From 9997f39a82c9ac7178575f37c0dc12d7f79c3d97 Mon Sep 17 00:00:00 2001
From: Thomas Forbriger <Thomas.Forbriger@kit.edu>
Date: Fri, 22 Jul 2016 10:49:05 +0200
Subject: [PATCH] libstfinv [WP][DOC]: locate appropriate location for
 application of taper

---
 src/libs/libstfinv/stfinvfourier.cc |  1 +
 src/libs/libstfinv/stfinvfourier.h  | 25 ++++++++++++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/libs/libstfinv/stfinvfourier.cc b/src/libs/libstfinv/stfinvfourier.cc
index ca261d22..f0390b65 100644
--- a/src/libs/libstfinv/stfinvfourier.cc
+++ b/src/libs/libstfinv/stfinvfourier.cc
@@ -271,6 +271,7 @@ namespace stfinv {
 
   void STFFourierDomainEngine::fftoutput()
   {
+    // NOTE: apply taper here
     this->convolve();
     if (Mapplyshift) { this->stfshift(); }
     Mfftengineoutput.c2r();
diff --git a/src/libs/libstfinv/stfinvfourier.h b/src/libs/libstfinv/stfinvfourier.h
index ccef14fe..b3327c76 100644
--- a/src/libs/libstfinv/stfinvfourier.h
+++ b/src/libs/libstfinv/stfinvfourier.h
@@ -57,7 +57,8 @@ namespace stfinv {
    * It provides the FFT from input signals to the workspace through a member
    * functions as well as the convolution of the synthetic data with a given
    * source wavelet Fourier transform and a subsequent FFT to time domain for
-   * the convolved synthetics as well as the source correction filter separately.
+   * the convolved synthetics as well as the source correction filter
+   * separately.
    *
    * \par What STFFourierDomainEngine does for you
    * All derived classes call STFFourierDomainEngine::fftinput prior to
@@ -70,13 +71,27 @@ namespace stfinv {
    * \par
    * When processing has finished, the derived classes should call
    * STFFourierDomainEngine::fftoutput.
-   * This function convolves the synthetic data with the source correction
+   * This function first applies a time domain taper to the correction filter
+   * impulse response if requested (STFFourierDomainEngine::taperstf).
+   * Then it convolves the synthetic data with the source correction
    * filter (STFFourierDomainEngine::convolve).
-   * Then it applies a time shift to the source correction filter if requested
-   * (STFFourierDomainEngine::stfshift).
+   * If requested it applies a time shift to the source correction filter 
+   * as a next step (STFFourierDomainEngine::stfshift).
    * The convolved synthetics as well as the source correction filter then are
    * transformed to time domain and written to the users workspace
-   * ((STFFourierDomainEngine::putoutput).
+   * (STFFourierDomainEngine::putoutput).
+   *
+   * \par 
+   * This should take place in the exec-function (e.g.
+   * STFEngineFDLeastSquares::exec) of the derived class.
+   * I.e. the first statement in the exec function is a call to function
+   * STFFourierDomainEngine::fftinput of the base class and the very last
+   * statement is a call to function STFFourierDomainEngine::fftoutput of the
+   * base class.
+   * This also guarantees that STFFourierDomainEngine::fftoutput is only
+   * called once per derived correction filter response.
+   * This is necessary, since otherwise the taper function and the time shift
+   * would be applied twice to the impulse response.
    *
    * \par Layout of Fourier transform arrays
    * The workspace for the Fourier transform engine is initialized by
-- 
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