@@ -10,7 +10,7 @@ The [**manual**](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/wikis/home) is in
# Download and Newsletter
You can download the [**latest Release**](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/tags/Release_2.0.1) or the current [**Beta-Version**](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/tree/develop).
You can download the [**latest Release 2.0.2**](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/tags/Release_2.0.2) or the current [**Beta-Version**](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/tree/develop).
To receive news and updates please [register](http://www.gpi.kit.edu/Software-FWI.php) on the email list [IFOS@lists.kit.edu](http://www.gpi.kit.edu/Software-FWI.php).
Please use this list also to ask questions or to report problems or bugs.
With this option pure acoustic modelling and/or inversion can be performed (ACOUSTIC = 1). Only a P-wave and a density model need to be provided. Acoustic modelling and inversion can be a quick estimate, especially for marine environments.
For acoustic modelling the option VELOCITY is not available and only PARAMETERIZATION = 1 is possible.
For acoustic modelling only PARAMETERIZATION = 1 is possible.
\section{PSV and SH modelling}
{\color{blue}{\begin{verbatim}
...
...
@@ -322,7 +322,9 @@ The locations of the receivers may either be specified in a separate file REC\_F
\end{verbatim}}}
These receiver coordinates in REC\_FILE are shifted by REFREC[1], REFREC[2] into the x- and y-direction, respectively. This allows for completely moving the receiver spread without modifying REC\_FILE. This may be useful for the simulation of moving profiles in reflection seismics.
If READREC=0 the receiver locations must be specified in the parameter file. In this case, it is assumed that the receivers are located along a straight line. The first receiver position is defined by (XREC1, YREC1), and the last receiver position by (XREC1, YREC1). The spacing between receivers is NGEOPH grid points.
If READREC=0 the receiver locations must be specified in the parameter file. In this case, it is assumed that the receivers are located along a straight line. The first receiver position is defined by (XREC1, YREC1), and the last receiver position by (XREC1, YREC1). The spacing between receivers is NGEOPH grid points.
READREC=2 is made for a moving streamer aquisition geometry. The receiver positions for shot 1 must be specified in the parameter file (as described for READREC=0). For all other shots the receiver positions are moved according to the movement of the following source. This implementation allows a memory saving usage of moving geometries. The receivers must be in the same depth and all receivers must be located in the model for all shots.
Receivers are always located on full grid indices, i.e. a receiver that is located between two grid points will be shifted by the FD program to the closest next grid point. It is not yet possible
to output seismograms for arbitrary receiver locations since this would require a certain wavefield interpolation.
...
...
@@ -504,12 +506,12 @@ Default values are:
With the use of a workflow file, you can define different FWI stages. For instance, one FWI stage could refer to one corner frequency of a low-pass filter or to a specific time window. Every line in the workflow file corresponds to one FWI stage. To use a workflow file the switch USE\_WORKFLOW have to be set to 1. The algorithm will automatically change to the next line of the workflow file if the abort criterium of the current line is reached or if no step length could be found which reduces the misfit. The structure of the variables inside the workflow file is as follow: \\
The first column is the number of the line. With INV\_* etc. you can activate the inversion for VS, VP or RHO, respectively. The abort criterium in percent for this FWI stage will be the declared in the variable PRO. With TIME\_FILT you can activate the frequency filtering with the corner frequency FC. WAVETYPE can be used to switch between PSV and SH modeling, however it is recommended to use PSV modeling (WAVETYPE==1) due to the current development on SH modeling. The following to zeros are placeholders for an upcoming update. With EPRECOND and EPSILON\_WE you can control the approx. Hessian. Please note, that all features which are used eg. TIME\_FILT (see section \ref{sec:filtering}) within the workflow have to be activated in the .JSON file.
The first column is the number of the line. With INV\_* etc. you can activate the inversion for VS, VP or RHO, respectively. The abort criterium in percent for this FWI stage will be the declared in the variable PRO. With TIME\_FILT you can activate the frequency filtering with the corner frequency F\_HIGH\_PASS of the high-pass and F\_LOW\_PASS of the low-pass filter. WAVETYPE can be used to switch between PSV and SH modeling, however it is recommended to use PSV modeling (WAVETYPE==1) due to the current development on SH modeling. The following to zeros are placeholders for an upcoming update. With EPRECOND and EPSILON\_WE you can control the approx. Hessian. Please note, that all features which are used eg. TIME\_FILT (see section \ref{sec:filtering}) within the workflow have to be activated in the .JSON file.
For an example of a workflow file, have a look in the par/ folder.
...
...
@@ -857,7 +859,7 @@ For GRAD\_FILT\_WAVELENGTH = 1 (and TIME\_FILT=1) a new wavelength dependent fil