The software framework called Rts builds upon the precursor, Rt, which is posted elsewhere on this website. To understand Rts it is helpful to keep in mind that our objective is NOT to develop yet another computer program. Various companies, research centres, and private citizens often offer their own tools and programs, developed in various programming languages. Our proposal, an echo from OpenSees and many books on object-oriented programming, is to develop contributions to a distributed library of models and methods. Then we can pick & choose the models and methods we want, when we need them. Rts was created with the C++ programming language using the cross-platform development tool Qt. Soon you will find below examples, tutorials, open-source code, and executables for Windows and Mac.
- To run a reliability analysis with the “CalREL limit-state function” start by storing the file Algebraic_Limit_State_Function.txt on your computer. Then open Rts or do a Clear All if the program is already running. Drag & drop the input file into Rts. To run FORM, right-click on the FORM model and select Run; notice in the input file that you can play around with different line search algorithms. The sampling model is run the same way and you can stop the analysis anytime by changing the Max Samples property.
- To find the root of a one-variable function, i.e., to find the variable value that gives zero function value, store the file Root_Finding.txt on your computer. Then drag & drop it into a clean Rts and run the Root Finding model. Notice that this function can be tricky; some of the line search algorithms get into trouble if the input parameters are off.
- To run a single-variable optimization analysis, i.e., to minimize a function with only one design variable, store the file Single_Variable_Optimization.txt on your computer, then drag and drop it into a clean Rts. Right-click on the optimization model and select run. Notice the delay parameter that slows down the analysis to make it easier to follow the on-screen plotting of each trial point. Also notice the collection of different line search algorithms in the input file.
- To carry out a non-gradient-based optimization with the downhill simplex algorithm, store the file Downhill_Simplex_Optimization.txt on your computer, then drag and drop it into a clan Rts. Right-click on the optimization model and select run. Notice the delay parameter that slows down the analysis to make it easier to follow the on-screen plotting of each simplex. They may be hard to see in the beginning but each simplex is a triangle for this two-variable problem.
- To carry out a gradient-based multi-variable optimization analysis with line searches along selected search directions, then store the file Directional_Line_Search_Optimization.txt on your computer, then drag and drop it into a clan Rts. Right-click on the optimization model and select run. Notice the default line search algorithm, used along each search direction, is the golden section algorithm.
- To carry out a linear elastic structural analysis on a frame (ElasticFrameExample.txt), truss (ElasticTrussExample.txt), or an example that uses elastic shell elements (ElasticCantileverWBeamShellExample.txt) store the file on your computer, then drag and drop it into a clan Rts. Right-click on the structural analysis model and select run. To visualize the structure, right-click on the structural analysis model and select to plot the undeformed or deformed structure. The bending moment diagram (BMD), shear force diagram (SFD), and axial force diagram (AFD) are visualized by right-clicking on the structural analysis model and selecting either BMD, SFD, or AFD. To get values from those diagrams, click anywhere on the plots. Doing that, the selected section is highlighted and the value is given in the output pane. Notice that the view can be rotated by pressing and holding the left mouse button, while moving the mouse in the desired direction. Holding down the right button and moving the mouse will move the structure. To zoom in and out, turn the mouse wheel or use a “pinching” or “spreading” motion on a trackpad.
- To run a reliability analysis with the elastic frame in the previous example, start by storing the file Frame_Reliability.txt on your computer. Then open Rts or do a Clear All if the program is already running. Drag & drop the input file into Rts. You may then right-click on the FORM model and select Run, and thereafter run an importance sampling analysis about the design point that was determined by FORM.