

288 lines
6.2 KiB
C++

/**
* @file svdcmp.cpp
* @brief SVD decomposition adapted from NRC
* @author Alireza Fathi
* @author Frank Dellaert
*/
#include <stdexcept>
#include <math.h> /* for 'fabs' */
#include <iostream>
#include <vector>
#include <gtsam/base/Matrix.h>
using namespace std;
#define SIGN(a,b) ((b) >= 0.0 ? fabs(a) : -fabs(a))
static double sqrarg;
#define SQR(a) ((sqrarg=(a)) == 0.0 ? 0.0 : sqrarg*sqrarg)
static double maxarg1, maxarg2;
#define FMAX(a,b) (maxarg1=(a),maxarg2=(b),(maxarg1) > (maxarg2) ?\
(maxarg1) : (maxarg2))
static int iminarg1, iminarg2;
#define IMIN(a,b) (iminarg1=(a),iminarg2=(b),(iminarg1) < (iminarg2) ?\
(iminarg1) : (iminarg2))
/* ************************************************************************* */
/*
double pythag(double a, double b)
{
double absa = 0.0, absb = 0.0;
absa=fabs(a);
absb=fabs(b);
if (absa > absb) return absa*sqrt(1.0+SQR(absb/absa));
else return (absb == 0.0 ? 0.0 : absb*sqrt(1.0+SQR(absa/absb)));
}
*/
/* ************************************************************************* */
double pythag(double a, double b) {
double absa = 0.0, absb = 0.0;
absa = fabs(a);
absb = fabs(b);
if (absa > absb)
return absa * sqrt(1.0 + SQR(absb/absa));
else {
if (absb == 0.0)
return 0.0;
else
return (absb * sqrt(1.0 + SQR(absa/absb)));
}
}
/* ************************************************************************* */
void svdcmp(double **a, int m, int n, double w[], double **v, bool sort) {
int flag, i, its, j, jj, k, l, nm;
double anorm, c, f, g, h, s, scale, x, y, z;
//vector sizes:
// w[n] - q-1 passed in
// a[m] - u-1 passed in
// v[n] - v-1 passed in
//Current progress on verifying array bounds:
// rv1 references have been fixed
double *rv1 = new double[n];
g = 0.0;
scale = 0.0;
anorm = 0.0;
for (i = 1; i <= n; i++) {
l = i + 1;
rv1[i - 1] = scale * g;
g = s = scale = 0.0;
if (i <= m) {
for (k = i; k <= m; k++)
scale += fabs(a[k][i]);
if (scale) {
for (k = i; k <= m; k++) {
a[k][i] /= scale;
s += a[k][i] * a[k][i];
}
f = a[i][i];
g = -SIGN(sqrt(s),f);
h = f * g - s;
a[i][i] = f - g;
for (j = l; j <= n; j++) {
for (s = 0.0, k = i; k <= m; k++)
s += a[k][i] * a[k][j];
f = s / h;
for (k = i; k <= m; k++)
a[k][j] += f * a[k][i];
}
for (k = i; k <= m; k++)
a[k][i] *= scale;
}
}
w[i] = scale * g;
g = s = scale = 0.0;
if (i <= m && i != n) {
for (k = l; k <= n; k++)
scale += fabs(a[i][k]);
if (scale) {
for (k = l; k <= n; k++) {
a[i][k] /= scale;
s += a[i][k] * a[i][k];
}
f = a[i][l];
g = -SIGN(sqrt(s),f);
h = f * g - s;
a[i][l] = f - g;
for (k = l; k <= n; k++) {
rv1[k - 1] = a[i][k] / h;
}
for (j = l; j <= m; j++) {
for (s = 0.0, k = l; k <= n; k++)
s += a[j][k] * a[i][k];
for (k = l; k <= n; k++) {
a[j][k] += s * rv1[k - 1];
}
}
for (k = l; k <= n; k++)
a[i][k] *= scale;
}
}
anorm = FMAX(anorm,(fabs(w[i])+fabs(rv1[i-1])));
}
for (i = n; i >= 1; i--) {
if (i < n) {
if (g) {
for (j = l; j <= n; j++)
v[j][i] = (a[i][j] / a[i][l]) / g;
for (j = l; j <= n; j++) {
for (s = 0.0, k = l; k <= n; k++)
s += a[i][k] * v[k][j];
for (k = l; k <= n; k++)
v[k][j] += s * v[k][i];
}
}
for (j = l; j <= n; j++)
v[i][j] = v[j][i] = 0.0;
}
v[i][i] = 1.0;
g = rv1[i - 1];
l = i;
}
for (i = IMIN(m,n); i >= 1; i--) {
l = i + 1;
g = w[i];
for (j = l; j <= n; j++)
a[i][j] = 0.0;
if (g) {
g = 1.0 / g;
for (j = l; j <= n; j++) {
for (s = 0.0, k = l; k <= m; k++)
s += a[k][i] * a[k][j];
f = (s / a[i][i]) * g;
for (k = i; k <= m; k++)
a[k][j] += f * a[k][i];
}
for (j = i; j <= m; j++)
a[j][i] *= g;
} else
for (j = i; j <= m; j++)
a[j][i] = 0.0;
++a[i][i];
}
for (k = n; k >= 1; k--) {
for (its = 1; its <= 30; its++) {
flag = 1;
for (l = k; l >= 1; l--) {
nm = l - 1;
if ((double) (fabs(rv1[l - 1]) + anorm) == anorm) {
flag = 0;
break;
}
if ((double) (fabs(w[nm]) + anorm) == anorm)
break;
}
if (flag) {
c = 0.0;
s = 1.0;
for (i = l; i <= k; i++) {
f = s * rv1[i - 1];
rv1[i - 1] = c * rv1[i - 1];
if ((double) (fabs(f) + anorm) == anorm)
break;
g = w[i];
h = pythag(f, g);
w[i] = h;
h = 1.0 / h;
c = g * h;
s = -f * h;
for (j = 1; j <= m; j++) {
y = a[j][nm];
z = a[j][i];
a[j][nm] = y * c + z * s;
a[j][i] = z * c - y * s;
}
}
}
z = w[k];
if (l == k) {
if (z < 0.0) {
w[k] = -z;
for (j = 1; j <= n; j++)
v[j][k] = -v[j][k];
}
break;
}
if (its == 30)
throw(std::domain_error(
"no convergence in 30 svdcmp iterations"));
x = w[l];
nm = k - 1;
y = w[nm];
g = rv1[nm - 1];
h = rv1[k - 1];
f = ((y - z) * (y + z) + (g - h) * (g + h)) / (2.0 * h * y);
g = pythag(f, 1.0);
f = ((x - z) * (x + z) + h * ((y / (f + SIGN(g,f))) - h)) / x;
c = s = 1.0;
for (j = l; j <= nm; j++) {
i = j + 1;
g = rv1[i - 1];
y = w[i];
h = s * g;
g = c * g;
z = pythag(f, h);
rv1[j - 1] = z;
c = f / z;
s = h / z;
f = x * c + g * s;
g = g * c - x * s;
h = y * s;
y *= c;
for (jj = 1; jj <= n; jj++) {
x = v[jj][j];
z = v[jj][i];
v[jj][j] = x * c + z * s;
v[jj][i] = z * c - x * s;
}
z = pythag(f, h);
w[j] = z;
if (z) {
z = 1.0 / z;
c = f * z;
s = h * z;
}
f = c * g + s * y;
x = c * y - s * g;
for (jj = 1; jj <= m; jj++) {
y = a[jj][j];
z = a[jj][i];
a[jj][j] = y * c + z * s;
a[jj][i] = z * c - y * s;
}
}
rv1[l - 1] = 0.0;
rv1[k - 1] = f;
w[k] = x;
}
}
if (sort) {
for (int i1 = 1; i1 <= n; i1++) {
for (int i2 = i1+1; i2 <= n; i2++) {
if (w[i1] < w[i2]) {
double temp = w[i1];
w[i1] = w[i2];
w[i2] = temp;
for (int j = 1; j <= n; j++) {
double temp1 = v[j][i1];
v[j][i1] = v[j][i2];
v[j][i2] = temp1;
}
}
}
}
}
delete[] rv1;
}
/* ************************************************************************* */