# Pointers

Pointers are to be assigned without any * or &

So ptr=&a

& gives the address of data structure

To access the value of data structure from pointer we use *

Declare a pointer as

data_structure_to_which_pointer_will_point *name_of_pointer

http://www.tutorialspoint.com/cplusplus/cpp_null_pointers.htm

http://www.tutorialspoint.com/cplusplus/cpp_passing_pointers_to_functions.htm

http://www.tutorialspoint.com/cplusplus/cpp_array_of_pointers.htm

http://www.tutorialspoint.com/cplusplus/cpp_pointers_vs_arrays.htm

http://www.tutorialspoint.com/cplusplus/cpp_pointer_arithmatic.htm

http://www.tutorialspoint.com/cplusplus/cpp_pointer_to_pointer.htm

http://www.tutorialspoint.com/cplusplus/cpp_return_pointer_from_functions.htm

# Criteria for non linearity

If there are terms like x1 * x2 or sine of x1 or cosine or any trigonometric function

# Difference between ordinary and partial differential equations

In ordinary differential equations we have only one independent variable, i.e an equation where the terms are getting differentiated only with respect to time

In partial differential equations we can have multiple independent variables with respect to which the dependent variables will be differentiated.

# Use of merge_atmop.sh

./merge_atmop.sh \$(seq 1990 1998)

seq startyear endyear gives a sequence of the years on which the script would work.

# Polar Plot in Python

```"""
Demo of a line plot on a polar axis.
"""
import numpy as np
import matplotlib.pyplot as plt

r = np.arange(0, 3.0, 0.01)
theta = 2 * np.pi * r

ax = plt.subplot(111, projection='polar')
ax.plot(theta, r, color='r', linewidth=3)
ax.set_rmax(2.0)
ax.grid(True)

ax.set_title("A line plot on a polar axis", va='bottom')
plt.show()```