# CORDIC Implementations

From <https://github.com/suyashmahar/cordic-algorithm-python>

    circular = 1
    linear = 0
    hyperbolic = -1

    def ROM_lookup(iteration, coord_mode):
        if (coord_mode == circular):
            return math.degrees(math.atan(2**(-1*iteration)))
        elif (coord_mode == linear):
            return 2**(-1*iteration)
        elif (coord_mode == hyperbolic):
            return (math.atanh(2**(-1*iteration)))

    def rotation_mode(x, y, z, coord_mode, iterations):
        a = 0.607252935;   # = 1/K
        
        x_val_list = []
        y_val_list = []
        z_val_list = []
        iterations_list = []

        i = 0;                  # Keeps count on number of iterations
        
        current_x = x         # Value of X on ith iteration 
        current_y = y         # Value of Y on ith iteration
        current_z = z         # Value of Z on ith iteration
        
        di = 0
        
        if (coord_mode == hyperbolic):
            i = 1
        else:
            i = 0
            
        flag = 0
        
        if (iterations > 0):
            while (i < iterations):
                if (current_z < 0):
                    di = -1
                else:
                    di = +1
                next_z = current_z - di * ROM_lookup(i, coord_mode)
                next_x = current_x - coord_mode * di * current_y * (2**(-1*i))
                next_y = current_y + di * current_x * 2**(-1*i)
                
                current_x = next_x
                current_y = next_y
                current_z = next_z

                x_val_list.append(current_x)
                y_val_list.append(current_y)
                z_val_list.append(current_z)
                
                iterations_list.append(i)
                
                if (coord_mode == hyperbolic):
                    if ((i != 4) & (i != 13) & (i!=40)):
                        i = i+1
                    elif (flag == 0):
                        flag = 1
                    elif (flag == 1):
                        flag = 0
                        i = i+1
                else:
                    i = i+1
        return { 'x':x_val_list, 'y':y_val_list, 'z':z_val_list,
                 'iteration':iterations_list, }

    def vector_mode(x, y, z, coord_mode, iterations):
        a = 1.2075;   # = 1/K
        
        x_val_list = []
        y_val_list = []
        z_val_list = []
        iterations_list = []

        i = 0;                  # Keeps count on number of iterations
        
        current_x = x         # Value of X on ith iteration 
        current_y = y         # Value of Y on ith iteration
        current_z = z         # Value of Z on ith iteration
        
        di = 0
        
        # This is neccesary since result for i=0 doesn't exists for hyperbolic 
        # co-ordinate system.
        if (coord_mode == hyperbolic):
            i = 1
        else:
            i = 0
            
        flag = 0
        
        if (iterations > 0):
            while (i < iterations):
                di = -1*math.copysign(1, current_y);#*current_x);
                next_x = current_x - coord_mode * di * current_y * (2**(-1*i))
                next_y = current_y + di * current_x * 2**(-1*i)
                next_z = current_z - di * ROM_lookup(i, coord_mode)
                
                current_x = next_x
                current_y = next_y
                current_z = next_z

                x_val_list.append(current_x)
                y_val_list.append(current_y)
                z_val_list.append(current_z)
                
                iterations_list.append(i)
                
                if (coord_mode == hyperbolic):
                    if ((i != 4) & (i != 13) & (i!=40)):
                        i = i+1
                    elif (flag == 0):
                        flag = 1
                    elif (flag == 1):
                        flag = 0
                        i = i+1
                else:
                    i = i+1
        return { 'x':x_val_list, 'y':y_val_list, 'z':z_val_list,
                 'iteration':iterations_list }