Adding tests for strain functions

strain_to_deformation.m

@@ -0,0 +1,9 @@
+function [ F ] = strain_to_deformation( E )
+%STRAIN_TO_DEFORMATION Construct a deformation tensor from a strain tensor.
+%   F = strain_to_deformation( E ) computes the rotation-free deformation 
+%   tensor F corresponding to the Green-Lagrange strain tensor E. 
+
+    [Q, D] = eig(2*E+eye(size(E)));
+    F = Q*D.^0.5*Q';
+
+end

strain_tensor_to_order_params.m → strain_to_order_params.m

@@ -1,6 +1,6 @@
-function [ strain_order_parameters ] = strain_tensor_to_order_params( E )
-%STRAIN_TENSOR_TO_ORDER_PARAMS Convert a strain tensor to order parameters.
-%   e = strain_tensor_to_order_params( E ) converts a strain tensor E,
+function [ strain_order_parameters ] = strain_to_order_params( E )
+%STRAIN_TO_ORDER_PARAMS Convert a strain tensor to order parameters.
+%   e = strain_to_order_params( E ) converts a strain tensor E,
 %   represented by a 3x3 matrix, to a 6x1 matrix e representing the strain
 %   order parameters. See Phys. Rev. B 90, 224105 (2014) for details.
 

tests/strain_to_deformation_test.m

@@ -0,0 +1,4 @@
+%% Test zero strain
+F = strain_to_deformation(zeros(3));
+expected_F = eye(3);
+assert(all(F == expected_F))

tests/strain_to_order_params_test.m

@@ -0,0 +1,4 @@
+%% Test zero strain
+order_params = strain_to_order_params(zeros(3));
+expected_order_params = zeros(6,1);
+assert(all(order_params == expected_order_params))