suzanne.soy/solvespace
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Scale columns of the Jacobian before least squares solving; this

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lets me reweight the parameters, e.g. to encourage the solver to
make changes to the point being dragged.

[git-p4: depot-paths = "//depot/solvespace/": change = 1719]
This commit is contained in:
Jonathan Westhues 2008-05-12 18:35:31 -08:00
parent 364938f332
commit 6031c99bec
2 changed files with 17 additions and 1 deletions
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2
solvespace.h
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@ -122,6 +122,8 @@ public:
double num[MAX_UNKNOWNS][MAX_UNKNOWNS];
} A;
double scale[MAX_UNKNOWNS];
// Some helpers for the least squares solve
double AAt[MAX_UNKNOWNS][MAX_UNKNOWNS];
double Z[MAX_UNKNOWNS];

16
system.cpp
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@ -273,6 +273,20 @@ bool System::SolveLinearSystem(double X[], double A[][MAX_UNKNOWNS],
bool System::SolveLeastSquares(void) {
int r, c, i;
// Scale the columns; this scale weights the parameters for the least
// squares solve, so that we can encourage the solver to make bigger
// changes in some parameters, and smaller in others.
for(c = 0; c < mat.n; c++) {
if(IsDragged(mat.param[c])) {
mat.scale[c] = 1/5.0;
} else {
mat.scale[c] = 1;
}
for(r = 0; r < mat.m; r++) {
mat.A.num[r][c] *= mat.scale[c];
}
}
// Write A*A'
for(r = 0; r < mat.m; r++) {
for(c = 0; c < mat.m; c++) { // yes, AAt is square
@ -292,7 +306,7 @@ bool System::SolveLeastSquares(void) {
for(i = 0; i < mat.m; i++) {
sum += mat.A.num[i][c]*mat.Z[i];
}
mat.X[c] = sum;
mat.X[c] = sum * mat.scale[c];
}
return true;
}