beam propagation function renamed and moved to separate files

Ignore-this: 972fa9dce2f57e8ddb1624bab32be1ed

darcs-hash:20110413151028-067c0-a7e6d0c98e2856fdff930d4bf3216056eb937367

4 files changed, 84 insertions, 83 deletions

diff --git a/abcd.m b/abcd.m
index ac9b1db..814615c 100644
--- a/abcd.m
+++ b/abcd.m
@@ -29,87 +29,7 @@ function optics = arrange_optics_along_x(optics_unsorted)
 	end
 end
 
-function q = prop_forward(x_pos, q_in, x_in,  optics_elements)
-% calculate the 'q' parameter of the Gaussian beam propagating through optical
-% 'optics_elements' only in the positive direction  along 'x' axis at points 'x_pos'
-%  takes the gaussian beam with initial q_in parameter at x_in
-%
-% all x_pos must be to the right of x_in
-% x_pos must be monotonic!
-	if (any(x_pos < x_in))
-		error('all beam positions must be to the right of the x_in');
-	end
-
-	optics_elements=arrange_optics_along_x(optics_elements);
-
-	% Forward propagation to the right of x_in
-	Np=length(x_pos); % number of 'x' points
-	Nel=length(optics_elements) ;
-	q=0*x_pos; % q vector initialization
-	q_last_calc=q_in;
-	x_last_calc=x_in; % the furthest calculated point
-	for i=1:Np
-		x_pos_i=x_pos(i);
-		for k=1:length(optics_elements) 
-			% iterates through optics_elements to make sure 
-			% we take them in account for the beam propagation
-			el=optics_elements{k};
-			if ( (x_last_calc < el.x) && (el.x <= x_pos_i) )
-				abcd=abcd_free_space(el.x-x_last_calc);
-				q_last_calc=q_afteer_element(q_last_calc,abcd);
-				q_last_calc=q_afteer_element(q_last_calc,el.abcd);
-				x_last_calc=el.x;
-			endif
-		endfor
-		if (x_pos_i > x_last_calc);
-			abcd=abcd_free_space(x_pos_i-x_last_calc);
-			q_last_calc=q_afteer_element(q_last_calc,abcd);
-			x_last_calc=x_pos_i;
-		endif
-		q(i)=q_last_calc;
-	endfor
-end
-
-function q = prop(x_pos, q_in, x_in,  optics_elements)
-% calculate the 'q' parameter of the Gaussian beam propagating through optical
-% 'optics_elements' array along 'x' axis at points 'x_pos'
-%  takes the gaussian beam with initial q_in parameter at x_in
-% x_pos must be monotonic!
-
-	q=0*x_pos; % q vector initialization
 
-	if any(x_pos >= x_in)
-		% Forward propagation to the right of x_in
-		q(x_pos >= x_in) = prop_forward(x_pos(x_pos>=x_in), q_in, x_in,  optics_elements);
-	end
-
-	if any(x_pos < x_in)
-		% Backward propagation part the left of x_in
-		% do it as forward propagation of the reverse beam
-		x_backw=x_pos(x_pos<x_in);
-		% now let's reflect the beam with respect to x_in
-		% and solve the problem as forward propagating.
-		x_backw=x_in-x_backw;
-		% now we need to flip x positions
-		x_backw=fliplr(x_backw);
-		% reflected beam means inverted radius of curvature or real part of q parameter
-		q_in_backw = -real(q_in) + 1i*imag(q_in);
-		optics_elements_backw=optics_elements;
-		% we need to flip all optics elements around x_in as well
-		for i=1:length(optics_elements_backw)
-			optics_elements_backw{i}.x=x_in-optics_elements_backw{i}.x;
-		end
-
-		q_backw = prop_forward(x_backw, q_in_backw, 0,  optics_elements_backw);
-		% now we need to flip the radius of curvature again
-		q_backw =  -real(q_backw) + 1i*imag(q_backw);
-
-		% final assignment of the backwards propagating beam 
-		% which we need to flip back
-		q(x_pos<x_in) = fliplr(q_backw);
-	end
-
-endfunction
 
 function waste =q2waste(q, lambda)
 	for i=1:size(q,2)
diff --git a/gbeam_propagation.m b/gbeam_propagation.m
new file mode 100644
index 0000000..524d4ae
--- /dev/null
+++ b/gbeam_propagation.m
@@ -0,0 +1,41 @@
+function q = gbeam_propagation(x_pos, q_in, x_in,  optics_elements)
+% calculate the 'q' parameter of the Gaussian beam propagating through optical
+% 'optics_elements' array along 'x' axis at points 'x_pos'
+%  takes the gaussian beam with initial q_in parameter at x_in
+% x_pos must be monotonic!
+
+	q=0*x_pos; % q vector initialization
+
+	if any(x_pos >= x_in)
+		% Forward propagation to the right of x_in
+		q(x_pos >= x_in) = gbeam_propagation_froward_only(x_pos(x_pos>=x_in), q_in, x_in,  optics_elements);
+	end
+
+	if any(x_pos < x_in)
+		% Backward propagation part the left of x_in
+		% do it as forward propagation of the reverse beam
+		x_backw=x_pos(x_pos<x_in);
+		% now let's reflect the beam with respect to x_in
+		% and solve the problem as forward propagating.
+		x_backw=x_in-x_backw;
+		% now we need to flip x positions
+		x_backw=fliplr(x_backw);
+		% reflected beam means inverted radius of curvature or real part of q parameter
+		q_in_backw = -real(q_in) + 1i*imag(q_in);
+		optics_elements_backw=optics_elements;
+		% we need to flip all optics elements around x_in as well
+		for i=1:length(optics_elements_backw)
+			optics_elements_backw{i}.x=x_in-optics_elements_backw{i}.x;
+		end
+
+		q_backw = gbeam_propagation_froward_only(x_backw, q_in_backw, 0,  optics_elements_backw);
+		% now we need to flip the radius of curvature again
+		q_backw =  -real(q_backw) + 1i*imag(q_backw);
+
+		% final assignment of the backwards propagating beam 
+		% which we need to flip back
+		q(x_pos<x_in) = fliplr(q_backw);
+	end
+
+endfunction
+
diff --git a/gbeam_propagation_froward_only.m b/gbeam_propagation_froward_only.m
new file mode 100644
index 0000000..ba8c1cf
--- /dev/null
+++ b/gbeam_propagation_froward_only.m
@@ -0,0 +1,40 @@
+function q = gbeam_propagation_froward_only(x_pos, q_in, x_in,  optics_elements)
+% calculate the 'q' parameter of the Gaussian beam propagating through optical
+% 'optics_elements' only in the positive direction  along 'x' axis at points 'x_pos'
+% takes the gaussian beam with initial q_in parameter at x_in
+%
+% all x_pos must be to the right of x_in
+% x_pos must be monotonic!
+	if (any(x_pos < x_in))
+		error('all beam positions must be to the right of the x_in');
+	end
+
+	optics_elements=arrange_optics_along_x(optics_elements);
+
+	% Forward propagation to the right of x_in
+	Np=length(x_pos); % number of 'x' points
+	Nel=length(optics_elements) ;
+	q=0*x_pos; % q vector initialization
+	q_last_calc=q_in;
+	x_last_calc=x_in; % the furthest calculated point
+	for i=1:Np
+		x_pos_i=x_pos(i);
+		for k=1:length(optics_elements) 
+			% iterates through optics_elements to make sure 
+			% we take them in account for the beam propagation
+			el=optics_elements{k};
+			if ( (x_last_calc < el.x) && (el.x <= x_pos_i) )
+				abcd=abcd_free_space(el.x-x_last_calc);
+				q_last_calc=q_afteer_element(q_last_calc,abcd);
+				q_last_calc=q_afteer_element(q_last_calc,el.abcd);
+				x_last_calc=el.x;
+			endif
+		endfor
+		if (x_pos_i > x_last_calc);
+			abcd=abcd_free_space(x_pos_i-x_last_calc);
+			q_last_calc=q_afteer_element(q_last_calc,abcd);
+			x_last_calc=x_pos_i;
+		endif
+		q(i)=q_last_calc;
+	endfor
+end
diff --git a/propagation.m b/propagation.m
index 35547f5..15d52c2 100644
--- a/propagation.m
+++ b/propagation.m
@@ -23,7 +23,7 @@ optics={lns1,lns2,lns3};
 
 x=0:.001:Ltot;
 printf('======== Forward propagation ======\n')
-q1=prop(x,q0,0,optics);
+q1=gbeam_propagation(x,q0,0,optics);
 w1=q2waste(q1, lambda);
 r1=q2radius(q1,lambda);
 
@@ -32,7 +32,7 @@ printf('======== Backward propagation ===\n')
 rf=-rf;
 q1b=waste_r2q(wf,rf,lambda);
 
-q2b=prop(x,q1b,Ltot,optics);
+q2b=gbeam_propagation(x,q1b,Ltot,optics);
 printf('=================================\n')
 wb=q2waste(q2b, lambda);
 rb=q2radius(q2b,lambda);
@@ -48,7 +48,7 @@ r0
 wf
 rf
 q0=waste_r2q(w0,r0,lambda);
-qtf=prop(Ltot, q0,0, optics);
+qtf=gbeam_propagation(Ltot, q0,0, optics);
 printf('values below should match wf and rf: \n')
 waste = q2waste(qtf, lambda)
 radius = q2radius(qtf,lambda)