**Welcome to THETAWIKI**. If you like to create or edit a page please make sure to login or register an account. All registered users please make sure to provide a valid email address.

# Excel Bridge

## Contents

## What is the Excel Bridge?

The Excel Bridge is the esiest way to run a model at home. Any model marked with the "Run This At Home" icon can be run directly from within your Excel. You only need to install the Excel Bridge add-in into Excel.

There are two ways to start your simulations. You can run the prepared models from our wiki. All the simulations are performed in our Thetaris cloud. Alternatively, you can download and install the Theta Suite XL and create your own simulation models. In that case, your models are calculated locally, completely independent of the Thetaris cloud.

## Installation

- Excel Bridge: If you only install the Excel Bridge you may run all of our predefined models in the cloud.
- Theta Suite: If you also install Theta Suite you may define your own models in our model definition language ThetaML and run them locally.

## Ready to use models

There is a list of ready to use models. Each model is extensively documented in this wiki. You can run them after installing the Excel Bridge. If you want to modify these models you can install the Theta Suite to do so.

## How to use the Excel Bridge

You can either create your own Excel sheet or use one of the Excel sheet templates we already prepared for you as part of the Excel Bridge package. For example, you can open an empty Excel workbook and follow the steps below:

### The Excel Bridge Toolbar

After installation a new entry is shown in your Excel ribbon: **Thetaris**. From there you can connect to a running Theta Suite installation. By default you are direcly connected to our Theta Suite cloud service.

To trigger your own simulation you can start and select an empty cell in your Excel work sheet. Then press the "Run ThetaSuite" button in the "Thetaris" tab of the ribbon.

### The Excel Bridge Configurator Window

With a click on the "Run ThetaSuite" button, the Theta Configurator window appears. If you have not yet done so, we must first configure the ThetaML script containing your model. Simply type the web address of the online model, then press the "OK" button. Using a locally installed Theta Suite, you could also simply open a file from your hard disk.

In this example, the model we use is to calculate the sum of two input parameters.

This example assumes that the referenced file is a simple ThetaML model with the following content:

model SumOf2 import a "the first parameter" import b "the second parameter" export x "the sum of a and b" x = a + b end

#### Select Your Model

Because ThetaML files may contain multiple models, we must click the combo box and select the model we want to run. In our example this is the model "SumOf2". Again, the model can export multiple variables. We choose the output as "x". The other combo box offering "scenario" or "mean" refers to the choice between output types that is relevant for Monte Carlo simulations.

#### Set Your Parameters

In order to set all the parameters, we can either simply type the proper value in the text box or select a value from Excel by pressing the button right of the text box and selecting the cell to reference.

### See Your Simulation Result

After all the parameters are set up, press the "OK" button. This action closes the configurator window and sets a new formula in the Excel cell, something like "=ThetaCall(…)". As a matter of fact, you could have directly typed that formula into the cell, but that would have been more complicated. Anyway, the formula is in the cell now and Excel triggers its execution. Depending on the complexity of your model and our cloud speed we wait a certain time for the calculation to complete. As expected the value 5 appears in the cell.