How to take derivative of log loss function in gradient descent?

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I know the gradient descent about $z=wx+b$. But how to implement the derivative values of $w$ and $b$ in Python? I see some example like



derivative_weight = (np.dot(x_train, ((y_head-y_train).T))) / x_train.shape[1]  
derivative_bias = np.sum(y_head-y_train) / x_train.shape[1]


In mathematics is



$frac{partial J}{partial w}=frac{1}{m}x(y_{head}-y)^T$
$frac{partial J}{partial b}=frac{1}{m}sum_{i=1}^{m}(y_{head}-y)$



How to get it? How are those formulas derived? Please feel free to help me. Thank you very much.










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  • $begingroup$
    It might be worth editing a formula for $J$ into the question as well.
    $endgroup$
    – J.G.
    Jan 16 at 8:25
















0












$begingroup$


I know the gradient descent about $z=wx+b$. But how to implement the derivative values of $w$ and $b$ in Python? I see some example like



derivative_weight = (np.dot(x_train, ((y_head-y_train).T))) / x_train.shape[1]  
derivative_bias = np.sum(y_head-y_train) / x_train.shape[1]


In mathematics is



$frac{partial J}{partial w}=frac{1}{m}x(y_{head}-y)^T$
$frac{partial J}{partial b}=frac{1}{m}sum_{i=1}^{m}(y_{head}-y)$



How to get it? How are those formulas derived? Please feel free to help me. Thank you very much.










share|cite|improve this question











$endgroup$












  • $begingroup$
    It might be worth editing a formula for $J$ into the question as well.
    $endgroup$
    – J.G.
    Jan 16 at 8:25














0












0








0





$begingroup$


I know the gradient descent about $z=wx+b$. But how to implement the derivative values of $w$ and $b$ in Python? I see some example like



derivative_weight = (np.dot(x_train, ((y_head-y_train).T))) / x_train.shape[1]  
derivative_bias = np.sum(y_head-y_train) / x_train.shape[1]


In mathematics is



$frac{partial J}{partial w}=frac{1}{m}x(y_{head}-y)^T$
$frac{partial J}{partial b}=frac{1}{m}sum_{i=1}^{m}(y_{head}-y)$



How to get it? How are those formulas derived? Please feel free to help me. Thank you very much.










share|cite|improve this question











$endgroup$




I know the gradient descent about $z=wx+b$. But how to implement the derivative values of $w$ and $b$ in Python? I see some example like



derivative_weight = (np.dot(x_train, ((y_head-y_train).T))) / x_train.shape[1]  
derivative_bias = np.sum(y_head-y_train) / x_train.shape[1]


In mathematics is



$frac{partial J}{partial w}=frac{1}{m}x(y_{head}-y)^T$
$frac{partial J}{partial b}=frac{1}{m}sum_{i=1}^{m}(y_{head}-y)$



How to get it? How are those formulas derived? Please feel free to help me. Thank you very much.







derivatives machine-learning numerical-optimization gradient-descent python






share|cite|improve this question















share|cite|improve this question













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share|cite|improve this question








edited Jan 16 at 8:36









Rodrigo de Azevedo

12.9k41857




12.9k41857










asked Jan 16 at 8:19









HoniHoni

12




12












  • $begingroup$
    It might be worth editing a formula for $J$ into the question as well.
    $endgroup$
    – J.G.
    Jan 16 at 8:25


















  • $begingroup$
    It might be worth editing a formula for $J$ into the question as well.
    $endgroup$
    – J.G.
    Jan 16 at 8:25
















$begingroup$
It might be worth editing a formula for $J$ into the question as well.
$endgroup$
– J.G.
Jan 16 at 8:25




$begingroup$
It might be worth editing a formula for $J$ into the question as well.
$endgroup$
– J.G.
Jan 16 at 8:25










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