Generalizing the fitting procedure as a linear algebra problem
+
Rewriting the fitting procedure as a linear algebra problem, follows
-We are obviously not limited to the above polynomial. We could replace the various powers of \( x \) with elements of Fourier series, that is, instead of \( x_i^j \) we could have \( \cos{(j x_i)} \) or \( \sin{(j x_i)} \), or time series or other orthogonal functions.
-For every set of values \( y_i,x_i \) we can then generalize the equations to
+Defining the vectors
$$
-\begin{align*}
-y_0&=\beta_0x_{00}+\beta_1x_{01}+\beta_2x_{02}+\dots+\beta_{n-1}x_{0n-1}+\epsilon_0\\
-y_1&=\beta_0x_{10}+\beta_1x_{11}+\beta_2x_{12}+\dots+\beta_{n-1}x_{1n-1}+\epsilon_1\\
-y_2&=\beta_0x_{20}+\beta_1x_{21}+\beta_2x_{22}+\dots+\beta_{n-1}x_{2n-1}+\epsilon_2\\
-\dots & \dots \\
-y_{i}&=\beta_0x_{i0}+\beta_1x_{i1}+\beta_2x_{i2}+\dots+\beta_{n-1}x_{in-1}+\epsilon_i\\
-\dots & \dots \\
-y_{n-1}&=\beta_0x_{n-1,0}+\beta_1x_{n-1,2}+\beta_2x_{n-1,2}+\dots+\beta_1x_{n-1}^{n-1,n-1}+\epsilon_{n-1}.\\
-\end{align*}
+\hat{y} = [y_0,y_1, y_2,\dots, y_{n-1}]^T,
$$
-We redefine in turn the matrix \( \hat{X} \) as
+$$
+\hat{\beta} = [\beta_0,\beta_1, \beta_2,\dots, \beta_{n-1}]^T,
+$$
+
+$$
+\hat{\epsilon} = [\epsilon_0,\epsilon_1, \epsilon_2,\dots, \epsilon_{n-1}]^T,
+$$
+
+and the matrix
$$
\hat{X}=
\begin{bmatrix}
-x_{00}& x_{01} &x_{02}& \dots & \dots &x_{0,n-1}\\
-x_{10}& x_{11} &x_{12}& \dots & \dots &x_{1,n-1}\\
-x_{20}& x_{21}^1 &x_{22}2& \dots & \dots &x_{2,n-1}\\
+1& x_{0}^1 &x_{0}^2& \dots & \dots &x_{0}^{n-1}\\
+1& x_{1}^1 &x_{1}^2& \dots & \dots &x_{1}^{n-1}\\
+1& x_{2}^1 &x_{2}^2& \dots & \dots &x_{2}^{n-1}\\
\dots& \dots &\dots& \dots & \dots &\dots\\
-x_{n-1,00}& x_{n-1,1} &x_{n-1,2}& \dots & \dots &x_{n-1,n-1}\\
+1& x_{n-1}^1 &x_{n-1}^2& \dots & \dots &x_{n-1}^{n-1}\\
\end{bmatrix}
$$
-and without loss of generality we rewrite again our equations as
+we can rewrite our equations as
$$
\hat{y} = \hat{X}\hat{\beta}+\hat{\epsilon}.
$$
-
-The left-hand side of this equation forms know. Our error vector \( \hat{\epsilon} \) and the parameter vector \( \hat{\beta} \) are our unknow quantities. How can we obtain the optimal set of \( \beta_i \) values?
@@ -174,6 +188,10 @@ The left-hand side of this equation forms know. Our error vector \( \hat{\epsilo
Generalizing the fitting procedure as a linear algebra problem
-We have defined the matrix \( \hat{X} \)
+We are obviously not limited to the above polynomial. We could replace the various powers of \( x \) with elements of Fourier series, that is, instead of \( x_i^j \) we could have \( \cos{(j x_i)} \) or \( \sin{(j x_i)} \), or time series or other orthogonal functions.
+For every set of values \( y_i,x_i \) we can then generalize the equations to
$$
\begin{align*}
y_0&=\beta_0x_{00}+\beta_1x_{01}+\beta_2x_{02}+\dots+\beta_{n-1}x_{0n-1}+\epsilon_0\\
y_1&=\beta_0x_{10}+\beta_1x_{11}+\beta_2x_{12}+\dots+\beta_{n-1}x_{1n-1}+\epsilon_1\\
-y_2&=\beta_0x_{20}+\beta_1x_{21}+\beta_2x_{22}+\dots+\beta_{n-1}x_{2n-1}+\epsilon_1\\
+y_2&=\beta_0x_{20}+\beta_1x_{21}+\beta_2x_{22}+\dots+\beta_{n-1}x_{2n-1}+\epsilon_2\\
\dots & \dots \\
-y_{i}&=\beta_0x_{i0}+\beta_1x_{i1}+\beta_2x_{i2}+\dots+\beta_{n-1}x_{in-1}+\epsilon_1\\
+y_{i}&=\beta_0x_{i0}+\beta_1x_{i1}+\beta_2x_{i2}+\dots+\beta_{n-1}x_{in-1}+\epsilon_i\\
\dots & \dots \\
-y_{n-1}&=\beta_0x_{n-1,0}+\beta_1x_{n-1,2}+\beta_2x_{n-1,2}+\dots+\beta_1x_{n-1,n-1}+\epsilon_{n-1}.\\
+y_{n-1}&=\beta_0x_{n-1,0}+\beta_1x_{n-1,2}+\beta_2x_{n-1,2}+\dots+\beta_1x_{n-1}^{n-1,n-1}+\epsilon_{n-1}.\\
\end{align*}
$$
-
-We well use this matrix to define the approximation \( \hat{\tilde{y}} \) via the unknown quantity \( \hat{\beta} \) as
-$$
-\hat{\tilde{y}}= \hat{X}\hat{\beta},
-$$
-
-and in order to find the optimal parameters \( \beta_i \) instead of solving the above linear algebra problem, we define a function which gives a measure of the spread between the values \( y_i \) (which represent hopefully the exact values) and the parametrized values \( \tilde{y}_i \), namely
-$$
-Q(\hat{\beta})=\sum_{i=0}^{n-1}\left(y_i-\tilde{y}_i\right)^2=\left(\hat{y}-\hat{\tilde{y}}\right)^T\left(\hat{y}-\hat{\tilde{y}}\right),
-$$
-
-or using the matrix \( \hat{X} \) as
-$$
-Q(\hat{\beta})=\left(\hat{y}-\hat{X}\hat{\beta}\right)^T\left(\hat{y}-\hat{X}\hat{\beta}\right).
-$$
Generalizing the fitting procedure as a linear algebra problem
-The function
+We redefine in turn the matrix \( \hat{X} \) as
$$
-Q(\hat{\beta})=\left(\hat{y}-\hat{X}\hat{\beta}\right)^T\left(\hat{y}-\hat{X}\hat{\beta}\right),
+\hat{X}=
+\begin{bmatrix}
+x_{00}& x_{01} &x_{02}& \dots & \dots &x_{0,n-1}\\
+x_{10}& x_{11} &x_{12}& \dots & \dots &x_{1,n-1}\\
+x_{20}& x_{21}^1 &x_{22}2& \dots & \dots &x_{2,n-1}\\
+\dots& \dots &\dots& \dots & \dots &\dots\\
+x_{n-1,00}& x_{n-1,1} &x_{n-1,2}& \dots & \dots &x_{n-1,n-1}\\
+\end{bmatrix}
$$
-can be linked to the variance of the quantity \( y_i \) if we interpret the latter as the mean value of for example a numerical experiment. When linking below with the maximum likelihood approach below, we will indeed interpret \( y_i \) as a mean value
+and without loss of generality we rewrite again our equations as
$$
-y_{i}=\langle y_i \rangle = \beta_0x_{i,0}+\beta_1x_{i,1}+\beta_2x_{i,2}+\dots+\beta_{n-1}x_{i,n-1}+\epsilon_i,
+\hat{y} = \hat{X}\hat{\beta}+\hat{\epsilon}.
$$
-where \( \langle y_i \rangle \) is the mean value. Keep in mind also that till now we have treated \( y_i \) as the exact value. Normally, the response (dependent or outcome) variable \( y_i \) the outcome of a numerical experiment or another type of experiment and is thus only an approximation to the true value. It is then always accompanied by an error estimate, often limited to a statistical error estimate given by the standard deviation discussed earlier. In the discussion here we will treat \( y_i \) as our exact value for the response variable.
-
-
-In order to find the parameters \( \beta_i \) we will then minimize the spread of \( Q(\hat{\beta}) \) by requiring
-$$
-\frac{\partial Q(\hat{\beta})}{\partial \beta_j} = \frac{\partial }{\partial \beta_j}\left[ \sum_{i=0}^{n-1}\left(y_i-\beta_0x_{i,0}+\beta_1x_{i,1}+\beta_2x_{i,2}+\dots+\beta_{n-1}x_{i,n-1}\right)^2\right]=0,
-$$
-
-which results in
-$$
-\frac{\partial Q(\hat{\beta})}{\partial \beta_j} = -2\left[ \sum_{i=0}^{n-1}x_{ij}\left(y_i-\beta_0x_{i,0}+\beta_1x_{i,1}+\beta_2x_{i,2}+\dots+\beta_{n-1}x_{i,n-1}\right)\right]=0,
-$$
-
-or in a matrix-vector form as
-$$
-\frac{\partial Q(\hat{\beta})}{\partial \hat{\beta}} = 0 = \hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right).
-$$
-
-
+The left-hand side of this equation forms know. Our error vector \( \hat{\epsilon} \) and the parameter vector \( \hat{\beta} \) are our unknow quantities. How can we obtain the optimal set of \( \beta_i \) values?
-We can rewrite
+We have defined the matrix \( \hat{X} \)
$$
-\frac{\partial Q(\hat{\beta})}{\partial \hat{\beta}} = 0 = \hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right),
+\begin{align*}
+y_0&=\beta_0x_{00}+\beta_1x_{01}+\beta_2x_{02}+\dots+\beta_{n-1}x_{0n-1}+\epsilon_0\\
+y_1&=\beta_0x_{10}+\beta_1x_{11}+\beta_2x_{12}+\dots+\beta_{n-1}x_{1n-1}+\epsilon_1\\
+y_2&=\beta_0x_{20}+\beta_1x_{21}+\beta_2x_{22}+\dots+\beta_{n-1}x_{2n-1}+\epsilon_1\\
+\dots & \dots \\
+y_{i}&=\beta_0x_{i0}+\beta_1x_{i1}+\beta_2x_{i2}+\dots+\beta_{n-1}x_{in-1}+\epsilon_1\\
+\dots & \dots \\
+y_{n-1}&=\beta_0x_{n-1,0}+\beta_1x_{n-1,2}+\beta_2x_{n-1,2}+\dots+\beta_1x_{n-1,n-1}+\epsilon_{n-1}.\\
+\end{align*}
$$
-
-as
-$$
-\hat{X}^T\hat{y} = \hat{X}^T\hat{X}\hat{\beta},
-$$
-
-and if the matrix \( \hat{X}^T\hat{X} \) is invertible we have the solution
-$$
-\hat{\beta} =\left(\hat{X}^T\hat{X}\right)^{-1}\hat{X}^T\hat{y}.
-$$
-
-The residuals \( \hat{\epsilon} \) are in turn given by
-$$
-\hat{\epsilon} = \hat{y}-\hat{\tilde{y}} = \hat{y}-\hat{X}\hat{\beta},
-$$
-
-and with
-$$
-\hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right)= 0,
-$$
-
-we have
-$$
-\hat{X}^T\hat{\epsilon}=\hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right)= 0,
-$$
-
-meaning that the solution for \( \hat{\beta} \) is the one which minimizes the residuals. Later we will link this with the maximum likelihood approach.
-
-
@@ -175,6 +171,10 @@ meaning that the solution for \( \hat{\beta} \) is the one which minimizes the r
-Here we derive the equations for the SVD.
+We well use this matrix to define the approximation \( \hat{\tilde{y}} \) via the unknown quantity \( \hat{\beta} \) as
+$$
+\hat{\tilde{y}}= \hat{X}\hat{\beta},
+$$
+
+and in order to find the optimal parameters \( \beta_i \) instead of solving the above linear algebra problem, we define a function which gives a measure of the spread between the values \( y_i \) (which represent hopefully the exact values) and the parametrized values \( \tilde{y}_i \), namely
+$$
+Q(\hat{\beta})=\sum_{i=0}^{n-1}\left(y_i-\tilde{y}_i\right)^2=\left(\hat{y}-\hat{\tilde{y}}\right)^T\left(\hat{y}-\hat{\tilde{y}}\right),
+$$
+
+or using the matrix \( \hat{X} \) as
+$$
+Q(\hat{\beta})=\left(\hat{y}-\hat{X}\hat{\beta}\right)^T\left(\hat{y}-\hat{X}\hat{\beta}\right).
+$$
-
@@ -144,6 +173,11 @@ Here we derive the equations for the SVD.
+The function
+$$
+Q(\hat{\beta})=\left(\hat{y}-\hat{X}\hat{\beta}\right)^T\left(\hat{y}-\hat{X}\hat{\beta}\right),
+$$
+
+can be linked to the variance of the quantity \( y_i \) if we interpret the latter as the mean value of for example a numerical experiment. When linking below with the maximum likelihood approach below, we will indeed interpret \( y_i \) as a mean value
+$$
+y_{i}=\langle y_i \rangle = \beta_0x_{i,0}+\beta_1x_{i,1}+\beta_2x_{i,2}+\dots+\beta_{n-1}x_{i,n-1}+\epsilon_i,
+$$
+
+where \( \langle y_i \rangle \) is the mean value. Keep in mind also that till now we have treated \( y_i \) as the exact value. Normally, the response (dependent or outcome) variable \( y_i \) the outcome of a numerical experiment or another type of experiment and is thus only an approximation to the true value. It is then always accompanied by an error estimate, often limited to a statistical error estimate given by the standard deviation discussed earlier. In the discussion here we will treat \( y_i \) as our exact value for the response variable.
+
+
+In order to find the parameters \( \beta_i \) we will then minimize the spread of \( Q(\hat{\beta}) \) by requiring
+$$
+\frac{\partial Q(\hat{\beta})}{\partial \beta_j} = \frac{\partial }{\partial \beta_j}\left[ \sum_{i=0}^{n-1}\left(y_i-\beta_0x_{i,0}+\beta_1x_{i,1}+\beta_2x_{i,2}+\dots+\beta_{n-1}x_{i,n-1}\right)^2\right]=0,
+$$
+
+which results in
+$$
+\frac{\partial Q(\hat{\beta})}{\partial \beta_j} = -2\left[ \sum_{i=0}^{n-1}x_{ij}\left(y_i-\beta_0x_{i,0}+\beta_1x_{i,1}+\beta_2x_{i,2}+\dots+\beta_{n-1}x_{i,n-1}\right)\right]=0,
+$$
+
+or in a matrix-vector form as
+$$
+\frac{\partial Q(\hat{\beta})}{\partial \hat{\beta}} = 0 = \hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right).
+$$
+
+
+The residuals \( \hat{\epsilon} \) are in turn given by
+$$
+\hat{\epsilon} = \hat{y}-\hat{\tilde{y}} = \hat{y}-\hat{X}\hat{\beta},
+$$
+
+and with
+$$
+\hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right)= 0,
+$$
+
+we have
+$$
+\hat{X}^T\hat{\epsilon}=\hat{X}^T\left( \hat{y}-\hat{X}\hat{\beta}\right)= 0,
+$$
+
+meaning that the solution for \( \hat{\beta} \) is the one which minimizes the residuals. Later we will link this with the maximum likelihood approach.
+
+
+How can we use the singular value decomposition to find the parameters \( \beta_j \)? More details will come. We first note that a general \( m\times n \) matrix \( \hat{A} \) can be written in terms of a diagonal matrix \( \hat{\Sigma} \) of dimensionality \( n\times n \) and two orthognal matrices \( \hat{U} \) and \( \hat{V} \), where the first has dimensionality \( m \times n \) and the last dimensionality \( n\times n \). We have then
+$$
+\hat{A} = \hat{U}\hat{\Sigma}\hat{V}
+$$
+
We well use this matrix to define the approximation \( \hat{\tilde{y}} \) via the unknown quantity \( \hat{\beta} \) as
$$
@@ -355,7 +380,7 @@ $$
-
Interpretations and optimizing our parameters
+
Interpretations and optimizing our parameters
@@ -403,7 +428,7 @@ $$
-
Interpretations and optimizing our parameters
+
Interpretations and optimizing our parameters
@@ -428,6 +453,16 @@ $$
$$
+
+
+
+
+
+
+
Interpretations and optimizing our parameters
+
+
+
The residuals \( \hat{\epsilon} \) are in turn given by
$$
@@ -457,11 +492,16 @@ meaning that the solution for \( \hat{\beta} \) is the one which minimizes the r
-
The singular value decompostion
+
The singular value decompostion
-Here we derive the equations for the SVD.
+How can we use the singular value decomposition to find the parameters \( \beta_j \)? More details will come. We first note that a general \( m\times n \) matrix \( \hat{A} \) can be written in terms of a diagonal matrix \( \hat{\Sigma} \) of dimensionality \( n\times n \) and two orthognal matrices \( \hat{U} \) and \( \hat{V} \), where the first has dimensionality \( m \times n \) and the last dimensionality \( n\times n \). We have then
+
+$$
+\hat{A} = \hat{U}\hat{\Sigma}\hat{V}
+$$
+
diff --git a/doc/pub/Regression/html/Regression-solarized.html b/doc/pub/Regression/html/Regression-solarized.html
index 1bf399f0a..65fb3c572 100644
--- a/doc/pub/Regression/html/Regression-solarized.html
+++ b/doc/pub/Regression/html/Regression-solarized.html
@@ -66,20 +66,33 @@ div { text-align: justify; text-justify: inter-word; }
2,
None,
'___sec2'),
- ('Generalizing the fitting procedure as a linear algebra problem',
+ ('Rewriting the fitting procedure as a linear algebra problem, follows',
2,
None,
'___sec3'),
- ('Optimizing our parameters', 2, None, '___sec4'),
- ('Interpretations and optimizing our parameters',
+ ('Generalizing the fitting procedure as a linear algebra problem',
+ 2,
+ None,
+ '___sec4'),
+ ('Generalizing the fitting procedure as a linear algebra problem',
2,
None,
'___sec5'),
+ ('Optimizing our parameters', 2, None, '___sec6'),
+ ('Optimizing our parameters, more details', 2, None, '___sec7'),
('Interpretations and optimizing our parameters',
2,
None,
- '___sec6'),
- ('The singular value decompostion', 2, None, '___sec7')]}
+ '___sec8'),
+ ('Interpretations and optimizing our parameters',
+ 2,
+ None,
+ '___sec9'),
+ ('Interpretations and optimizing our parameters',
+ 2,
+ None,
+ '___sec10'),
+ ('The singular value decompostion', 2, None, '___sec11')]}
end of tocinfo -->
Generalizing the fitting procedure as a linear algebra problem
+
+
+
We redefine in turn the matrix \( \hat{X} \) as
$$
\hat{X}=
@@ -262,7 +295,7 @@ The left-hand side of this equation forms know. Our error vector \( \hat{\epsilo
We well use this matrix to define the approximation \( \hat{\tilde{y}} \) via the unknown quantity \( \hat{\beta} \) as
$$
\hat{\tilde{y}}= \hat{X}\hat{\beta},
@@ -299,7 +341,7 @@ $$
The residuals \( \hat{\epsilon} \) are in turn given by
$$
\hat{\epsilon} = \hat{y}-\hat{\tilde{y}} = \hat{y}-\hat{X}\hat{\beta},
@@ -381,11 +434,14 @@ meaning that the solution for \( \hat{\beta} \) is the one which minimizes the r
-
The singular value decompostion
+
The singular value decompostion
-Here we derive the equations for the SVD.
+How can we use the singular value decomposition to find the parameters \( \beta_j \)? More details will come. We first note that a general \( m\times n \) matrix \( \hat{A} \) can be written in terms of a diagonal matrix \( \hat{\Sigma} \) of dimensionality \( n\times n \) and two orthognal matrices \( \hat{U} \) and \( \hat{V} \), where the first has dimensionality \( m \times n \) and the last dimensionality \( n\times n \). We have then
+$$
+\hat{A} = \hat{U}\hat{\Sigma}\hat{V}
+$$
diff --git a/doc/pub/Regression/html/Regression.html b/doc/pub/Regression/html/Regression.html
index 8c775ba7f..d961dadb4 100644
--- a/doc/pub/Regression/html/Regression.html
+++ b/doc/pub/Regression/html/Regression.html
@@ -71,20 +71,33 @@ div { text-align: justify; text-justify: inter-word; }
2,
None,
'___sec2'),
- ('Generalizing the fitting procedure as a linear algebra problem',
+ ('Rewriting the fitting procedure as a linear algebra problem, follows',
2,
None,
'___sec3'),
- ('Optimizing our parameters', 2, None, '___sec4'),
- ('Interpretations and optimizing our parameters',
+ ('Generalizing the fitting procedure as a linear algebra problem',
+ 2,
+ None,
+ '___sec4'),
+ ('Generalizing the fitting procedure as a linear algebra problem',
2,
None,
'___sec5'),
+ ('Optimizing our parameters', 2, None, '___sec6'),
+ ('Optimizing our parameters, more details', 2, None, '___sec7'),
('Interpretations and optimizing our parameters',
2,
None,
- '___sec6'),
- ('The singular value decompostion', 2, None, '___sec7')]}
+ '___sec8'),
+ ('Interpretations and optimizing our parameters',
+ 2,
+ None,
+ '___sec9'),
+ ('Interpretations and optimizing our parameters',
+ 2,
+ None,
+ '___sec10'),
+ ('The singular value decompostion', 2, None, '___sec11')]}
end of tocinfo -->
@@ -99,8 +112,8 @@ MathJax.Hub.Config({
}
});
-
@@ -126,7 +139,7 @@ MathJax.Hub.Config({
[2] Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University
-
Oct 17, 2017
+
Oct 18, 2017
@@ -173,6 +186,8 @@ where \( \epsilon_i \) is the error in our approximation.
+
+
Rewriting the fitting procedure as a linear algebra problem
Generalizing the fitting procedure as a linear algebra problem
+
+
+
We redefine in turn the matrix \( \hat{X} \) as
$$
\hat{X}=
@@ -267,7 +300,7 @@ The left-hand side of this equation forms know. Our error vector \( \hat{\epsilo
We well use this matrix to define the approximation \( \hat{\tilde{y}} \) via the unknown quantity \( \hat{\beta} \) as
$$
\hat{\tilde{y}}= \hat{X}\hat{\beta},
@@ -304,7 +346,7 @@ $$
The residuals \( \hat{\epsilon} \) are in turn given by
$$
\hat{\epsilon} = \hat{y}-\hat{\tilde{y}} = \hat{y}-\hat{X}\hat{\beta},
@@ -386,11 +439,14 @@ meaning that the solution for \( \hat{\beta} \) is the one which minimizes the r
-
The singular value decompostion
+
The singular value decompostion
-Here we derive the equations for the SVD.
+How can we use the singular value decomposition to find the parameters \( \beta_j \)? More details will come. We first note that a general \( m\times n \) matrix \( \hat{A} \) can be written in terms of a diagonal matrix \( \hat{\Sigma} \) of dimensionality \( n\times n \) and two orthognal matrices \( \hat{U} \) and \( \hat{V} \), where the first has dimensionality \( m \times n \) and the last dimensionality \( n\times n \). We have then
+$$
+\hat{A} = \hat{U}\hat{\Sigma}\hat{V}
+$$
diff --git a/doc/pub/Regression/ipynb/ipynb-Regression-src.tar.gz b/doc/pub/Regression/ipynb/ipynb-Regression-src.tar.gz
index ba6a46c27..715a2d7de 100644
Binary files a/doc/pub/Regression/ipynb/ipynb-Regression-src.tar.gz and b/doc/pub/Regression/ipynb/ipynb-Regression-src.tar.gz differ
diff --git a/doc/pub/Regression/pdf/Regression-beamer-handouts2x3.pdf b/doc/pub/Regression/pdf/Regression-beamer-handouts2x3.pdf
index b1b74a4c8..3f38065a4 100644
Binary files a/doc/pub/Regression/pdf/Regression-beamer-handouts2x3.pdf and b/doc/pub/Regression/pdf/Regression-beamer-handouts2x3.pdf differ
diff --git a/doc/pub/Regression/pdf/Regression-beamer.pdf b/doc/pub/Regression/pdf/Regression-beamer.pdf
index 2c1056dcf..39e3cc363 100644
Binary files a/doc/pub/Regression/pdf/Regression-beamer.pdf and b/doc/pub/Regression/pdf/Regression-beamer.pdf differ
diff --git a/doc/pub/Regression/pdf/Regression-minted.pdf b/doc/pub/Regression/pdf/Regression-minted.pdf
index a57fa60e1..1bd7aa950 100644
Binary files a/doc/pub/Regression/pdf/Regression-minted.pdf and b/doc/pub/Regression/pdf/Regression-minted.pdf differ
diff --git a/doc/src/Regression/Regression.do.txt b/doc/src/Regression/Regression.do.txt
index e3b4bf899..5df8e53a8 100644
--- a/doc/src/Regression/Regression.do.txt
+++ b/doc/src/Regression/Regression.do.txt
@@ -32,6 +32,8 @@ y=y(x) \rightarrow y(x_i)=\tilde{y}_i+\epsilon_i=\sum_{j=0}^{n-1} \beta_i x_i^j+
where $\epsilon_i$ is the error in our approximation.
!eblock
+
+
!split
===== Rewriting the fitting procedure as a linear algebra problem =====
!bblock
@@ -45,6 +47,12 @@ y_2&=\beta_0+\beta_1x_2^1+\beta_2x_2^2+\dots+\beta_{n-1}x_2^{n-1}+\epsilon_2\\
y_{n-1}&=\beta_0+\beta_1x_{n-1}^1+\beta_2x_{n-1}^2+\dots+\beta_1x_{n-1}^{n-1}+\epsilon_{n-1}.\\
\end{align*}
!et
+!eblock
+
+
+!split
+===== Rewriting the fitting procedure as a linear algebra problem, follows =====
+!bblock
Defining the vectors
!bt
\[
@@ -99,6 +107,12 @@ y_{i}&=\beta_0x_{i0}+\beta_1x_{i1}+\beta_2x_{i2}+\dots+\beta_{n-1}x_{in-1}+\epsi
y_{n-1}&=\beta_0x_{n-1,0}+\beta_1x_{n-1,2}+\beta_2x_{n-1,2}+\dots+\beta_1x_{n-1}^{n-1,n-1}+\epsilon_{n-1}.\\
\end{align*}
!et
+!eblock
+
+
+!split
+===== Generalizing the fitting procedure as a linear algebra problem =====
+!bblock
We redefine in turn the matrix $\hat{X}$ as
!bt
\[
@@ -137,6 +151,12 @@ y_{i}&=\beta_0x_{i0}+\beta_1x_{i1}+\beta_2x_{i2}+\dots+\beta_{n-1}x_{in-1}+\epsi
y_{n-1}&=\beta_0x_{n-1,0}+\beta_1x_{n-1,2}+\beta_2x_{n-1,2}+\dots+\beta_1x_{n-1,n-1}+\epsilon_{n-1}.\\
\end{align*}
!et
+!eblock
+
+
+!split
+===== Optimizing our parameters, more details =====
+!bblock
We well use this matrix to define the approximation $\hat{\tilde{y}}$ via the unknown quantity $\hat{\beta}$ as
!bt
\[
@@ -219,6 +239,12 @@ and if the matrix $\hat{X}^T\hat{X}$ is invertible we have the solution
\hat{\beta} =\left(\hat{X}^T\hat{X}\right)^{-1}\hat{X}^T\hat{y}.
\]
!et
+
+!eblock
+
+!split
+===== Interpretations and optimizing our parameters =====
+!bblock
The residuals $\hat{\epsilon}$ are in turn given by
!bt
\[
@@ -242,10 +268,16 @@ meaning that the solution for $\hat{\beta}$ is the one which minimizes the resid
!eblock
+
!split
===== The singular value decompostion =====
!bblock
-Here we derive the equations for the SVD.
+How can we use the singular value decomposition to find the parameters $\beta_j$? More details will come. We first note that a general $m\times n$ matrix $\hat{A}$ can be written in terms of a diagonal matrix $\hat{\Sigma}$ of dimensionality $n\times n$ and two orthognal matrices $\hat{U}$ and $\hat{V}$, where the first has dimensionality $m \times n$ and the last dimensionality $n\times n$. We have then
+!bt
+\[
+\hat{A} = \hat{U}\hat{\Sigma}\hat{V}
+\]
+!et
!eblock