Debut Tests ASIFT + Essai VISP simplifié

ASIFT_tests/demo_ASIFT_src/numerics1.cpp

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+// Authors: Unknown. Please, if you are the author of this file, or if you 
+// know who are the authors of this file, let us know, so we can give the 
+// adequate credits and/or get the adequate authorizations.
+
+
+#include "numerics1.h"
+
+float **allocate_float_matrix(int nrows, int ncols)
+{
+	float ** matrix;
+	matrix = new float*[nrows];
+	for(int i=0; i < nrows; i++) matrix[i] = new float[ncols];
+	return matrix;
+}
+
+
+void desallocate_float_matrix(float **matrix, int nrows, int ncols)
+{
+	if (matrix == NULL) return;
+
+	for(int i=0; i < nrows; i++) { delete[] matrix[i]; matrix[i] = 0;}
+	matrix = 0;
+	
+	ncols = ncols; // to remove the warning unused parameter ¡®ncols¡¯
+}
+
+
+// **********************************************
+//  LU based algorithms
+// **********************************************
+
+
+
+// Solves Ax=b by using lu decomposition 
+int lusolve(float **a, float *x, float *b, int n)
+{
+
+	float d;
+	int *indx = new int[n];
+
+	if (ludcmp(a,n,indx,&d))
+	{
+
+		for(int i=0; i < n; i++) x[i] = b[i];
+		lubksb(a,n,indx,x);
+		
+		delete[] indx; /*memcheck*/
+		return 1;
+	} else
+	{
+
+		printf("lusolve::lu decomposition failed\n");
+		delete[] indx; /*memcheck*/
+		return 0;
+	}	
+	delete[] indx; // Guoshen Yu
+}
+
+
+
+int ludcmp(float **a, int n, int *indx, float *d)
+{
+
+	int i,imax=0,j,k,aux;
+	float big,dum,sum,temp;
+	float *vv;
+
+
+	vv=(float *) malloc(n*sizeof(float));
+	*d=1.0;
+
+
+	for(i=0;i<n;i++) indx[i]=i;
+
+
+	/**** Look for the largest value of every line and store 1/this value****/
+	for(i=0;i<n;i++){
+
+		big=0.0;
+		for(j=0;j<n;j++) 
+			if ( (temp=fabs(a[i][j]))>big ) big=temp;
+
+			if (big==0.0) { return 0; printf("LU Decomposition failed\n");}
+			
+		vv[i]=1.0/big;
+	}
+
+
+  
+
+	for(j=0;j<n;j++){
+
+		for(i=0;i<j;i++){
+      
+			sum=a[i][j];
+			for(k=0;k<i;k++) sum-= a[i][k]*a[k][j];
+			a[i][j]=sum; 
+
+		}
+
+
+		big=0.0;
+		for(i=j;i<n;i++){
+      
+			sum=a[i][j];
+			for(k=0;k<j;k++)   
+				sum -=a[i][k]*a[k][j];
+			a[i][j]=sum;
+
+			if ( (dum=vv[i]*fabs(sum))>=big){
+				big=dum;
+				imax=i;
+			}
+		}
+
+    
+		if (j != imax){
+
+			for(k=0;k<n;k++){
+
+				dum=a[imax][k];
+				a[imax][k]=a[j][k];
+				a[j][k]=dum;
+			}
+
+			*d=-(*d);
+			vv[imax]=vv[j];
+
+			aux=indx[j];
+			indx[j]=indx[imax];
+			indx[imax]=aux;
+		}
+
+		if (a[j][j]==0.0)  a[j][j]=NRTINY;
+    
+
+		if (j!=n-1 ){
+
+			dum=1.0 / a[j][j];
+			for(i=j+1;i<n;i++) a[i][j]*=dum;
+		}
+    
+
+	}
+
+	free(vv);
+	return 1;
+}
+
+
+
+/* Solves the set of n linear equations Ax=b. Here a[0..n-1][0..n-1] as input, not as the matrix A but rather as its LU decomposition,*/
+/* determined by the routine ludcmp. indx[0..n-1] is input as the permutation vector returned by ludcmp. b[0..n-1] is input as the    */
+/* right hand side vector and returns with the solution vector x. */
+void lubksb(float **a, int n, int *indx, float *b)
+{
+
+	int i,ii=0,j;
+	float sum,*aux;
+
+	aux= (float *) malloc(n*sizeof(float));
+	
+	
+	for(i=0;i<n;i++)
+		aux[i]=b[indx[i]];
+
+
+	for(i=0;i<n;i++){
+		sum=aux[i];
+
+		if (ii)
+			for(j=ii-1;j<i;j++) sum-=a[i][j]*aux[j];
+		else if (sum) ii=i+1;
+		aux[i]=sum;
+	}
+
+	for(i=n-1;i>=0;i--){
+		sum=aux[i];
+		for(j=i+1;j<n;j++) sum-=a[i][j]*aux[j];
+		aux[i]=sum/a[i][i];
+		b[i]=sum/a[i][i];
+	}
+
+	free(aux);
+}