reorganized file structure

strut/Newton.m

@@ -0,0 +1,61 @@
+function x=newton(Fs,FPs,P0,y,P,TOL);
+ % NEWTON-RAPHSON ALGORITHM 2.3               
+ %
+ % To find a solution to f(x) = 0 given an
+ % initial approximation p0:
+ %
+ % y,P can be used for additional info if the function
+ % requires it.
+ %
+ % Initially written by Burden and Faires, revised by 
+ % B.A. Broughton, 10/01/1999
+ %
+ % INPUT:   initial approximation p0; tolerance TOL;
+ %          maximum number of iterations NO.
+ %
+ % OUTPUT:  approximate solution p or a message of failure
+
+ TRUE = 1;
+ FALSE = 0;
+ F = inline(Fs,'x','P','y');
+ FP = inline(FPs,'x','P');
+ NO=150; 
+ OUP = 1;
+ F0 = F(P0,P,y);
+ % STEP 1
+ I = 1;
+ OK = TRUE;        
+% STEP 2
+ while I <= NO & OK == TRUE   
+        % STEP 3
+        % compute P(I)
+         FP0 = FP(P0,P);
+         D = F0/FP0;
+        % STEP 6
+         P0 = P0 - D;  
+         F0 = F(P0,P,y);
+        % STEP 4
+         if abs(D) < TOL 
+                % procedure completed successfully
+                % fprintf(OUP,'\nApproximate solution = %.10e\n',P0);
+                % fprintf(OUP,'with F(P) = %.10e\n',F0);
+                % fprintf(OUP,'Number of iterations = %d\n',I);
+                % fprintf(OUP,'Tolerance = %.10e\n',TOL);
+                 OK = FALSE;
+        % STEP 5
+         else
+                I = I+1;
+         end
+ end
+ if OK == TRUE 
+% STEP 7
+% procedure completed unsuccessfully
+         fprintf(OUP,'\nIteration number %d',NO);
+         fprintf(OUP,' gave approximation %.10e\n',P0);
+         fprintf(OUP,'with F(P) = %.10e not within tolerance  %.10e\n',F0,TOL);
+ end
+ x = P0;
+
+ 
+
+