Addressing issue #59 magnitude and phase function for Matlab

mhkit/tests/Utils_TestGenUtils.m

@@ -43,6 +43,34 @@ function test_excel_to_datetime(testCase)
             % check if answer is correct
             assertEqual(testCase,answer,time);
         end
+
+        function test_magnitude_phase(testCase)
+            % 2-d function
+            magnitude = 9;
+            y = sqrt(1/2*magnitude^2); x=y;
+            phase = atan2(y,x);
+            [mag, theta] = magnitude_phase({x; y});
+            assert(all(magnitude == mag))
+            assert(all(phase == theta))
+            xx = [x,x]; yy = [y,y];
+            [mag, theta] = magnitude_phase({xx; yy});
+            assert(all(magnitude == mag))
+            assert(all(phase == theta))
+            % 3-d function
+            magnitude = 9;
+            y = sqrt(1/3*magnitude^2); x=y; z=y;
+            phase1 = atan2(y,x);
+            phase2 = atan2(sqrt(x.^2 + y.^2),z);
+            [mag, theta, phi] = magnitude_phase({x; y; z});
+            assert(all(magnitude == mag))
+            assert(all(phase1 == theta))
+            assert(all(phase2 == phi))
+            xx = [x,x]; yy = [y,y]; zz = [z,z];
+            [mag, theta, phi] = magnitude_phase({xx; yy; zz});
+            assert(all(magnitude == mag))
+            assert(all(phase1 == theta))
+            assert(all(phase2 == phi))
+        end
     end
 end  
 

mhkit/utils/magnitude_phase.m

@@ -0,0 +1,78 @@
+function varargout=magnitude_phase(vector)
+
+%%%%%%%%%%%%%%%%%%%%
+%     Calculates magnitude and phase in two or three dimensions
+%     call -> [mag, theta] = magnitude_phase({x; y})
+%     call -> [mag, theta, phi] = magnitude_phase({x; y; z})
+%     
+% Parameters
+% ------------
+%     vector: cell array  
+%           cell array consisting of x, y, and optionally the z component
+%           of vector
+%       x: array_like x component
+%       y: array like y component
+%       z: array like z component defined positive up (Optional)
+%     
+%% Returns
+% ---------
+%     varargout: array 
+%         depending on number of inputs it will either output an array for    
+%         magnitude and theta or one for magnitude, theta, and phi 
+%           magnitude: array - magnitude of vector
+%           theta: array - radians from the x axis
+%           phi: array - radians from the z-axis defined as positive up
+%        
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+arguments
+    vector;    
+end
+
+% check to see if the input argument is a cell array
+if any(~isa(vector, 'cell'))
+    ME = MException('MATLAB:magnitude_phase','data must be a cell array ex: {x; y; z}');
+    throw(ME);
+end
+
+% check how many inputs were given (if not equal to 2 or 3 throw error)
+n_output = length(vector);
+if n_output ~= 2 && n_output ~= 3
+    ME = MException('MATLAB:magnitude_phase','cell array can only be length 2 or 3');
+    throw(ME);
+end
+
+% make sure number of output variables matches input
+if n_output ~= nargout
+    ME = MException('MATLAB:magnitude_phase',"Number of output variables doesn't match input format (3 output requested for 2d or 2 output requested for 3d)");
+    throw(ME);
+end
+
+% Assign cells to arrays
+x = vector{1,:};
+y = vector{2,:};
+three_d = false;
+if n_output == 3
+    z = vector{3,:};
+    three_d = true;
+end
+
+if three_d
+    if ~isequal(length(x),length(y),length(z))
+        ME = MException('MATLAB:magnitude_phase','length of x, y, and z must be equal');
+        throw(ME);
+    end
+    mag = sqrt(x.^2 + y.^2 + z.^2);
+    theta = atan2(y,x);
+    phi = atan2(sqrt(x.^2 + y.^2),z);
+    varargout{1} = mag; varargout{2} = theta; varargout{3} = phi;
+else
+    if ~isequal(length(x),length(y))
+        ME = MException('MATLAB:magnitude_phase','length of x, and y must be equal');
+        throw(ME);
+    end
+    mag = sqrt(x.^2 + y.^2);
+    theta = atan2(y,x);
+    varargout{1} = mag; varargout{2} = theta;
+end
+
+