Analysis of Structures - Baustatik-Info-Server

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Page 28Analysis of Structures - WS10/11The return values are packed into a tuple (see section 2.10.1). The tuple is used in the set order. So wecan use it for the string format. Reordering is not needed. The output into the console window is thefollowing for the selected test example.x1 = -0.000000+(2.000000i), x2= -0.000000+(-2.000000i),next> info: Complex case of the quadratic problem.2.9 FunctionsA function is a callable type. A function starts with the def command. The parameter list succeeds thefunction name and consists of names separated by commas. The return of return values is optional. Anice example to study cases of a solution and their specific return values is discussed in section 2.8.def (Parameter list):Code Blockreturn The following code shows a special version of the abs function. The data type is checked first. Only int,long or float type are senseful supported. We check the type with the type function. The type functionreturns a type object. Within the function we check the object member __name__. If the type is notsupported, a error string is returned. If the type is supported, the return value is return. The callingprogram checks the return values type using the object name (int, long and float).Abs Function with Type Checking# declaring our version of an abs functiondef MyAbs(x):# process only sensful data types# here we use the type class member name# to check the data typet = type(x). nameif t != ’int’ and t != ’long’ and t != ’float’:return "Error: Type ’%s’ is not allowed." %t# if data type ok change sign if necessaryif x < 0.: return -xreturn x# input sectiony = -4 # test 1# y = "hello" # test 2# function callz = MyAbs(y)# get return typeE. Baeck
2.9. FUNCTIONS Page 29t = type(z)if t == str:print zelse:print "Absolute Value of %f = %f" % (y,z)# second version to check the type# print error message# print resultEnd of CodingThe following example shows, how to pass a function asa functions parameter. Within the Newton’s algorithma root of an equation should be calculated. So we haveto specify the function of interest. This function can beconsidered as an input parameter. This function nameis passed to the derivative calculator and to the newtonmain routine. Further we see, that it’s recommended touse standard parameter, to configure the algorithm. Weintroduce the precision parameter e, which sets up thethreshold for a zero compare. Further we need the stepwidth to calculate the derivative of the function of ourinterest.Figure 2.3: Scheme of the Newton AlgorithmThe derivative - it’s called fs in the code - is calculated numerical as follows.f ′ (x) = dfdx ≈ (f (x + h 2 ) − f (x − h 2 ) )/h(2.9)The Newton scheme can be described as follows.x i+1 = x i − f (x)f ′ (x)(2.10)There are three possible situations to handle within the iteration loop.• The function value is vanishing with respect to our selected precision. The iteration loop will bebroken and the found result is passed back to the caller.• The slope of the function is vanishing. This situation can not be handled by the simple iterationscheme. The iteration will be broken with an error message.• During the iteration each cycle is counted. So the iteration loop will be broken, if the maximumavailable iterations are reached. The actual values and an error message is passed bake to the caller.The code consists of the following functions.• Myf, the function of our interest.• fs, the function which calculates the slope of a given function numerically.2.12.2011
Page 1: Analysis of StructuresBook of Examp
Page 5 and 6: CONTENTS Page 1A.1.5 Moments of Ine
Page 7: Part IProgramming with Python3
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Page 71 and 72: 4Some Aspects and IntroductionIn th
Page 73 and 74: 4.3. A MODELING CHAIN Page 694.3 A
Page 75 and 76: 4.4. A LITTLE INTERACTIVE WARM UP E
Page 77 and 78: 5Scripts and ExamplesIn this chapte
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5.1. 3 TRUSSES SCRIPT Page 79myJob.
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5.2. U PROFILE SCRIPT Page 81prjnam
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5.2. U PROFILE SCRIPT Page 89Figure
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Part IIIAppendix95
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Index:, 28AbaqusabaqusMacros, 73Bas
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