How one epoch completes in Perceptron?
We changed value on 2nd row, now we have new weight values and bias value, do we need to check the third row which is 1  0  1 with new weight and bias value or with old one which is (w1=0, w2=0, b=1) ?


The Perceptron processes one example at a time. The weights are immediately applied and subsequently updated (if the prediction is not correct).


  if we check 2nd row 3rd row and 4th row with new values and it satisfy 2nd 3rd and 4th row with new value, does this complete our 1st epoch?


Applying the learning rule to each example in the training set is called an
epoch.

Finishing an epoch doesn't mean that the perceptron converges to zero training error (it's typical to run multiple epochs).

For example, given:

(X1)--\
       \
        \ W1
         \
(X2)--W2--+-Y---O
         /
        / B
       /
 (1)--/


with:

$$Y = W_1 \cdot X_1 + W_2 \cdot X_2 + B$$

$$
O = \begin{cases}
0 &amp; \text{if $Y \le 0$} \\
1 &amp; \text{if $Y &gt; 0$}
\end{cases}
$$

$$\delta = Target - O$$

$$\Delta W = \epsilon \cdot \delta \cdot O$$

If $\epsilon = 1$ and $W_1 = W_2 = B = 0$:

X1  X2  Target   W1    W2     B     Y  O  Delta   W1'   W2'     B'
 0   0     0      0     0     0     0  0      0    0     0      0
 0   1     1      0     0     0     0  0      1    0     1      1  &lt;-error
 1   0     1      0     1     1     1  1      0    0     1      1
 1   1     1      0     1     1     2  1      0    0     1      1
--------- END OF EPOCH 1 / NOT CONVERGED ------------------------
 0   0     0      0     1     1     1  1     -1    0     1      0  &lt;-error
 0   1     1      0     1     0     1  1      0    0     1      0
 1   0     1      0     1     0     0  0      1    1     1      1  &lt;-error
 1   1     1      1     1     1     3  1      0    1     1      1
--------- END OF EPOCH 2 / NOT CONVERGED ------------------------
 ...
--------- END OF EPOCH 3 / NOT CONVERGED ------------------------
 ...                                                              NO ERROR
--------- END OF EPOCH 4 / CONVERGED ----------------------------