---
title: "Double Precision Version | Technical Reference"
slug: "double-precesion-version"
description: "Learn about the double precision version of the 2D solver executable. "
tags: ["2D modelling"]
updated: 2022-11-01T19:00:54Z
published: 2022-11-01T19:00:54Z
canonical: "help.floodmodeller.com/double-precesion-version"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.floodmodeller.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Double Precision Version

There is also a double precision version of the 2D Solver executable.

Users may find that the double precision version reduces mass error often associated with models simulating very small depths of water, such as direct rainfall models.

NoteWe always recommend the use of double precision when using rainfall boundary inputs. Often rainfall flood depths are small and without double precision, "small" cell volumes can be lost (rounded to zero). This can lead to significant overall losses and larger mass balance errors.

Double precision simulations are performed by ISIS2D_dp.exe

If the modeller feels that his/her model should be run in double precision, he/she may insert a <double_precision> element into the <run_data> element of the .XML file which either warns that the model should be run in double precision, or forces the model to be run in double precision.

The following example code snippet warns the user that the model should ideally be run in double precision mode:

<run_data>

<time_step> 2 </time_step>

< scheme > ADI < /scheme >

<double_precision>advised</double_precision>

</run_data>

The following example code snippet forces the model to be run in double precision by causing a single precision simulation to fail with an error message:

<run_data>

<time_step> 2 </time_step>

< scheme > ADI < /scheme >

<double_precision>required</double_precision>

</run_data>