bugfix by Yohann

Signed-off-by: Wolfgang Ludwig <wolfgang.ludwig@esrf.fr>

zUtil_Maths/gtMathsRod2Euler.m

-function euler = gtMathsRod2Euler(r)
-% GTMATHSROD2EULER  Convert Rodrigues vectors to Euler angles (in degrees).
-%                   These follow Bunge convention (ZXZ) [phi1; phi; phi2].
-%
-%     euler = gtMathsRod2Euler(r)
-%     -------------------------------------------------------------------------
-%
-%     INPUT:
-%       r     = <double>  Rodrigues vectors, as column vectors (3xN array).
-%
-%     OUTPUT:
-%       euler = <double>  Euler angles triplets, as column vectors (3xN array).
-%                         Output angles are in degrees and only positive.
-%
-%     Version 002 17-10-2012 by YGuilhem
-%       Vectorize function to process quickly lots of Rogrigues vectors
-%
-%     Version 001 15-06-2012 by YGuilhem
-
-% Check size of r column vectors
-if size(r, 1) ~= 3
-    gtError('Rodrigues:wrong_input_size', ... 
-        'Input array r should be sized 3xN!');
-end
-
-% Set epsilon to avoid singular values
-epsilon = 1.e-9;
-
-% Build regular filters
-regular = r >= epsilon;
-regular_a = regular(1, :) & regular(2, :);
-regular_b = regular(3, :);
-
-% conpute intermediate values
-a = double(~regular_a).*pi/4 + double(regular_a).*atan2(r(2, :), r(1, :));
-b = double(~regular_b).*pi/4 + double(regular_b).*atan(r(3, :));
-
-% Compute Euler angles in radians
-phi1 = a + b;
-phi  = 2*atan2(sqrt(r(1, :).^2 + r(2, :).^2), sqrt(1. + r(3, :).^2));
-phi2 = b - a;
-
-% Switch to degrees
-euler = [phi1 ; phi ; phi2] * 180 / pi;
-
-% Shift to positive angles range
-euler = mod(euler, 360.);
-
-end % end of function
+function euler = gtMathsRod2Euler(r)
+% GTMATHSROD2EULER  Convert Rodrigues vectors to Euler angles (in degrees).
+%                   These follow Bunge convention (ZXZ) [phi1; phi; phi2].
+%
+%     euler = gtMathsRod2Euler(r)
+%     -------------------------------------------------------------------------
+%
+%     INPUT:
+%       r     = <double>  Rodrigues vectors, as column vectors (3xN array).
+%
+%     OUTPUT:
+%       euler = <double>  Euler angles triplets, as column vectors (3xN array).
+%                         Output angles are in degrees and only positive.
+%
+%     Version 002 17-10-2012 by YGuilhem
+%       Vectorize function to process quickly lots of Rogrigues vectors
+%
+%     Version 001 15-06-2012 by YGuilhem
+
+% Check size of r column vectors
+if size(r, 1) ~= 3
+    gtError('Rodrigues:wrong_input_size', ...
+        'Input array r should be sized 3xN!');
+end
+
+% Set epsilon to avoid singular values
+epsilon = 1.e-9;
+
+% Compute first intermediate value
+c = cos(atan(sqrt(sum(r.^2))));
+
+% Build regular filters
+regular = abs(c.*r) >= epsilon;
+regular_a = regular(1, :) | regular(2, :);
+regular_b = regular(3, :) | c >= epsilon;
+
+% Compute second intermediate values
+a = double(~regular_a).*pi/4 + double(regular_a).*atan2(r(2, :), r(1, :));
+b = double(~regular_b).*pi/4 + double(regular_b).*atan2(r(3, :), 1.);
+
+% Compute Euler angles in radians
+phi1 = a + b;
+phi  = 2*atan2(sqrt(r(1, :).^2 + r(2, :).^2), sqrt(1. + r(3, :).^2));
+phi2 = b - a;
+
+% Switch to degrees
+euler = [phi1 ; phi ; phi2] * 180 / pi;
+
+% Shift to positive angles range
+euler = mod(euler, 360.);
+
+end % end of function