Sun Workstations Research Articles

Linear Statics Analysis of the Connecting Rod of a Certain Type of Continuous Mill with Mechanics Properties

The connecting rod of a certain type of continuous mill early produces crackle,cannot work,hindering the production.The authors are entrusted with the 3D Finite Element Analysis (FEA) of the connecting rod.On SUN workstation,utilizing the large scale Integrated-Design Engineering Analysis Software,I-DEAS,the authors have constructed accurate 3D solid model of the connecting rod,set up effective 3D FEA model,found the solution of several kinds of law of stress distribution and deformation,reached valuable conclusions.

Load balancing and optimization of distributed proximity effect correction on a temporally heterogeneous cluster

Grayscale electron-beam lithography is a technique widely used in transferring three-dimensional structures onto the resist layer or substrate. The proximity effect caused by electron scattering in the resist imposes a severe limitation on the ultimate spatial resolution attainable by e-beam lithography. Therefore, correction of the proximity effect is essential particularly for the fine-feature, high-density circuit patterns. However, the proximity effect correction is very time-consuming due to the intensive computation required in the correction procedure and a large size of circuit data to be processed. Hence, it is an ideal candidate for distributed computing where the otherwise-unused CPU cycles of a number of computers on a network (cluster) can be efficiently utilized. One of the characteristics of such a cluster is its heterogeneity, i.e., the available computing power varies with computer and/or time. This variation may degrade the performance of distributed computing significantly. In this paper, efficient distributed implementations of grayscale proximity effect correction on a temporally heterogeneous cluster are described with the main emphasis on static and dynamic load balancing schemes and their optimization through effective task partitioning methods. The experimental results obtained on a cluster of Sun workstations shared by multiple users are presented with detailed discussion.

TIERRAS: A package to simulate high energy cosmic ray showers underground, underwater and under-ice

Abstract In this paper we present TIERRAS, a Monte Carlo simulation program based on the well-known AIRES air shower simulations system that enables the propagation of particle cascades underground, providing a tool to study particles arriving underground from a primary cosmic ray on the atmosphere or to initiate cascades directly underground and propagate them, exiting into the atmosphere if necessary. We show several cross-checks of its results against CORSIKA, FLUKA, GEANT and ZHS simulations and we make some considerations regarding its possible use and limitations. The first results of full underground shower simulations are presented, as an example of the package capabilities. Program summary Program title: TIERRAS for AIRES Catalogue identifier: AEFO_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEFO_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 36 489 No. of bytes in distributed program, including test data, etc.: 3 261 669 Distribution format: tar.gz Programming language: Fortran 77 and C Computer: PC, Alpha, IBM, HP, Silicon Graphics and Sun workstations Operating system: Linux, DEC Unix, AIX, SunOS, Unix System V RAM: 22 Mb bytes Classification: 1.1 External routines: TIERRAS requires AIRES 2.8.4 to be installed on the system. AIRES 2.8.4 can be downloaded from http://www.fisica.unlp.edu.ar/auger/aires/eg_AiresDownload.html . Nature of problem: Simulation of high and ultra high energy underground particle showers. Solution method: Modification of the AIRES 2.8.4 code to accommodate underground conditions. Restrictions: In AIRES some processes that are not statistically significant on the atmosphere are not simulated. In particular, it does not include muon photonuclear processes. This imposes a limitation on the application of this package to a depth of 1 km of standard rock (or 2.5 km of water equivalent). Neutrinos are not tracked on the simulation, but their energy is taken into account in decays. Running time: A TIERRAS for AIRES run of a 10 20 eV shower with statistical sampling (thinning) below 10 12 eV and 0.2 weight factor (see [1]) uses approximately 1 h of CPU time on an Intel Core 2 Quad Q6600 at 2.4 GHz. It uses only one core, so 4 simultaneous simulations can be run on this computer. Aires includes a spooling system to run several simultaneous jobs of any type.

Nonlinear inversion of geoelectric data acquired across 3D objects using a finite-element approach

We introduce a new finite-element-based scheme for the fast nonlinear inversion of large 3D geoelectric data sets acquired around isolated objects or across the earth’s surface. The principal novelty of this scheme is the combination of a versatile finite-element approach with (1) a method involving minimization of an objective function using a conjugate-gradient algorithm that includes an adjoint-field technique for efficiently establishing the objective-function gradient and (2) parabolic interpolation for estimating suitable inversion step lengths. This scheme is capable of handling large volumes of data acquired using diverse electrode configurations located around or across 3D structures. Only three solutions to the forward problem are required for each iteration. Computation of the Jacobian matrix, which might require computers with a large amount of memory, is not necessary. To minimize artificial irregularities in the inverted models, particularly near the electrodes, we smooth the model parametersafter each iteration. By including the influence of a reference model in the objective function, a priori information can be incorporated in the inversion process. Our new scheme is tested successfully on synthetic data generated for current and potential electrodes distributed around the surface of a complex object of finite extent. We also demonstrate the utility of the new scheme on geoelectric data acquired around a laboratory-scale object. Tomographic inversion of the 52,272 simulated voltage values in terms of an 8775-element model requires less than 45 minutes on a relatively slow Sun workstation. For the inversion of the 1016 observed voltage values in terms of an 81,480-element model, approximately 60 minutes of computer time is required. The rapid and flexible inversion scheme opens up new possibilities for resistivity imaging in geology, hydrology, engineering, nondestructive testing, and even biology and medicine, fields of study in which finite-element models are already used to represent complicated targets.

ACO-Steiner: Ant Colony Optimization Based Rectilinear Steiner Minimal Tree Algorithm

The rectilinear Steiner minimal tree (RSMT) problem is one of the fundamental problems in physical design, especially in routing, which is known to be NP-complete. This paper presents an algorithm, called ACO-Steiner, for RSMT construction based on ant colony optimization (ACO). An RSMT is constructed with ants' movements in Hanan grid, and then the constraint of Hanan grid is broken to accelerate ants' movements to improve the performance of the algorithm. This algorithm has been implemented on a Sun workstation with Unix operating system and the results have been compared with the fastest exact RSMT algorithm, GeoSteiner 3.1 and a recent heuristic using batched greedy triple construction (BGTC). Experimental results show that ACO-Steiner can get a short running time and keep the high performance. Furthermore, it is also found that the ACO-Steiner can be easily extended to be used to some other problems, such as rectilinear Steiner minimal tree avoiding obstacles, and congestion reduction in global routing.

A real-time intelligent multiple fault diagnostic system

Modern manufacturing systems and their failure modes are very complex, and efficient fault diagnosis is essential for higher productivity. However, traditional fault diagnostic systems that perform sequential fault diagnosis can fail during diagnosis when fault propagation is very fast. This paper describes a real-time intelligent multiple fault diagnostic system (RIMFDS). This system deals with multiple fault diagnosis, and is based on multiprocessing by using a strata hierarchical artificial neural network (SHANN). If another fault occurs while an existing symptom is being diagnosed, the corresponding diagnosis module is triggered, and the fault diagnosis module of the new faulty unit begins to diagnose the faults in real time. RIMFDS can diagnose multiple faults with fast fault propagation and complex physical phenomena. The system consists of two main parts. One is a personal computer for remote signal generation and transmission, and the other is a host system for multiple fault diagnosis. The signal generator generates various faulty signals and image information and sends them to the host. The host has various modules and agents for efficient multiple fault diagnosis. A SUN workstation is used as a host for multiple fault diagnosis and graphic representation of the results.

Parallelising the MARS15 code with MPI for shielding applications

The MARS15 Monte Carlo code capabilities to deal with time-consuming deep penetration shielding problems and other computationally tough tasks in accelerator, detector and shielding applications, have been enhanced by a parallel processing option. It has been developed, implemented and tested on the Fermilab Accelerator Division Linux cluster and network of Sun workstations. The code uses a message passing interface MPI. It is scalable and demonstrates good performance. The general architecture of the code, specific uses of message passing and effects of a scheduling on the performance and fault tolerance are described.

Multi-objective optimization of high-speed milling with parallel genetic simulated annealing

In this paper, the optimization of multi-pass milling has been investigated in terms of two objectives: machining time and production cost. An advanced search algorithm—parallel genetic simulated annealing (PGSA)—was used to obtain the optimal cutting parameters. In the implementation of PGSA, the fitness assignment is based on the concept of a non-dominated sorting genetic algorithm (NSGA). An application example is given using PGSA, which has been used to find the optimal solutions under four different axial depths of cut on a 37 SUN workstation network simultaneously. In a single run, PGSA can find a Pareto-optimal front which is composed of many Pareto-optimal solutions. A weighted average strategy is then used to find the optimal cutting parameters along the Pareto-optimal front. Finally, based on the concept of dynamic programming, the optimal cutting strategy has been obtained.

Optimization of Spacecraft Thruster Management Function

Original mathematical algorithms related to spacecraft thruster selection problem have been designed, implemented and tested covering both non-real-time and real-time aspects. The algorithms are based on a new computational routine to synthesize linear programming problem optimal solution when the right side of linear constraints varies. Real-time phase software requires from 0.05 ms through to 0.21 ms to be executed on a SUN workstation with a 550 MHz UltraSparc processor. The size of memory to store real-time computations data varies from 26 through to 390 KB depending on the number of thrusters (up to 28 thrusters were tested). The user is provided with flexibility to select the option, which better meets specific criteria and constraints such as execution time, accuracy of the optimal solution (at the expense of execution time or memory), etc. In addition to C -code implementation, the module (intended for real time) could be implemented as a standard SIMULINK library block and can be integrated with different simulators for test purposes. The implemented software demonstrated effectiveness and robustness of the designed algorithms both in open- and closed-loop tests including various maneuvers of a spacecraft.

FROSTY: A program for fast extraction of high-level structural representation from circuit description for industrial CMOS circuits

This paper presents FROSTY, a computer program for automatically extracting the high-level structural representation of a large-scale digital CMOS circuit from its transistor-level netlist and a library of subcircuit descriptions. To handle the complexity and diversity of industrial circuits, FROSTY combines traditional structural recognition and pattern matching methods into a two-step extraction process. First, logic structures based on channel-connected-components are recognized from a circuit netlist and from all library subcircuits, and are condensed into “macro devices” or called logic gates. This leads to hybrid netlists that contain the recognized logic gates and remaining transistors. Then annotated graphs representing the connectivity and properties of logic gates and remaining transistors are constructed. Compared to transistor-level netlists, these hybrid graphs are much smaller in size, more distinguishable in structure, and are thus more suitable for labeling-based pattern matching. An efficient pattern matching algorithm is then applied to extract the high-level structural representation from these condensed circuit graphs. FROSTY has demonstrated to be orders of magnitude faster than the pattern matching-based extraction program SubGemini, and can extract entire industrial designs with several hundreds of thousands of transistors in a few minutes on a modern Sun workstation. Furthermore, the FROSTY algorithm scales well with the size of a circuit.

Proteome Changes in Ovarian Epithelial Cells Derived from Women with BRCA1 Mutations and Family Histories of Cancer

Malignant transformation of the ovarian surface epithelium (OSE) accounts for most ovarian carcinoma. Detection of preneoplastic changes in the OSE leading to overt malignancy is important in prevention and management of ovarian cancer. We identified OSE proteins with altered expression derived from women with a family history (FH) of ovarian and/or breast cancer and mutations in the BRCA1 tumor suppressor gene. Proteins from SV-40-transformed FH-OSE cell lines and control OSE lines derived from women without such histories (non-family history) were separated by two-dimensional PAGE. Gels were analyzed, a protein data base was created, and proteins were characterized according to their molecular weight, isoelectric point, and relative abundance. Mass spectrometry was performed on tryptic protein digests, and data bases were searched for known proteins with the same theoretical tryptic peptide masses. Several proteins showed altered expression in the FH-OSE cells. Beta-tubulin and to a lesser extent ubiquitin carboxyl-terminal hydrolase and glyoxalase 1 appeared to be up-regulated. In contrast, proteins suppressed in FH lines include the 27-kDa heat shock protein, translationally controlled tumor protein, and several proteins associated with actin modification such as actin prepeptide, F-actin capping protein alpha subunit, and cofilin. Sequencing of several cofilin gel spots revealed phosphorylation of serine 3, a post-translational modification associated with decreased actin binding and cytoskeletal reorganization. Two-dimensional Western blots probed with cofilin antibody showed multiple protein spots with isoelectric points of 6-9 pH units. Blots of one-dimensional gels showed a significant reduction in cofilin expression in three FH lines when compared with three non-family history lines (p < or = 0.05). Identification of these and other OSE proteins may be useful in detecting changes suggestive of increased risk of developing preneoplastic disease and defining the possible role(s) of the BRCA1 gene in regulation of OSE cell function.

A comparative study of explicit group iterative solvers on a cluster of workstations

In this paper, a group iterative scheme based on rotated (cross) five-point finite difference discretisation, i.e. the four-point explicit decoupled group (EDG) is considered in solving a second order elliptic partial differential equation (PDE). This method was firstly introduced by Abdullah [“The four point EDG method: a fast poisson solver”, Int. J. Comput. Math., 38 (1991) 61–70], where the method was found to be more superior than the common existing methods based on the standard five-point finite difference discretisation. The method was further extended to different type of PDE's, where similar improved results were established [Ali, N.H.M., Abdullah, A.R. Four Point EDG: A Fast Solver For The Navier–Stokes Equation, M.H.Hamza (ed.) Proceedings of the IASTED International Conference on Modelling Simulation And Optimization, Gold Coast, Australia, May 6–9 (1996) (CD Rom-File 242-165.pdf), ISBN: 0-88986-197-8; Ali, N.H.M., Abdullah, A.R. New Parallel Point Iterative Solutions For the Diffusion-Convection Equation Proceedings of the International Conference on Parallel and Distributed Computing and Networks Singapore, Aug. 11–13 (1997) 136–139; Ali, N.H.M., Abdullah, A.R. “New rotated iterative algorithms for the solution of a coupled system of elliptic equations” Int. J. Comput. Math. 74 (1999) 223–251]. These new iterative algorithms had been developed to run on the Sequent Balance, a shared memory parallel computer [A.R. Abdullah, N.M. Ali, The Comparative Study of Parallel Strategies For The Solution of Elliptic PDE's Parallel Algorithms and Applications Vol. 10 (1996) 93–103; Ali, N.H.M., Abdullah, A.R. “Parallel four point explicit decoupled group (EDG) method for elliptic PDE's” Proceedings of the Seventh IASTED/ISMM International Conference on Parallel and Distributed Computing and Systems (1995) 302–304 (Washington DC); Ali, N.H.M., Abdullah, A.R. New Parallel Point Iterative Solutions For the Diffusion-Convection Equation Proceedings of the International Conference on Parallel and Distributed Computing and Networks, Singapore, Aug. 11–13 (1997) 136–139; Yousif, W.S., Evans, D.J.“Explicit decoupled group iterative methods and their parallel implementations” Parallel Algorithms and Applications 7 (1995) 53–71] where they were shown to be suitable to be implemented in parallel. In this work, the four-point group algorithm was ported to run on a cluster of Sun workstations using a parallel virtual machine (PVM) programming environment together with the four-point explicit group (EG) method [Evans, D.J., Yousif, W.S. “The implementation of the explicit block iterative methods on the balance 8000 parallel computer” Parallel Computing 16 (1990) 81–97]. We describe the parallel implementations of these methods in solving the Poisson equation and the results of some computational experiments are compared and reported. rosni@cs.usm.my kokjl@hotmail.com

DEQUE: querying the deep web

In this paper, we present a system called DEQUE ( Deep W Eb QUery Syst Em) for modeling and querying the deep Web. We propose a data model for representing and storing HTML forms, and a web form query language called DEQUEL for retrieving data from the deep Web and storing them in the format convenient for additional processing. Our system is able to query forms (single and consecutive) with input values from relations as well as from result pages (results of querying web forms). We present a novel approach in modeling of consecutive forms and introduce the concept of the super form. A prototype system has been implemented on a SUN workstation working under Solaris 2.7 using Perl version 5.005_2 and employing MySQL (version 3.23.49) DBMS as the data storage.

Differential evolution – an easy and efficient evolutionary algorithm for model optimisation

Recently, evolutionary algorithms (encompassing genetic algorithms, evolution strategies, and genetic programming) have proven to be the best general method for the optimisation of large, difficult problems, including agricultural models. Differential evolution (DE) is one comparatively simple variant of an evolutionary algorithm. DE has only three or four operational parameters, and can be coded in about 20 lines of pseudo-code. Investigations of its performance in the optimisation of a challenging beef property model with 70 interacting management options (hence a 70-dimensional optimisation problem) indicate that DE performs better than Genial (a real-value genetic algorithm), which has been the preferred operational package thus far. Despite DE's apparent simplicity, the interacting key evolutionary operators of mutation and recombination are present and effective. In particular, DE has the advantage of incorporating a relatively simple and efficient form of self-adapting mutation. This is one of the main advantages found in evolution strategies, but these methods usually require the burdening overhead of doubling the dimensionality of the search-space to achieve this. DE's processes are illustrated, and model optimisations totaling over two years of Sun workstation computation are presented. These results show that the baseline DE parameters work effectively, but can be improved in two ways. Firstly, the population size does not need to be overly high, and smaller populations can be considerably more efficient; and second, the periodic application of extrapolative mutation may be effective in counteracting the contractive nature of DE's intermediate arithmetic recombination in the latter stages of the optimisations. This provides an escape mechanism to prevent sub-optimal convergence. With its ease of implementation and proven efficiency, DE is ideally suited to both novice and experienced users wishing to optimise their simulation models.

DATA INTEGRATION FROM THE SCIENTIFIC COMMUNITY AND CTBTO: THE ITALIAN NDC EXPERIENCE WITH ANTELOPE

The Italian Institute for Geophysics and Volcanology (INGV) is hosting the Italian National Data Center (INDC) for the Comprehensive Nuclear Test-Ban-Treaty Organization (CTBTO). One of the main tasks associated with the planned verification system of CTBTO is the production of a bulletin of global seismic activity. Such a bulletin will facilitate the efforts of state parties to monitor events and identify underground explosions that might be conducted in violation of the Treaty. To accomplish this task, a bulletin must cover the entire globe with a minimum threshold and location accuracy specified by the protocol of the treaty. The preparation of the CTBTO networks—the International Monitoring System (IMS)—and of the related International Data Centre (IDC) is ongoing. An important aspect of this preparation process is the evaluation of the quality of all the IDC products, so as to be able to optimize the efficiency and effectiveness of the overall system. Moreover, the tasks of a typical NDC include a mixture of the following: monitoring of the status of the IMS/IDC, contributing to further refinement of the IDC processing, and evaluating the data provided by the IDC. Therefore a NDC must have the capability to process raw data provided by the IMS, combine IMS data with additional data to achieve higher accuracy, and discriminate the nature of an event. As a contribution to the evaluation task, the technical Working Group B (WGB) of CTBTO has suggested comparison between the bulletins produced by IDC and regional/local networks. The Italian National Data Center has been collecting data since September 2002 from several regional networks in the European-Mediterranean region. The data are collected, processed, stored, and exchanged by the Antelope software package installed on Sun workstations. Previous SRL reports have discussed the use of the Antelope software in comparison with other packages. Following the contributions …

The design and implementation of a runtime system for graph-oriented parallel and distributed programming

Graph has been widely used in modeling, specification, and design of parallel and distributed systems. Many parallel and distributed programs can be expressed as a collection of parallel functional modules whose relationships can be defined by a graph. Often, the basic functions of communication and coordination of the parallel modules are expressed in terms of the underlying graph. Furthermore, parallel/distributed graph algorithms are used to realize various control functions. To facilitate the implementation of these algorithms, it is desirable to have an integrated approach that provides direct support for efficient operations on graphs. We have proposed a graph-oriented programming model, called GOP, which aims at providing high-level abstractions for configuring and programming cooperative parallel processes. GOP enables the programmer to configure the logical structure of a distributed program by using a logical graph and to write the program using communications and synchronization primitives based on the logical structure. In this paper, we describe the design and implementation of a portable run-time system for the GOP framework. The runtime system provides an interface with a library of programming primitives to the low-level facilities required to support graph-oriented communications and synchronization. The implementation is on top of the parallel virtual machine in a local area network of Sun workstations. We focus our discussion on the following four aspects: the software architecture, including the structure of runtime system and interfaces between user programs and the runtime kernel; graph representation; implementation of graph operations; and performance of the run-time in terms of the implementation of graph-oriented communications.

Parallel, multigrain iterative solvers for hiding network latencies on MPPs and networks of clusters

Parallel iterative solvers are often the only means of solving large linear systems and eigenproblems. However, these solvers are usually implemented in a fine-grain manner and can incur significant performance penalties due to synchronization overheads on large MPPs. This problem is exacerbated in clusters of workstations (COWs) and SMPs that are interconnected via a hierarchy of networks. In this paper, we describe a novel scheme for hiding the synchronization overheads, and thus improving scalability, of block iterative solvers that employ a correction equation through an inner iterative method. Block methods are not only robust in the presence of eigenvalue multiplicities and multiple right-hand sides, but provide better latency tolerance by performing more floating-point operations between synchronizations. We take a different approach to inducing latency tolerance by increasing the granularity at which the correction equation is solved for each block vector. This is accomplished by splitting the processors into smaller subgroups which are then used to solve the correction for each block vector concurrently. The rest of the algorithm is still performed in fine grain. We call this combination of fine and coarse-grain parallelism multigrain parallelism. We implemented a multigrain, block Jacobi–Davidson algorithm for computing the extreme eigenvalues of a symmetric matrix. We obtained improvements of 45–50% over both the block and non-block implementations of the fine-grain method when testing on an IBM SP and on a collection of clusters of Sun workstations.

Efficient construction of multibit tries for IP lookup

Srinivasan and Varghese (see ACM Trans. Comput. Syst., p.1-40, 1999) have proposed the use of multibit tries to represent routing tables used for Internet (IP) address lookups. They propose dynamic programming algorithms to determine the strides of optimal multibit fixed-stride and variable-stride tries. We improve on these algorithms by providing alternative dynamic programming formulations for both fixed- and variable-stride tries. While the asymptotic complexities of our algorithms are the same as those for the corresponding algorithms of Srinivasan and Varghese, experiments using real IPv4 routing table data indicate that our algorithms run considerably faster. Our fixed-stride trie algorithm is two to four times faster on a SUN workstation and 1.5 to three times faster on a Pentium IV PC. On a SUN workstation, our variable-stride trie algorithm is between two and 17 times faster than the corresponding algorithm of Srinivasan and Varghese; on a Pentium IV PC, our algorithm is between three and 47 times faster. An added feature of our variable-stride trie algorithm is the ability to insert and delete prefixes taking a fraction of the time needed to construct an optimal variable-stride trie from scratch.

Efficient very large scale integration power/ground network sizing based on equivalent circuit modeling

We present an efficient method of minimizing the area of power/ground (P/G) networks in integrated circuit layouts subject to reliability constraints. Instead of directly sizing the original P/G network extracted from a circuit layout, as done previously, the new method first constructs a reduced but electrically equivalent P/G network. Then the sequence of linear programming method is applied to optimize the reduced network. The solution of the original network is then backsolved from the optimized reduced network. The new method exploits the regularities in the P/G networks to reduce the complexities of P/G networks. Experimental results show that the sizes of reduced networks are typically significantly smaller than that of the original networks. The resulting algorithm is fast enough that P/G networks with more than one million branches can be sized in a few minutes on modern Sun workstations.

CG3TOOL: an interactive computer program to process Scintrex CG-3/3M gravity data for high-resolution applications

A newly developed interactive computer program, CG3TOOL, has been dedicated to the processing of the gravity data acquired by the Scintrex CG-3/3M automated gravity meter. The aim of CG3TOOL is two fold: to allow for an objective evaluation of Scintrex data and to provide a higher resolution in data reductions than those computed in real time by the microprocessor-controlled instrument. The program reads the gravity data acquired in either field or cycle mode (field surveys and continuous recordings, respectively) and then downloaded from the meter to a PC computer. The processing tasks are divided into two successive levels. Level 1 is dedicated to the reduction of the daily data files by applying standard or accurate corrections (earth tide, instrumental drift, atmospheric pressure). The precise corrections are performed up to the microGal (μGal) level, in accordance with the specifications of high-resolution surveys. Level 2 contains a series of processing tools (including network adjustment, anomaly computation, and gravity meter calibration) that will precisely compute and adjust the gravity values with error estimates. The interactive procedures and the program output (plot and text files) have been designed to ease data handling and archiving as well as to provide useful information for future purposes of data interpretation or modeling. CG3TOOL was developed in a standard C language for Unix Sun workstations and uses the standard graphical and mathematical Generic Mapping Tools (GMT) free library, available from the web. The objectives and principles of the computer program are presented below along with corresponding examples of the main processing tasks applied to observed data.