Dynamic linked libraries

The Evaluation system is a Windows based open system through DLL, Dynamic Link Library, which provides great flexibility in evaluation and presentation of data. It also makes it possible to customise evaluation and images for special applications The time gates can be set after testing and there is a 256 colour range for amplitude. The software include FFT -facilities which enables measurements on used probes for parameters such as center frequenzy and bandwidth. 

When embedded in decision support systems (usually in a Windows environment), LP solvers typically receive input data from a program written in C or Visual Basic and are often in the form of dynamic link libraries (DLLs). Most of today s LP solvers are available as DLLs. 

Scatter search has been implemented in software called OPTQUEST (see www.opttek.com). OPTQUEST is available as a callable library written in C, which can be invoked from any C program, or as a dynamic linked library (DLL), which can be called from a variety of languages including C, Visual Basic, and Java. The callable library consists of a set of functions that (1) input the problem size and data, (2) set options and tolerances, (3) perform steps 1 through 3 to create an initial reference set, (4) retrieve a trial solution from OPTQUEST to be input to the improvement method, and (5) input the solution resulting from the improvement method back into OPTQUEST, which uses it as the input to step 7 of the scatter search protocol. The improvement method is provided by the user. We use the term improvement loosely here because the user can simply provide an evaluation of the objective and constraint functions. 

For C programmers, it is possible to write programs in C, compile them into dynamic link libraries and use these from Excel, normally via VBA. This has advantages for numerically intensive calculations such as PCA on large datasets which are slow in VBA but which can be optimised in C. A good strategy is to employ Excel as die front end, then VBA to communicate witit die user and also for control of dialog boxes, and finally a C DLL for the intensive numeric calculations. 

Conflict/compatibility testing should be conducted in order to ensnre that applications are able to coexist on the client PC. A typical example of conflict/incompatibihty is where two applications installed on a client PC utilize the same Dynamic Link Library (DLL) files but different versions. Controls should be implemented to prevent two applications using the same DLL files or to evaluate and test the impact of an apphcation using a version of a DLL for which it was not designed. 

Numerous other DLL (dynamic link library) files are also required, but usually the lack or corruption of one of these will simply produce a non-critical error, while the absence of WIN.COM or HAL.DLL will cause the system to be nonfunctional. 

Dynamic Link Library (DLL) files Windows component files that contain small... 

As indicated above, the ChemApp programmers library (in the form of a Dynamic Link Library, DLL) has been used to form the thermodynamic backbone of SimuSage. The general concept is represented in Figure 3. The ChemApp library permits the easy use of full complex equilibrium calculations within a software by way of a set of interface routines. These interface routines are used to... 

In the context of IMPROVE, commercial and third-party tools had to be integrated into the engineering design environment. They were mostly equipped with a COM interface (e.g. Aspen Plus, Comos PT, or Documentum). Hence, our approach concentrated on COM (Component Object Model [846])" . COM follows the object-oriented paradigm, i.e. COM components represent subsystems, consisting of a set of classes including attribute and method definitions, relationships between classes, and a set of interfaces to access the subsystem. For every COM interface, fixed by standardization, a textual description is available in form of a so-called type library or a dynamic link library, respectively. 

VBA is functionally rich and flexible. It has the ability to use ActiveX/COM dynamic link libraries, and the more recent versions support class modules. 

Figure 6.37 shows the dialog box in Excel for comparison. One of the fundamental distinctions between these mechanisms in Mathcad and Excel is that Excel list contains both built-in and user-defined functions. User functions in Mathcad can appear in the Insert Function dialog box only if transformed into built-in functions in the form of a Dynamic Link Library (DLL). 

The second reason for imperfect use of Mathcad capabilities is from a group of Mathcad users who do not use units justifying such decision with the idea that their quantities expressed in the basic units of one unit system (for example, in SI) and they have no difficulties with unit conversion. This reinforcing this notion is that without units Mathcad worksheets are simpler to compile to environment of the programming languages (such as C++, Fortran, etc), for conversion of customized functions into built-in DLLs (Dynamic-linked Libraries). The third reason is of major importance. It is connected with some peculiarities and limitations of tmit tool that cause a skilled user to extract units from a worksheet, almost finished, and turn them into comments instead of... 

---