**IFOS2D** (**I**nversion of **F**ull **O**bserved **S**eismograms) is a 2-D elastic full waveform inversion code.
The inversion problem is solved by a conjugate gradient method and the gradients are computed in the time domain by the adjoint state method.
The forward modeling is done by a time domain Finite-Difference scheme.
The forward modeling is done by a time domain Finite-Difference scheme.
IFOS2D is the reverse (inverse) of our 2-D Finite-Difference forward solver [**SOFI2D**](https://git.scc.kit.edu/GPIAG-Software/SOFI2D).
The [**manual**](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/wikis/home) is included in the download archive or can be downloaded [here](https://git.scc.kit.edu/GPIAG-Software/IFOS2D/wikis/home).
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.
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Please use this list also to ask questions or to report problems or bugs.
@@ -322,7 +322,9 @@ The locations of the receivers may either be specified in a separate file REC\_F
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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.
sectiondata_mult_section+=intseis_sectiondata[i][j]*intseis_section[i][j];/* calculation of dot product for measured (section) and synthetic (sectiondata) data*/