What does it essentially mean if the neural network has convex error surface?












1














Suppose if I am building a Linear Regression model with one fully connected layer and a sigmoid with minimizing mean squared error as objective. I understand that this network has a convex error surface since the functions involved, affine transformation, sigmoid, and objective are convex.



$$y' = sigmoid(W.X + b)$$
Minimize $$ (y - y')^2 $$
where $X$ is input vector,
$y$ is the actual output,
$y'$ is the predicted output and,
$W$ is the parameter matrix.



Since it is a convex surface, we will be able to find a global optimum. However, if the data is not linearly separable, is the global optimum we found is still the best solution? Is it possible to have a better solution with the addition of extra layers and convex or non-convex non-linearity?










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  • This question very much reads lie a "do my homework" post. You are more likely to get useful answers if you edit your question to "Provide details. Share your research."
    – Eric Towers
    Nov 24 at 0:09
















1














Suppose if I am building a Linear Regression model with one fully connected layer and a sigmoid with minimizing mean squared error as objective. I understand that this network has a convex error surface since the functions involved, affine transformation, sigmoid, and objective are convex.



$$y' = sigmoid(W.X + b)$$
Minimize $$ (y - y')^2 $$
where $X$ is input vector,
$y$ is the actual output,
$y'$ is the predicted output and,
$W$ is the parameter matrix.



Since it is a convex surface, we will be able to find a global optimum. However, if the data is not linearly separable, is the global optimum we found is still the best solution? Is it possible to have a better solution with the addition of extra layers and convex or non-convex non-linearity?










share|cite|improve this question
























  • This question very much reads lie a "do my homework" post. You are more likely to get useful answers if you edit your question to "Provide details. Share your research."
    – Eric Towers
    Nov 24 at 0:09














1












1








1


1





Suppose if I am building a Linear Regression model with one fully connected layer and a sigmoid with minimizing mean squared error as objective. I understand that this network has a convex error surface since the functions involved, affine transformation, sigmoid, and objective are convex.



$$y' = sigmoid(W.X + b)$$
Minimize $$ (y - y')^2 $$
where $X$ is input vector,
$y$ is the actual output,
$y'$ is the predicted output and,
$W$ is the parameter matrix.



Since it is a convex surface, we will be able to find a global optimum. However, if the data is not linearly separable, is the global optimum we found is still the best solution? Is it possible to have a better solution with the addition of extra layers and convex or non-convex non-linearity?










share|cite|improve this question















Suppose if I am building a Linear Regression model with one fully connected layer and a sigmoid with minimizing mean squared error as objective. I understand that this network has a convex error surface since the functions involved, affine transformation, sigmoid, and objective are convex.



$$y' = sigmoid(W.X + b)$$
Minimize $$ (y - y')^2 $$
where $X$ is input vector,
$y$ is the actual output,
$y'$ is the predicted output and,
$W$ is the parameter matrix.



Since it is a convex surface, we will be able to find a global optimum. However, if the data is not linearly separable, is the global optimum we found is still the best solution? Is it possible to have a better solution with the addition of extra layers and convex or non-convex non-linearity?







convex-analysis convex-optimization machine-learning linear-regression neural-networks






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 24 at 1:47

























asked Nov 24 at 0:06









backprop7

296




296












  • This question very much reads lie a "do my homework" post. You are more likely to get useful answers if you edit your question to "Provide details. Share your research."
    – Eric Towers
    Nov 24 at 0:09


















  • This question very much reads lie a "do my homework" post. You are more likely to get useful answers if you edit your question to "Provide details. Share your research."
    – Eric Towers
    Nov 24 at 0:09
















This question very much reads lie a "do my homework" post. You are more likely to get useful answers if you edit your question to "Provide details. Share your research."
– Eric Towers
Nov 24 at 0:09




This question very much reads lie a "do my homework" post. You are more likely to get useful answers if you edit your question to "Provide details. Share your research."
– Eric Towers
Nov 24 at 0:09















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