How to do numerical computations?
in [Mathematica]
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From: dh on 1 Apr 2010 07:02 Hi,as you do not give an example I can not be sure. But it sounds like the ever recurring problem of a function being evaluated with symbolic arguments. To ensure that the computations are done numerically, you may e.g. define: f[x_?NumericQ]:=... Daniel On 31.03.2010 12:27, bagarti wrote: > Hello, > Any body please help me, > > I have written some mathematica code which contains some complicated functions.The functions involve integrations and iterations in the intermediate steps. When I run the code it takes a hell lot of time. I do not know what mathematica is doing inside, actually I have another code in fortran that takes only a few minutes to do all the calculations but there are other problems like it dosent work for some parameter range. > > Is there a method in which I can ask mathematica to give me only the numerical values just like any executable program does. > > Thanks. > TaB > -- Daniel Huber Metrohm Ltd. Oberdorfstr. 68 CH-9100 Herisau Tel. +41 71 353 8585, Fax +41 71 353 8907 E-Mail:<mailto:dh(a)metrohm.com> Internet:<http://www.metrohm.com>
From: ingolf.dahl on 1 Apr 2010 07:39 Yes, surely there is such a method, to give you only the numerical values, just avoid symbolic integration and iterations in your procedures. A good start is to specify that your own functions should only take numeric arguments. As example: f[x_?NumericQ] := x^2 will only evaluate for numeric values of the argument. You have to check each step of your code, and understand what Mathematica really does to it. In most practical cases, it is possible to do all necessary symbolic calculations first, check that carefully, and then use the results to streamline the procedures for the numeric values, if you have many different sets of numerical data to evaluate in the same way. But if you want some more detailed help from the MathGroup, it would help tremendously to know more in detail what your code is doing inside. The details are VERY IMPORTANT for the time required, and often there are many ways to obtain the same result, most slow and a few ways very fast. Ingolf Dahl Sweden -----Original Message----- From: bagarti [mailto:bagarti(a)gmail.com] Sent: den 31 mars 2010 12:28 Subject: How to do numerical computations? Hello, Any body please help me, I have written some mathematica code which contains some complicated functions.The functions involve integrations and iterations in the intermediate steps. When I run the code it takes a hell lot of time. I do not know what mathematica is doing inside, actually I have another code in fortran that takes only a few minutes to do all the calculations but there are other problems like it dosent work for some parameter range. Is there a method in which I can ask mathematica to give me only the numerical values just like any executable program does. Thanks. TaB
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