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#### File Exchange>Category:Mathematics>   Finding Roots of Equations

 Author: OriginLab Technical Support Date Added: 11/6/2003 Downloads: 1676 Last Update: 11/6/2003 Total Ratings: 2 File Size: 87461 Bytes Average Rating: File Name: Find_Roots.opj Created Using: Origin 7.5 File Version: 1.0 Working Versions: 7.5 License: Free
 Summary: This Origin Project file can be used to find roots of equations. This project needs Origin version 7.5 or higher. Description: This is an Active Origin Project - it uses a new feature of Origin 7.5 that allows attaching files to an OPJ. This OPJ has an Origin C file, a worksheet template, and a graph template attached to it. How to find roots of equations: ------------------------------- You need to issue a command from the script window, where you specify the equation and the x range in which to find roots. If roots are found for the equation in the specified x range, a graph of the equation is created and the roots are marked on the graph. A hidden worksheet is also created that contains the data plotted in the graph. The roots are also reported to the script window. For example, to find roots of the equation: sin(x)/x = 0.1 in the x range of -10 to 10, enter the following command in the script window and press the Enter key: find_roots "sin(x)/x-0.1" -10 10 Note that 1> The equation has to be written in the form f(x) = 0 and you then enter only the f(x) part in the command. 2> Only one variable is supported and it has to be named x. 3> The equation has to be entered with quotes around it. 4> In your equation, you can use any mathematical function that is part of the ANSI C function set, or is part of the Origin C function set. For example, there is no sec(x) in ANSI C. So you will need to write that as 1/cos(x). Algorithm for finding roots: ---------------------------- This sample uses a very simple algorithm, as follows: a> In the x range specified by user, all intervals that contain a sign change in the function are first located. b> Each such interval is checked to see if the function is monotonic within that interval. c> In each of the intervals where the function is monotonic, a bisectional root search is performed: The interval is successively divided in half until either the maximum number of iterations is exceeded, or the root is found to a preset precision. The max iterations and root precision are set in the Origin C code as constants, and can be changed. To view the code associated with this OPJ, go to Code Builder (menu item: View|Code Builder) and look at the Origin C file called find_roots.c in the Project branch of the Code Builder workspace tree.
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Reviews:

 Rated by: fandahan1987 Date: (2/22/2012 1:49:47 AM)
 Rated by: reza Date: (11/16/2003 10:51:25 PM)

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