The first Madagascar school for advanced users took place in Qingdao, China, on August  8-9, 2015, and was hosted by the China University of Petroleum (East China).

The local organizers were Professor Qizhen Du (China University of Petroleum) and Dr. Gang Fang (Qingdao Institute of Marine Geology).

The school attracted more than 100 participants from 15 different organizations, including 10 Chinese universities. The program included not only lectures on different advanced topics in the use of Madagascar but also presentations from different users about their personal experiences with using Madagascar for geophysical research. The school materials are available on the website.

The school timing and location cleverly coincided with the famous Qingdao International Beer Festival, the biggest one of its kind in Asia.

sfmutter performs a mute operation, common in prestack seismic data processing.

The following example from bei/wvs/vscan shows a seismic CMP gather before and after a mute.

sfmutter multiples the input by a weight, which follows the equation

$$W(t,x) = \left\{\begin{array}{rl} 0 & \quad \mbox{for} \quad t – t_0 < p_0\,(x-x_0) \\ 1 & \quad \mbox{for} \quad t – t_0 > \Delta t + p_1\,(x-x_0) \end{array}\right.$$

The weight is smoothly interpolated in between the two regions. Different parameters appearing in this equation can be specified as inputs for sfmutter: t0= and x0= correspond to $t_0$ and $x_0$; tp= corresponds to $\Delta t$; slope0= and slopep= correspond to $p_0$ and $p_1$, respectively. The slope can be specified by velocity v0= such that $p_0=1/v_0$. By default, $p_1=p_0$.

The parameter half= indicates whether the horizontal axis corresponds to half-offset instead of the full offset (true by default). In case of irregular offsets, they can be provides in a file specified by offset=. The parameter abs= controls whether to use the absolute value of the offset in the calculation of the mute (true by default).

To make a hyperbolic mute, instead of the default linear mute, use hyper=y. In this case, the equation changes to

$$W(t,x) = \left\{\begin{array}{rl} 0 & \quad \mbox{for} \quad (t-t_0)^2 < p_0^2\,(x-x_0)^2 \\ 1 & \quad \mbox{for} \quad (t-t_0)^2 > (\Delta t)^2 + p_1^2\,(x-x_0)^2 \end{array}\right.$$

The following example from xjtu/mcaseislet/sep2 applies a hyperbolic mute for an SRME prediction of surface-related multiple reflections:

For inner mute, specified by inner=y, the signs in the equation are reversed. The following example from milano/taupvel/cmp applies an inner mute to a Radon-transformed CMP gather:

10 previous programs of the month:

• sfintbin
• sfbox
• sfslant
• sfgrey
• sfhistogram
• sfmf
• sfbin
• sfthreshold
• sfsigmoid
• sfmax1

sfintbin uses trace headers to arrange input traces in a 3-D cube.

The input to this program typically comes from reading a SEGY file with sfsegyread.

The following example from tccs/phase/boon3 shows a typical output:

sfintbin takes as an input a 2-D trace file and its corresponding trace header file (specified by head=). The header file is assumed to contain integer values. The output 3-D cube is generated according to trace header keys, which can be specified by name (xk=, yk=) or by number (xkey=, ykey=). In the example above, the parameters are xk=cdp and yk=fldr. If you are unsure which keys to use, try sfheaderattr. The range of values can be controlled with xmin=, xmax=, ymin=, ymax=.

sfintbin performs a very simple operation: it goes through the input file and assigns traces to the output according to their header keys. If there are several traces with the same x and y keys, the last one survives. If there are bins in the output with no input, they are filled with zeros. You can output the mask of empty traces using mask=. You can output the mapping of traces using map=. The latter is particularly useful for the inverse operation (mapping from 3-D back to 2-D), which can be performed with inv=y.

For an absent trace header key, which corresponds to a trace number in a gather, you can set xkey= to a negative number. For this to work, the input needs to be sorted in the corresponding gathers, which can be accomplished with sfheadersort.

To produce a 4-D output (for example, a set of gathers in 3-D), try sfintbin3.

10 previous programs of the month:

• sfbox
• sfslant
• sfgrey
• sfhistogram
• sfmf
• sfbin
• sfthreshold
• sfsigmoid
• sfmax1
• sfstolt

Madagascar passes a symbolic mark of one million lines of code. Black Duck Open Hub reports that

In a Nutshell, Madagascar… has had 12,444 commits made by 85 contributors representing 1,098,223 lines of code

Two exciting events are being planned for this summer. The Madagascar School for Advanced Users is being planned for August 8-9, 2015. The school will take place in Qingdao, China, and will be hosted by the China University of Petroleum. Unlike previous Madagascar schools, the intended audience are not beginners but current users of Madagascar who want to learn more about advanced topics (parallel computing; graphical user interfaces; interfaces to C++, Python, and Matlab, etc.) More information is available at https://www.ahay.org/wiki/Qingdao2015. The Working Workshop on 3D Seismic Data Processing is being planned for August 19-22, 2015. The workshop will take place in Houston and will be hosted by Rice University. Unlike previous working workshops, the participations is not limited to Madagascar users. Users of other software packages with interest in seismic field data processing are encouraged to participate. The workshop is being organized by Karl Schleicher, with support of SEG. More information is available at https://www.ahay.org/wiki/SEG3DSeismicProcessingWorkingWorkshopHouston2015-Land3D

sfbox draws a boxed baloon-style label, which is useful for annotating graphics.

The following example from sep/avo/imp annotates several reflectors on a seismic section:

sfbox has a large number of parameters to control the box appearance. The most important are: label= for the text on the label, x0= and y0 for the position of the pointer tip (in Vplot coordinates), xt= and yt= for the relative shift of the label with respect to the pointer tip.

The following example from tccs/timelapse/duri uses xt=0 and yt=0 to hide the pointer under the label.

Selecting proper parameters for the location of the label can be tricky. The task is made interactive by the vpannotate script. vpannotate takes a Vplot file as an input and adds an annotation to it. It can do it in the batch mode (when used with batch=y) or in an interactive mode (when used with batch=n). In the later case, the selected parameters are saved in a text file, which can be used as a parameter file for sfbox (or, alternatively, for vpannotate batch=y).

10 previous programs of the month

• sfslant
• sfgrey
• sfhistogram
• sfmf
• sfbin
• sfthreshold
• sfsigmoid
• sfmax1
• sfstolt
• sfltft

The 1.7 stable release features 21 new reproducible papers and multiple other enhancements including improved tools for parallel computing developed at the Second Working Workshop.

According to the SourceForge statistics, the previous 1.5 stable distribution has been downloaded more than 4,000 times. The top country (with 24% of all downloads) was USA, followed by China, Colombia, Germany, and Brazil. According to Openhub.net (last updated in January 2015), the year of 2014 was a period of a high development activity, with 33 contributors making 1,876 commits to the repository (up 16% from the previous year). Openhub.net says that Madagascar “has a well established, mature codebase maintained by a very large development team with stable year-over-year commits” and estimated 239 man-years of effort (an estimated development cost of $13 million).

A Madagascar school will take place on January 7-8, 2015, in Harbin, China, and will be hosted by the Harbin Institute of Technology (HIT) in conjunction with the International Workshop on Mathematical Geophysics.

More information will be available soon on the school webpage.

“Working workshops” as opposed to “talking workshops” are meetings where the participants work together (possibly divided into pairs or small teams) to develop new software code or to conduct computational experiments addressing a particular problem. Working workshops are a cross between scientific workshops and coding sprints or hackathons common among open-source software communities.

26 participants from 11 different organizations gathered at Rice University at the end of July and beginning of August for the Second Madagascar Working Workshop, hosted by The Rice Inversion Project. The topic of the workshop was parallel high-performance computing. The participants divided into teams of 2-3 people by pairing experienced Madagascar developers with novice users. Each team worked on a small project, creating examples of parallel computing or improving general-purpose tools such as sfmpi, sfomp, and (newly created) sfbatch.

The participants used Stampede, the world’s seventh most powerful supercomputer, provided by the Texas Advanced Computing Center, for their computational experiments.