/**
* Eliminate the columns corresponding to a list of eliminated parameters.
* @param M the constraints matrix whose columns are to be removed
* @param nbVars an offset to be added to the ranks of the variables to be
* removed
* @param elimParms the list of ranks of the variables to be removed
* @param newM (output) the matrix without the removed columns
*/
void Constraints_removeElimCols(Matrix * M, unsigned int nbVars,
unsigned int *elimParms, Matrix ** newM) {
unsigned int i, j, k;
if (elimParms[0]==0) {
Matrix_clone(M, newM);
return;
}
if ((*newM)==NULL) {
(*newM) = Matrix_Alloc(M->NbRows, M->NbColumns - elimParms[0]);
}
else {
assert ((*newM)->NbColumns==M->NbColumns - elimParms[0]);
}
for (i=0; i< M->NbRows; i++) {
value_assign((*newM)->p[i][0], M->p[i][0]); /* kind of cstr */
k=0;
Vector_Copy(&(M->p[i][1]), &((*newM)->p[i][1]), nbVars);
for (j=0; j< M->NbColumns-2-nbVars; j++) {
if (j!=elimParms[k+1]) {
value_assign((*newM)->p[i][j-k+nbVars+1], M->p[i][j+nbVars+1]);
}
else {
k++;
}
}
value_assign((*newM)->p[i][(*newM)->NbColumns-1],
M->p[i][M->NbColumns-1]); /* cst part */
}
} /* Constraints_removeElimCols */
Matrix* Matrix_minor(Matrix *mat, int x, int y){
Matrix *temp = Matrix_clone(mat);
Matrix *newmat = Matrix_create(temp->rows - 1, temp->cols - 1);
int i,j;
int n = temp->rows;
int m = temp->cols;
int cnt = 0;
double *myArr = (double*)malloc((n - 1) * (m - 1) * sizeof(double));
for(i = 0; i < n; i++){
for(j = 0; j < m; j++){
if(i != x && j != y){
myArr[cnt] = Matrix_get(temp,i,j);
cnt++;
}
}
}
cnt = 0;
for(i = 0; i < n - 1; i++){
for(j = 0; j < m - 1; j++){
Matrix_set(newmat,i,j,myArr[cnt]);
cnt++;
}
}
return newmat;
}
Matrix *Matrix_inverse(Matrix *mat){
double det=Matrix_determinant(mat);
if(mat->rows != mat->cols || det == 0.0){
return Matrix_create(mat->rows, mat->cols);
}
Matrix *temp = Matrix_clone(mat);
int n = temp->rows;
int m = temp->cols;
int i,j;
double tempdet,val;
Matrix *Cofactor = Matrix_create(n, m);
for(j = 0; j < m; j++){
for(i = 0; i < n; i++){
Matrix *Mintemp = Matrix_minor(temp,i, j);
tempdet = Matrix_determinant(Mintemp);
Matrix_set(Cofactor,i,j,tempdet);
}
}
Cofactor = Matrix_transpose(Cofactor);
for(i = 0; i < n; i++){
for(j = 0; j < m; j++){
val=Matrix_get(Cofactor,i,j) * pow(-1.0,(i+j)) /det;
if(isnan(val)) val=0;
Matrix_set(Cofactor,i,j, val);
//Cofactor.setValue(i, j, (Cofactor.getValue(i, j) * Math.pow(-1D, i + j + 2)) / det);
}
}
return Cofactor;
}
Matrix *Matrix_echelon(Matrix* m){
int cols=m->cols;
int rows=m->rows;
int i=0,j=0,k=0;
Matrix *temp=Matrix_clone(m);
double pivot;
for (i=0;i<rows;i++){
for(j = i + 1;j<rows;j++){
pivot = -1*Matrix_get(temp,j,i) / Matrix_get(temp,i,i);
for(k = 0; k < cols; k++){
Matrix_set(temp,j,k, Matrix_get(temp,i,k) * pivot + Matrix_get(temp,j,k));
}
}
}
return(temp);
}
