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












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












$begingroup$


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













share|cite|improve this question




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










0






active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3075460%2fhow-to-take-derivative-of-log-loss-function-in-gradient-descent%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3075460%2fhow-to-take-derivative-of-log-loss-function-in-gradient-descent%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Mario Kart Wii

The Binding of Isaac: Rebirth/Afterbirth

What does “Dominus providebit” mean?