Rename the variables for the linear system to solve, for a bit more

clarity.

[git-p4: depot-paths = "//depot/solvespace/": change = 1676]
This commit is contained in:
Jonathan Westhues 2008-04-20 17:26:36 -08:00
parent b78b10ac1a
commit 7220f998fc
2 changed files with 94 additions and 90 deletions

View File

@ -86,24 +86,27 @@ public:
static const int ASSUMED = 10000; static const int ASSUMED = 10000;
static const int SUBSTITUTED = 10001; static const int SUBSTITUTED = 10001;
// The Jacobian matrix // The system Jacobian matrix
struct { struct {
hEquation eq[MAX_UNKNOWNS]; // The corresponding equation for each row
hEquation eq[MAX_UNKNOWNS];
// The corresponding parameter for each column
hParam param[MAX_UNKNOWNS];
bool bound[MAX_UNKNOWNS];
// We're solving AX = B
int m, n;
struct {
Expr *sym[MAX_UNKNOWNS][MAX_UNKNOWNS];
double num[MAX_UNKNOWNS][MAX_UNKNOWNS];
} A;
double X[MAX_UNKNOWNS];
struct { struct {
Expr *sym[MAX_UNKNOWNS]; Expr *sym[MAX_UNKNOWNS];
double num[MAX_UNKNOWNS]; double num[MAX_UNKNOWNS];
} B; } B;
} mat;
hParam param[MAX_UNKNOWNS];
bool bound[MAX_UNKNOWNS];
Expr *sym[MAX_UNKNOWNS][MAX_UNKNOWNS];
double num[MAX_UNKNOWNS][MAX_UNKNOWNS];
double X[MAX_UNKNOWNS];
int m, n;
} J;
bool Tol(double v); bool Tol(double v);
void GaussJordan(void); void GaussJordan(void);

View File

@ -7,31 +7,31 @@ void System::WriteJacobian(int eqTag, int paramTag) {
for(a = 0; a < param.n; a++) { for(a = 0; a < param.n; a++) {
Param *p = &(param.elem[a]); Param *p = &(param.elem[a]);
if(p->tag != paramTag) continue; if(p->tag != paramTag) continue;
J.param[j] = p->h; mat.param[j] = p->h;
j++; j++;
} }
J.n = j; mat.n = j;
i = 0; i = 0;
for(a = 0; a < eq.n; a++) { for(a = 0; a < eq.n; a++) {
Equation *e = &(eq.elem[a]); Equation *e = &(eq.elem[a]);
if(e->tag != eqTag) continue; if(e->tag != eqTag) continue;
J.eq[i] = eq.elem[i].h; mat.eq[i] = eq.elem[i].h;
J.B.sym[i] = eq.elem[i].e; mat.B.sym[i] = eq.elem[i].e;
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
J.sym[i][j] = e->e->PartialWrt(J.param[j]); mat.A.sym[i][j] = e->e->PartialWrt(mat.param[j]);
} }
i++; i++;
} }
J.m = i; mat.m = i;
} }
void System::EvalJacobian(void) { void System::EvalJacobian(void) {
int i, j; int i, j;
for(i = 0; i < J.m; i++) { for(i = 0; i < mat.m; i++) {
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
J.num[i][j] = (J.sym[i][j])->Eval(); mat.A.num[i][j] = (mat.A.sym[i][j])->Eval();
} }
} }
} }
@ -43,18 +43,18 @@ bool System::Tol(double v) {
void System::GaussJordan(void) { void System::GaussJordan(void) {
int i, j; int i, j;
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
J.bound[j] = false; mat.bound[j] = false;
} }
// Now eliminate. // Now eliminate.
i = 0; i = 0;
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
// First, seek a pivot in our column. // First, seek a pivot in our column.
int ip, imax; int ip, imax;
double max = 0; double max = 0;
for(ip = i; ip < J.m; ip++) { for(ip = i; ip < mat.m; ip++) {
double v = fabs(J.num[ip][j]); double v = fabs(mat.A.num[ip][j]);
if(v > max) { if(v > max) {
imax = ip; imax = ip;
max = v; max = v;
@ -63,96 +63,96 @@ void System::GaussJordan(void) {
if(!Tol(max)) { if(!Tol(max)) {
// There's a usable pivot in this column. Swap it in: // There's a usable pivot in this column. Swap it in:
int js; int js;
for(js = j; js < J.n; js++) { for(js = j; js < mat.n; js++) {
double temp; double temp;
temp = J.num[imax][js]; temp = mat.A.num[imax][js];
J.num[imax][js] = J.num[i][js]; mat.A.num[imax][js] = mat.A.num[i][js];
J.num[i][js] = temp; mat.A.num[i][js] = temp;
} }
// Get a 1 as the leading entry in the row we're working on. // Get a 1 as the leading entry in the row we're working on.
double v = J.num[i][j]; double v = mat.A.num[i][j];
for(js = 0; js < J.n; js++) { for(js = 0; js < mat.n; js++) {
J.num[i][js] /= v; mat.A.num[i][js] /= v;
} }
// Eliminate this column from rows except this one. // Eliminate this column from rows except this one.
int is; int is;
for(is = 0; is < J.m; is++) { for(is = 0; is < mat.m; is++) {
if(is == i) continue; if(is == i) continue;
// We're trying to drive J.num[is][j] to zero. We know // We're trying to drive A[is][j] to zero. We know
// that J.num[i][j] is 1, so we want to subtract off // that A[i][j] is 1, so we want to subtract off
// J.num[is][j] times our present row. // A[is][j] times our present row.
double v = J.num[is][j]; double v = mat.A.num[is][j];
for(js = 0; js < J.n; js++) { for(js = 0; js < mat.n; js++) {
J.num[is][js] -= v*J.num[i][js]; mat.A.num[is][js] -= v*mat.A.num[i][js];
} }
J.num[is][j] = 0; mat.A.num[is][j] = 0;
} }
// And mark this as a bound variable. // And mark this as a bound variable.
J.bound[j] = true; mat.bound[j] = true;
// Move on to the next row, since we just used this one to // Move on to the next row, since we just used this one to
// eliminate from column j. // eliminate from column j.
i++; i++;
if(i >= J.m) break; if(i >= mat.m) break;
} }
} }
} }
bool System::SolveLinearSystem(void) { bool System::SolveLinearSystem(void) {
if(J.m != J.n) oops(); if(mat.m != mat.n) oops();
// Gaussian elimination, with partial pivoting. It's an error if the // Gaussian elimination, with partial pivoting. It's an error if the
// matrix is singular, because that means two constraints are // matrix is singular, because that means two constraints are
// equivalent. // equivalent.
int i, j, ip, jp, imax; int i, j, ip, jp, imax;
double max, temp; double max, temp;
for(i = 0; i < J.m; i++) { for(i = 0; i < mat.m; i++) {
// We are trying eliminate the term in column i, for rows i+1 and // We are trying eliminate the term in column i, for rows i+1 and
// greater. First, find a pivot (between rows i and N-1). // greater. First, find a pivot (between rows i and N-1).
max = 0; max = 0;
for(ip = i; ip < J.m; ip++) { for(ip = i; ip < mat.m; ip++) {
if(fabs(J.num[ip][i]) > max) { if(fabs(mat.A.num[ip][i]) > max) {
imax = ip; imax = ip;
max = fabs(J.num[ip][i]); max = fabs(mat.A.num[ip][i]);
} }
} }
if(fabs(max) < 1e-12) return false; if(fabs(max) < 1e-12) return false;
// Swap row imax with row i // Swap row imax with row i
for(jp = 0; jp < J.n; jp++) { for(jp = 0; jp < mat.n; jp++) {
temp = J.num[i][jp]; temp = mat.A.num[i][jp];
J.num[i][jp] = J.num[imax][jp]; mat.A.num[i][jp] = mat.A.num[imax][jp];
J.num[imax][jp] = temp; mat.A.num[imax][jp] = temp;
} }
temp = J.B.num[i]; temp = mat.B.num[i];
J.B.num[i] = J.B.num[imax]; mat.B.num[i] = mat.B.num[imax];
J.B.num[imax] = temp; mat.B.num[imax] = temp;
// For rows i+1 and greater, eliminate the term in column i. // For rows i+1 and greater, eliminate the term in column i.
for(ip = i+1; ip < J.m; ip++) { for(ip = i+1; ip < mat.m; ip++) {
temp = J.num[ip][i]/J.num[i][i]; temp = mat.A.num[ip][i]/mat.A.num[i][i];
for(jp = 0; jp < J.n; jp++) { for(jp = 0; jp < mat.n; jp++) {
J.num[ip][jp] -= temp*(J.num[i][jp]); mat.A.num[ip][jp] -= temp*(mat.A.num[i][jp]);
} }
J.B.num[ip] -= temp*J.B.num[i]; mat.B.num[ip] -= temp*mat.B.num[i];
} }
} }
// We've put the matrix in upper triangular form, so at this point we // We've put the matrix in upper triangular form, so at this point we
// can solve by back-substitution. // can solve by back-substitution.
for(i = J.m - 1; i >= 0; i--) { for(i = mat.m - 1; i >= 0; i--) {
if(fabs(J.num[i][i]) < 1e-10) return false; if(fabs(mat.A.num[i][i]) < 1e-10) return false;
temp = J.B.num[i]; temp = mat.B.num[i];
for(j = J.n - 1; j > i; j--) { for(j = mat.n - 1; j > i; j--) {
temp -= J.X[j]*J.num[i][j]; temp -= mat.X[j]*mat.A.num[i][j];
} }
J.X[i] = temp / J.num[i][i]; mat.X[i] = temp / mat.A.num[i][i];
} }
return true; return true;
@ -160,17 +160,17 @@ bool System::SolveLinearSystem(void) {
bool System::NewtonSolve(int tag) { bool System::NewtonSolve(int tag) {
WriteJacobian(tag, tag); WriteJacobian(tag, tag);
if(J.m != J.n) oops(); if(mat.m != mat.n) oops();
int iter = 0; int iter = 0;
bool converged = false; bool converged = false;
int i; int i;
do { do {
// Evaluate the functions numerically // Evaluate the functions numerically
for(i = 0; i < J.m; i++) { for(i = 0; i < mat.m; i++) {
J.B.num[i] = (J.B.sym[i])->Eval(); mat.B.num[i] = (mat.B.sym[i])->Eval();
dbp("J.B.num[%d] = %.3f", i, J.B.num[i]); dbp("mat.B.num[%d] = %.3f", i, mat.B.num[i]);
dbp("J.B.sym[%d] = %s", i, (J.B.sym[i])->Print()); dbp("mat.B.sym[%d] = %s", i, (mat.B.sym[i])->Print());
} }
// And likewise for the Jacobian // And likewise for the Jacobian
EvalJacobian(); EvalJacobian();
@ -179,19 +179,20 @@ bool System::NewtonSolve(int tag) {
// Take the Newton step; // Take the Newton step;
// J(x_n) (x_{n+1} - x_n) = 0 - F(x_n) // J(x_n) (x_{n+1} - x_n) = 0 - F(x_n)
for(i = 0; i < J.m; i++) { for(i = 0; i < mat.m; i++) {
dbp("J.X[%d] = %.3f", i, J.X[i]); dbp("mat.X[%d] = %.3f", i, mat.X[i]);
dbp("modifying param %08x, now %.3f", J.param[i], dbp("modifying param %08x, now %.3f", mat.param[i],
param.FindById(J.param[i])->val); param.FindById(mat.param[i])->val);
(param.FindById(J.param[i]))->val -= J.X[i]; (param.FindById(mat.param[i]))->val -= mat.X[i];
// XXX do this properly // XXX do this properly
SS.GetParam(J.param[i])->val = (param.FindById(J.param[i]))->val; SS.GetParam(mat.param[i])->val =
(param.FindById(mat.param[i]))->val;
} }
// XXX re-evaluate functions before checking convergence // XXX re-evaluate functions before checking convergence
converged = true; converged = true;
for(i = 0; i < J.m; i++) { for(i = 0; i < mat.m; i++) {
if(!Tol(J.B.num[i])) { if(!Tol(mat.B.num[i])) {
converged = false; converged = false;
break; break;
} }
@ -218,23 +219,23 @@ bool System::Solve(void) {
WriteJacobian(0, 0); WriteJacobian(0, 0);
EvalJacobian(); EvalJacobian();
for(i = 0; i < J.m; i++) { for(i = 0; i < mat.m; i++) {
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
dbp("J[%d][%d] = %.3f", i, j, J.num[i][j]); dbp("A[%d][%d] = %.3f", i, j, mat.A.num[i][j]);
} }
} }
GaussJordan(); GaussJordan();
dbp("bound states:"); dbp("bound states:");
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
dbp(" param %08x: %d", J.param[j], J.bound[j]); dbp(" param %08x: %d", mat.param[j], mat.bound[j]);
} }
// Fix any still-free variables wherever they are now. // Fix any still-free variables wherever they are now.
for(j = 0; j < J.n; j++) { for(j = 0; j < mat.n; j++) {
if(J.bound[j]) continue; if(mat.bound[j]) continue;
param.FindById(J.param[j])->tag = ASSUMED; param.FindById(mat.param[j])->tag = ASSUMED;
} }
NewtonSolve(0); NewtonSolve(0);