[FIXED] tensorflow logistic regression matrix

Issue

hello I'm new to tensorflow and I'm getting a feel for it. so i was given a task to multiply these 4 matrices. i was able to do that but now I'm being asked to Take the (16,4) outputs from the multiplication of the (16,8) and (8,4) and Apply a Logistics function on all outputs. Then multiply this new matrix of shape (16,4) by the (4,2) matrix. Take these (16,2) outputs and apply a Logistics function on them. Now multiply this new (16,2) matrix by the (2,1) matrix. I'm suppose to be able to do all this with matrix manipulation. I'm kind of confused on how to go about it because i only kind of sort of understand linear regression. i know they are similar but i wouldn't know how to apply it. any tips please. no I'm not asking for someone to finish i just would like a better example than what i was given because i can't figure out how to go about a logistic function using a matrix. this is what i have so far

import tensorflow as ts
import numpy as np
import os
# AWESOME SAUCE WARNING MESSAGE WAS GETTING ANNOYING
os.environ['TF_CPP_MIN_LOG_LEVEL']='2' #to avoid warnings about compilation

# for different matrix asked to multiply with
# use random for random numbers in each matrix
m1 = np.random.rand(16,8)
m2 = np.random.rand(8,4)
m3 = np.random.rand(4,2)
m4 = np.random.rand(2,1)


# using matmul to mulitply could use @ or dot() but using tensorflow
c = ts.matmul(m1,m2)
d = ts.matmul(c,m3)
e = ts.matmul(d, m4)

#attempting to create log regression
arf = ts.Variable(m1,name = "ARF")



with ts.Session() as s:
    r1 = s.run(c)
    print("M1 * M2: \n",r1)

    r2 = s.run(d)
    print("Result of C * M3: \n ", r2)

    r3 = s.run(e)
    print("Result of D * M4: \n",r3)

    #learned i cant reshape just that easily
    #r4 = ts.reshape(m1,(16,4))
    #print("Result of New M1: \n", r4)

Solution

I think you have the right idea. The logistic function is just 1 / (1 + exp(-z)) where z is the matrix you want to apply it to. With that in mind you can simply do:

logistic = 1 / (1 + ts.exp(-c))

This will apply the formula element-wise to the input. The result is that this:

    lg = s.run(logistic)
    print("Result of logistic function \n ", lg)

…will print a matrix the same size as c (16,4), where all values are between 0 and 1. You can then go on to the rest of the multiplications the assignment is asking for.

Answered By - Mark