added test cases and special case of starting point coinsiding with optics element

Ignore-this: ad4d37134d562280bf9293a14935c585

darcs-hash:20110413222248-067c0-90b83cde89a90fc65c0f6b129d637838734f0195

2 files changed, 56 insertions, 0 deletions

diff --git a/gbeam_propagation.m b/gbeam_propagation.m
index 524d4ae..cd7c47c 100644
--- a/gbeam_propagation.m
+++ b/gbeam_propagation.m
@@ -26,8 +26,16 @@ function q = gbeam_propagation(x_pos, q_in, x_in,  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;
+			% there is a tricky case: if position of any optics element coincides
+			% with x_in i.e it is 0 in backwards x coordinates (or at index 1) then
+			% we need to apply abcd matrix of that element in advance.
+			if ( optics_elements_backw{i}.x == 0) 
+				q_in_backw(1)  = q_afteer_element( q_in_backw(1), optics_elements_backw{i}.abcd);
+			end
+
 		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);
@@ -39,3 +47,27 @@ function q = gbeam_propagation(x_pos, q_in, x_in,  optics_elements)
 
 endfunction
 
+%!test 
+%! lambda= 1.064E-6 ;
+%! f1=0.1526;
+%! lns1.abcd=abcd_lens( f1) ;
+%! lns1.x= 0.2;
+%! f2=0.019;
+%! lns2.abcd=abcd_lens( f2) ;
+%! lns2.x= lns1.x+ f1 + f2;
+%! lns3.abcd=abcd_lens( 0.0629) ;
+%! lns3.x= 0.500;
+%! q0=-1.5260e-01 + 1.7310e-04i;
+%! x0=0.2;
+%! optics={lns1,lns2,lns3};
+%! x=[0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7];
+%! q0=1.8098e-96 + 1.3453e+02i;
+%! x0=0;
+%! q_test = gbeam_propagation(x,q0,x0,optics);
+%! 
+%! % test beam is the same but starting point is taken midway 
+%! % and coincides with optics element{1}.x since (x(3) = 0.2)
+%! q=gbeam_propagation(x,q_test(3),x(3),optics);
+%! assert(q,q_test, -1e-6)
+
+
diff --git a/gbeam_propagation_froward_only.m b/gbeam_propagation_froward_only.m
index ba8c1cf..612d30f 100644
--- a/gbeam_propagation_froward_only.m
+++ b/gbeam_propagation_froward_only.m
@@ -2,6 +2,9 @@ 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
+% Note!: if optics element position coinside with a x_pos at some place
+%   the reported value will be the one calculated after the element
+%   so the resulting value will coinside with submitted q_in
 %
 % all x_pos must be to the right of x_in
 % x_pos must be monotonic!
@@ -38,3 +41,24 @@ function q = gbeam_propagation_froward_only(x_pos, q_in, x_in,  optics_elements)
 		q(i)=q_last_calc;
 	endfor
 end
+
+%!test 
+%! lambda= 1.064E-6 ;
+%! f1=0.1526;
+%! lns1.abcd=abcd_lens( f1) ;
+%! lns1.x= 0.2;
+%! f2=0.019;
+%! lns2.abcd=abcd_lens( f2) ;
+%! lns2.x= lns1.x+ f1 + f2;
+%! lns3.abcd=abcd_lens( 0.0629) ;
+%! lns3.x= 0.500;
+%! q0=1.8098e-96 + 1.3453e+02i;
+%! x0=0;
+%! optics={lns1,lns2,lns3};
+%! x=[0, 0.1, 0.2, 0.3, 0,4,  0.5, 0.6, 0.7];
+%! q_test = [1.8098e-96 + 1.3453e+02i,  1.0000e-01 + 1.3453e+02i,  -1.5260e-01 + 1.7310e-04i, -5.2600e-02 + 1.7310e-04i,  -5.2600e-02 + 1.7310e-04i,  3.4371e+00 + 1.8961e-03i, 3.4371e+00 + 1.8961e-03i,  3.4371e+00 + 1.8961e-03i,  3.4371e+00 + 1.8961e-03i];
+%! 
+%! q=gbeam_propagation(x,q0,x0,optics);
+%! assert(q,q_test, -1e-4)
+
+