Showing papers on "Source transformation published in 2016"

A Source Transformation via Operator Overloading Method for the Automatic Differentiation of Mathematical Functions in MATLAB

Abstract: A source transformation via operator overloading method is presented for computing derivatives of mathematical functions defined by MATLAB computer programs. The transformed derivative code that results from the method of this article computes a sparse representation of the derivative of the function defined in the original code. As in all source transformation automatic differentiation techniques, an important feature of the method is that any flow control in the original function code is preserved in the derivative code. Furthermore, the resulting derivative code relies solely upon the native MATLAB library. The method is useful in applications where it is required to repeatedly evaluate the derivative of the original function. The approach is demonstrated on several examples and is found to be highly efficient when compared to well-known MATLAB automatic differentiation programs.

ADiJaC -- Automatic Differentiation of Java Classfiles

Abstract: This work presents the current design and implementation of ADiJaC, an automatic differentiation tool for Java classfiles. ADiJaC uses source transformation to generate derivative codes in both the forward and the reverse modes of automatic differentiation. We describe the overall architecture of the tool and present various details and examples for each of the two modes of differentiation. We emphasize the enhancements that have been made over previous versions of ADiJaC and illustrate their influence on the generality of the tool and on the performance of the generated derivative codes. The ADiJaC tool has been used to generate derivatives for a variety of problems, including real-world applications. We evaluate the performance of such codes and compare it to derivatives generated by Tapenade, a well-established automatic differentiation tool for Fortran and C/C++. Additionally, we present a more detailed performance analysis of a real-world application. Apart from being the only general-purpose automatic differentiation tool for Java bytecode, we argue that ADiJaC’s features and performance are comparable to those of similar mature tools for other programming languages such as C/C++ or Fortran.

Togpu: Automatic Source Transformation from C++ to CUDA using Clang/LLVM

Abstract: Parallel processing using GPUs provides substantial increases in algorithm performance across many disciplines including image processing. Serial algorithms are commonly translated to parallel CUDA or OpenCL algorithms. To perform this translation a user must first overcome various GPU development entry barriers. These obstacles change depending on the user but in general may include learning to program using the chosen API, understanding the intricacies of parallel processing and optimization, and other issues such as the upkeep of two sets of code. Such barriers are experienced by experts and novices alike. Leveraging the unique source to source transformation tools provided by Clang/LLVM we have created a tool to generate CUDA from C++. Such transformations reduce obstacles experienced in developing GPU software and can increase efficiency and revision speed regardless of experience. Image processing algorithms specifically benefit greatly from a quick revision cycle which our tool facilitates. This manuscript details togpu, an open source, cross platform tool which performs C++ to CUDA source to source transformations. We present experimentation results using common image processing algorithms. The tool lowers entrance barriers while preserving a singular code base and readability. Providing core tools enhancing GPU developer facilitates further developments to improve high performance, parallel computing.

Programming language features, usage patterns, and the efficiency of generated adjoint code

Abstract: The computation of gradients via the reverse mode of algorithmic differentiation is a valuable technique in modelling many science and engineering applications. This technique is particularly efficient when implemented as a source transformation, as it may use static data-flow analysis. However, some features of the major programming languages are detrimental to the efficiency of the transformed source code. This paper provides an overview of the most common problem scenarios and estimates the cost overhead incurred by using the respective language feature or employing certain common patterns. An understanding of these topics is crucial for the efficiency or even feasibility of adjoint computations, particularly for large-scale numerical simulations, for example, in geosciences. While one cannot hope to cover all effects observable with a given programming language in a given run time environment, the paper aims at providing a reasonable guide for the users of C/C++ and Fortran source transformation tools for algorithmic differentiation.

Translation of Cognitive Models from ACT-R to Constraint Handling Rules

Abstract: Cognitive architectures are used to abstract and simplify the process of computational cognitive modeling. The popular cognitive architecture ACT-R has a well-defined psychological theory, but lacks a formalization of its computational system. This inhibits computational analysis of cognitive models, e.g. confluence or complexity analysis. In this paper we present a source to source transformation of ACT-R models to Constraint Handling Rules (CHR) programs enabling the use of analysis tools for CHR to analyze computational cognitive models. This translation is the first that matches the current abstract operational semantics of ACT-R.

Method and device for editing 3D target model based on 3D source model

Abstract: The invention discloses a method and device for editing a 3D target model based on a 3D source model The method of the invention comprises steps of obtaining a source transformation matrix or a source transformation form when the 3D source model is transformed; obtaining first original coordinates of all vertexes of the 3D target model; determining first new coordinates of all vertexes of the 3D target model when a preset condition is satisfied according to the source transformation matrix and a first original coordinator, wherein the preset condition includes one or more than one following conditions: a first difference between the target transformation matrix and the source transformation matrix of the 3D target model is the smallest, a second difference between a target transformation form of the 3D target model and the source transformation form of the source model is the smallest, and weighted summation of the first difference and the second difference is the smallest The invention discloses a device for editing a 3D target model based on a 3D source model, and the device comprises a first obtaining module, a second obtaining module and a first calculation module The invention provides a method and device for performing edition on the 3D target model on the basis of the 3D source model, which satisfy practical needs of a user

DC -DC source transformation ware topological structure circuit

Abstract: The utility model relates to a DC DC source transformation ware topological structure circuit, including the push -pull type source transformation ware input circuit who connects gradually, transformer and push -pull type source transformation ware output circuit, and connection push -pull type source transformation ware input circuit's serial -type converter circuit, input voltage connects the transformer, push -pull type source transformation ware output circuit's output is connected in the load, input voltage is through push -pull type source transformation ware input circuit, the transformer transmits to push -pull type source transformation ware output circuit, export the DC voltage after the plastic of push -pull type source transformation ware output circuit, the serial -type converter circuit detects output voltage's change, and adjust switching on and end of self in real time, and then adjustment push -pull type source transformation ware input circuit's DC voltage is in order to realize the firm output Compared with the prior art, the utility model discloses satisfy the requirement of exporting the high quality power in the super wide input voltage range, simple structure, easily control, excellent, the low cost of performance

Two -way DCDC source transformation ware

Abstract: The utility model discloses a two -way DCDC source transformation ware aims at providing a circuit long service life, and two -way DCDC source transformation ware that components and parts can non - continuation work has solved the continuation work of all semiconductor device, the technical problem that can make its life reduce, and its technical scheme main points are including having the DC converting circuit that low pressure input and high voltage output held, DC converting circuit is equipped with two, and two DC converting circuit's low -pressure end input and high voltage output end pass through the change over switch reverse parallel connection, have reached and to have carried out the switching use at will, satisfy customer's user demand, have the effect that partial circuit has standby state, the utility model is suitable for a direct -current converter technical field.

A mixed operator overloading and source transformation approach for adjoint cfd computation

Abstract: Adjoint based calculation of sensitivities pertaining to a Computational Fluid Dynamics (CFD) Solver has proven to be a vital tool in tackling large scale problems often found in industrial applications. There are two basic approaches for applying Algorithmic Differentiation (AD) to a CFD solver, namely, Operator Overloading and Source Transformation. Unfortunately, in both cases, it is still necessary to invest a significant amount of manual coding in order to get to an application that performs acceptably in terms of memory consumption and runtime. In this paper reverse mode of AD has been applied to an unstructured pressurebased steady Navier-Stokes solver. We explore the feasibility of combining both kinds of AD approaches to show where and how the advantages of each method can be exploited in order to reach a suitable compromise between performance, simplicity and efficiency. Additionally, we propose a methodology to automate the implementation of an adjoint software in order to minimize work the developer must carry out to produce the desired derivative. We investigate the effectiveness of this approach for relevant flow test cases.

A myriawatt type has source transformation ware that output was selected to alternating current -direct current

Abstract: The utility model provides a myriawatt type has source transformation ware that output was selected to alternating current -direct current, input L and voltage gear selection circuit are connected, divide into two branch roads after the connection, a branch road connected and is constituteed collection altogether by two triodes the amplifier circuit of collection is connected with leakage protection circuit's input more altogether, and another branch road is connected with leakage protection circuit's input after connecting rectification filter circuit again, zero line N is connected with leakage protection circuit's input zero line after connecting the alternating current -direct current switching circuit. This source transformation utensil is equipped with friendship, the compatible input function of direct current, and input voltage range is wide moreover, and it is wide to exchange input voltage range, can be 220Vac or 380Vac and input, can set for stable alternating current and the required multiple direct current of user of output through the switch. Can be applicable to the occasion within 10000 output made of baked clay, can show the output voltage data when the branch road inserts digital display module, it is more convenient to use.

Five kilowatts of types have source transformation ware that output was selected to alternating current -direct current

Abstract: The utility model provides a five kilowatts of types have source transformation ware that output was selected to alternating current -direct current, input L and voltage gear selection circuit are connected, divide into two branch roads after the connection, a branch road connected and is constituteed collection altogether by two triodes the amplifier circuit of collection is connected with leakage protection circuit's input more altogether, and another branch road is connected with leakage protection circuit's input after connecting rectification filter circuit again, zero line N is connected with leakage protection circuit's input zero line after connecting the alternating current -direct current switching circuit. This source transformation utensil is equipped with friendship, the compatible input function of direct current, and input voltage range is wide moreover, and it is wide to exchange input voltage range, can be 220Vac or 380Vac and input, can set for stable alternating current and the required multiple direct current of user of output through the switch. Can be applicable to the occasion within 5000 output made of baked clay, can show the output voltage data when the branch road inserts digital display module, it is more convenient to use.

Interfacing OpenAD and Tapenade

Abstract: Development of a capable algorithmic differentiation (AD) tool requires large developer effort to provide the various flavors of derivatives, to experiment with the many AD model variants, and to apply them to the candidate application languages. Considering the relatively small size of the academic teams that develop AD tools, collaboration between them is a natural idea. This collaboration can exist at the level of research ideas as well as tool development. This work describes the interoperation of two source to source transformation AD tools OpenAD and Tapenade. The interoperative pipeline uses the parsing and source analysis capabilities of Tapenade with the transformation algorithms of OpenAD.