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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 import of the tensorflow library
Step1:  Config Contants
in the variable "a" we are going to assign a constant with the initial value of "2"
Step2:  in the variable "b" we are going to assign a constant with the initial value of "5"
Step3:  In the following variable "operation" we will define a sum by applying "add". As a parameter we will use the constants defined above. "a" and "b"
Constants - Sum
Step4:  link documentacion oficial - add
After the definitions of the constants and the operation for this example, we are going to start a session in tensorflow. Then calling the "run" method we executing the operation in the tensorflow graph
Step5:  Constants - Subtraction
Step6:  link documentacion oficial - subtract
with tf.Session() as ses
Step7:  official documentation
Step8:  tf.negative
Step9:  official documentation
Step10:  tf.sign
Step11:  official documentation
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Python Code:
import tensorflow as tf
# check tf version
print(tf.__version__)
Explanation: import of the tensorflow library: essential to start the interaction with tensorflow
End of explanation
a = tf.constant(2)
Explanation: Config Contants
in the variable "a" we are going to assign a constant with the initial value of "2"
End of explanation
b = tf.constant(5)
Explanation: in the variable "b" we are going to assign a constant with the initial value of "5"
End of explanation
operation = tf.add(a, b, name='cons_add')
Explanation: In the following variable "operation" we will define a sum by applying "add". As a parameter we will use the constants defined above. "a" and "b"
Constants - Sum
End of explanation
with tf.Session() as ses:
    print ses.run(operation)
Explanation: link documentacion oficial - add
After the definitions of the constants and the operation for this example, we are going to start a session in tensorflow. Then calling the "run" method we executing the operation in the tensorflow graph
End of explanation
sub_operation = tf.subtract(a, b, name='cons_subtraction')
Explanation: Constants - Subtraction
End of explanation
x = tf.constant([[-1.37 + 2.57j], [-3.37 + 5.33j]])
abs_function = tf.abs(x)
Explanation: link documentacion oficial - subtract
with tf.Session() as ses:
    print ses.run(sub_operation)
Simple Math Function - tf.abs
End of explanation
with tf.Session() as ses:
    print ses.run(abs_function)
Explanation: official documentation
End of explanation
pos_tensor = tf.constant([[5],[7]])
negative_function = tf.negative(pos_tensor)
Explanation: tf.negative
End of explanation
with tf.Session() as ses:
    print ses.run(negative_function)
Explanation: official documentation
End of explanation
sign_tensor = tf.constant([[5]])
sign_function = tf.sign(sign_tensor)
Explanation: tf.sign
End of explanation
with tf.Session() as ses:
    print ses.run(sign_function)
Explanation: official documentation
End of explanation
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