The Lazy Economist https://blog.modelworks.ch Thoughts on Modelling, Statistics, and Efficient Working Habits Mon, 04 Jan 2021 16:27:52 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.5 https://blog.modelworks.ch/wp-content/uploads/2019/07/cropped-2019-07-31-13_00_31-D__Modelworks_Administration_Buro_Logo-large-small.bmp-32x32.png The Lazy Economist https://blog.modelworks.ch 32 32 Frustrating Start with Oracle https://blog.modelworks.ch/frustrating-start-with-oracle/ Mon, 04 Jan 2021 16:25:40 +0000 http://blog.modelworks.ch/?p=796 Today, as a New Year’s resolution (and for my work), I started learning how to work with Oracle. I know MySQL and MS SQL quite well, so I thought that this would be a piece of cake. How wrong I was!

Oracle Database - Fujitsu Schweiz

Before starting, I had to download Oracle. There is a msi-file for Windows, but when you click it, it can’t finish the installation process and hangs. Well, so I thought, this might be a problem with the rights, so I started it as the administrator: same problem. After searching the internet for 15 minutes, I discovered that many had … Read the rest “Frustrating Start with Oracle”

]]> Today, as a New Year’s resolution (and for my work), I started learning how to work with Oracle. I know MySQL and MS SQL quite well, so I thought that this would be a piece of cake. How wrong I was!

Oracle Database - Fujitsu Schweiz

Before starting, I had to download Oracle. There is a msi-file for Windows, but when you click it, it can’t finish the installation process and hangs. Well, so I thought, this might be a problem with the rights, so I started it as the administrator: same problem. After searching the internet for 15 minutes, I discovered that many had … Read the rest “Frustrating Start with Oracle”

]]> Adding a new environment for code listings in LaTeX https://blog.modelworks.ch/adding-a-new-environment-for-code-listings-in-latex/ Fri, 27 Sep 2019 12:04:22 +0000 http://blog.modelworks.ch/?p=787 Documentation of code in LaTeX is easy: Just use the package listings. To be able to refer to those code snippets, you can define a new environment as follows:

\usepackage{caption}
\DeclareCaptionType[placement={!ht}]{listing}[Listing][Code Listings]

The name of the environment is {listing} and the name used for the caption is [Listing]. It was not necessary to add the name as the default is to take the name of the environment with the first character capitalized. However, I need the last setting to define the title of the list of listings (the default value here is “List of listings”).

This results, with some … Read the rest “Adding a new environment for code listings in LaTeX”

]]> Documentation of code in LaTeX is easy: Just use the package listings. To be able to refer to those code snippets, you can define a new environment as follows:

\usepackage{caption}
\DeclareCaptionType[placement={!ht}]{listing}[Listing][Code Listings]

The name of the environment is {listing} and the name used for the caption is [Listing]. It was not necessary to add the name as the default is to take the name of the environment with the first character capitalized. However, I need the last setting to define the title of the list of listings (the default value here is “List of listings”).

This results, with some … Read the rest “Adding a new environment for code listings in LaTeX”

]]> LaTeX equations in sans-serif font https://blog.modelworks.ch/latex-equations-in-sans-serif-font/ Thu, 26 Sep 2019 12:51:29 +0000 http://blog.modelworks.ch/?p=779 I write most of my text using a sans-serif font using the following code in my preamble:

\renewcommand{\familydefault}{\sfdefault}

Text looks than like this:

However, the equations are shown in a serif-font:

Although no big issue for me, I looked for a solution that produces my equations also in sans-serif format. There is a package for this called newtxsf that does exactly that:

Just add the package in your preamble:

\usepackage{newtxsf}
]]> I write most of my text using a sans-serif font using the following code in my preamble:

\renewcommand{\familydefault}{\sfdefault}

Text looks than like this:

However, the equations are shown in a serif-font:

Although no big issue for me, I looked for a solution that produces my equations also in sans-serif format. There is a package for this called newtxsf that does exactly that:

Just add the package in your preamble:

\usepackage{newtxsf}

]]> Producing stand-alone figures with TikZ in LaTeX https://blog.modelworks.ch/producing-stand-alone-figures-with-tikz-in-latex/ https://blog.modelworks.ch/producing-stand-alone-figures-with-tikz-in-latex/#comments Wed, 21 Aug 2019 06:46:27 +0000 http://blog.modelworks.ch/?p=772 With TikZ (the abbreviation for This is not a drawing program in German) you can produce beautiful figures for your papers (look here for some examples). One problem that often arises is that having the TikZ-code in your LaTeX file is not very efficient when working on the figure: You don’t want to regenerate your paper every time you change something in your figure. Another problem arises when your TikZ code is very long. LaTeX might complain and will not generate the figure.

The easiest way to circumvent these problems is by using a stand-alone file that generates a pdf-file … Read the rest “Producing stand-alone figures with TikZ in LaTeX”

]]> With TikZ (the abbreviation for This is not a drawing program in German) you can produce beautiful figures for your papers (look here for some examples). One problem that often arises is that having the TikZ-code in your LaTeX file is not very efficient when working on the figure: You don’t want to regenerate your paper every time you change something in your figure. Another problem arises when your TikZ code is very long. LaTeX might complain and will not generate the figure.

The easiest way to circumvent these problems is by using a stand-alone file that generates a pdf-file … Read the rest “Producing stand-alone figures with TikZ in LaTeX”

]]> https://blog.modelworks.ch/producing-stand-alone-figures-with-tikz-in-latex/feed/ 2 Automatic line breaks in LaTeX tables https://blog.modelworks.ch/automatic-line-breaks-in-latex-tables/ Wed, 07 Aug 2019 07:58:49 +0000 http://blog.modelworks.ch/?p=761 Tables with lots of text in LaTeX often lead to tables that do not fit on a page. This post shows how to produce tables with automatic line breaks. Here is a simple example of a badly formatted table:

The tabularx package has the possibility to break lines automatically by using the column specifier X:

\begin{table}[!htbp]
  \centering
    \begin{tabularx}{\textwidth}{lX}
    \toprule
    Number     & Description \\
    \midrule
    1          & This is a mighty long text that could go over multiple lines but in a normal table is shown on one line and therefore the table does not fit on the page \\
    2
… Read the rest “Automatic line breaks in LaTeX tables”]]> Tables with lots of text in LaTeX often lead to tables that do not fit on a page. This post shows how to produce tables with automatic line breaks. Here is a simple example of a badly formatted table:

The tabularx package has the possibility to break lines automatically by using the column specifier X:

\begin{table}[!htbp]
  \centering
    \begin{tabularx}{\textwidth}{lX}
    \toprule
    Number     & Description \\
    \midrule
    1          & This is a mighty long text that could go over multiple lines but in a normal table is shown on one line and therefore the table does not fit on the page \\
    2
… Read the rest “Automatic line breaks in LaTeX tables”

]]> DRY: Some useful macros in Gams https://blog.modelworks.ch/dry-some-useful-macros-in-gams/ Wed, 31 Jul 2019 08:46:29 +0000 http://blog.modelworks.ch/?p=707 DRY stands for “Don’t repeat yourself” and is one of the main principles of efficient programming. In Gams, I use some checks over and over again. Instead of rewriting the code or searching for a file with the existing code and copying it, I use macros in Gams. Macros aren’t difficult to write. You can find more on them here in the documentation.

Here is a simple example from the Gams documentation defining and using a macro that calculates the reciprocal of a number:

$macro reciprocal(y) 1/y
scalar z, x1 /2/, x2 /3/;
z = reciprocal(x1) + reciprocal(x2);

More complex … Read the rest “DRY: Some useful macros in Gams”

]]> DRY stands for “Don’t repeat yourself” and is one of the main principles of efficient programming. In Gams, I use some checks over and over again. Instead of rewriting the code or searching for a file with the existing code and copying it, I use macros in Gams. Macros aren’t difficult to write. You can find more on them here in the documentation.

Here is a simple example from the Gams documentation defining and using a macro that calculates the reciprocal of a number:

$macro reciprocal(y) 1/y
scalar z, x1 /2/, x2 /3/;
z = reciprocal(x1) + reciprocal(x2);

More complex … Read the rest “DRY: Some useful macros in Gams”

]]> Checking Mappings in GAMS https://blog.modelworks.ch/checking-mappings-in-gams/ Sun, 21 Jul 2019 13:13:45 +0000 http://blog.modelworks.ch/?p=694 In my previous post, I showed an easy way to aggregate a matrix using mappings in GAMS. If you use a small mapping, you probably won’t make any errors, but if the sets in the mappings have many elements, the chance of an error rises. For example, you forget to map one of the elements on either side, or you map one element twice.

Tom Rutherford wrote a nice piece of code to check your mappings. This code raises an error as soon as you make one of the mistakes mentioned above.

Let us first set up a simple … Read the rest “Checking Mappings in GAMS”

]]> In my previous post, I showed an easy way to aggregate a matrix using mappings in GAMS. If you use a small mapping, you probably won’t make any errors, but if the sets in the mappings have many elements, the chance of an error rises. For example, you forget to map one of the elements on either side, or you map one element twice.

Tom Rutherford wrote a nice piece of code to check your mappings. This code raises an error as soon as you make one of the mistakes mentioned above.

Let us first set up a simple … Read the rest “Checking Mappings in GAMS”

]]> New: Possibility to subscribe to this blog https://blog.modelworks.ch/new-possibility-to-subscribe-to-this-blog/ Sat, 13 Jul 2019 08:08:54 +0000 http://blog.modelworks.ch/?p=690 If you can’t do without my blog posts and don’t want to check if there are any new posts, you can subscribe to this blog. Just scroll down in the widget bar on the right side until you find the following:

Add your email address and wait for the confirmation email.

]]> If you can’t do without my blog posts and don’t want to check if there are any new posts, you can subscribe to this blog. Just scroll down in the widget bar on the right side until you find the following:

Add your email address and wait for the confirmation email.

]]> Aggregating tables in Gams in a flexible way using mappings and compile-time variables https://blog.modelworks.ch/aggregating-tables-in-gams-in-a-flexible-way-using-mappings-and-compile-time-variables/ Thu, 04 Jul 2019 12:42:41 +0000 http://blog.modelworks.ch/?p=680 Gams makes aggregating tables quite easy. Imagine you a table with data for 100 sectors but you want to run your model in the testing phase for an aggregation of these sectors (e.g. an aggregate the 100 sectors to the three sector groups “agriculture”, “industry”, and “services”). This is a typical situation in CGE (computable general equilibrium modeling): you have a social accounting matrix for your country and you want to start with a simple model having only a few sectors, one household, no taxes, and no government).
In Gams you simply introduce a mapping that maps the 100 sectors … Read the rest “Aggregating tables in Gams in a flexible way using mappings and compile-time variables”

]]> Gams makes aggregating tables quite easy. Imagine you a table with data for 100 sectors but you want to run your model in the testing phase for an aggregation of these sectors (e.g. an aggregate the 100 sectors to the three sector groups “agriculture”, “industry”, and “services”). This is a typical situation in CGE (computable general equilibrium modeling): you have a social accounting matrix for your country and you want to start with a simple model having only a few sectors, one household, no taxes, and no government).
In Gams you simply introduce a mapping that maps the 100 sectors … Read the rest “Aggregating tables in Gams in a flexible way using mappings and compile-time variables”

]]> Good Books for Learning Python https://blog.modelworks.ch/good-books-for-learning-python/ Fri, 28 Jun 2019 12:07:34 +0000 http://blog.modelworks.ch/?p=628 After some hesitation, I finally decided to start with learning Python. I had some hesitations because I am used to R and that is a different kind of cookie. The decision was made easier because I am working on a project with models developed by other colleagues in Python (and Matlab). Furthermore, although Shiny in R is a great way for visualization of results, I got stuck building a combination of results and information. Python offers Dash (some nice examples can be found in the Dash Galley). Another reason is that nowadays you can use Python in your Gams … Read the rest “Good Books for Learning Python”

]]> After some hesitation, I finally decided to start with learning Python. I had some hesitations because I am used to R and that is a different kind of cookie. The decision was made easier because I am working on a project with models developed by other colleagues in Python (and Matlab). Furthermore, although Shiny in R is a great way for visualization of results, I got stuck building a combination of results and information. Python offers Dash (some nice examples can be found in the Dash Galley). Another reason is that nowadays you can use Python in your Gams … Read the rest “Good Books for Learning Python”

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