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<div style="word-wrap:break-word">Hi Mark, Alex, Carolina
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<div>Attached is a pretty comprehensive book on using template classes and template functions in C++. Its a great way to fall asleep at night.</div>
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<div>There is a lot of things you can do with templates, but from my naive perspective its a great way to reduce the need for function overloading and only have a single copy of the function to maintain. The primary thing to remember is that the compiler will
write the actual code that gets implemented; therefore, the function templates are usually found in the header file (.h or .htp, or .hpp).</div>
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<div>One thing to be aware of is return types that differ from the types passed to the function arguments. For example:</div>
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<div>in the vonb.hpp file:</div>
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<div>template<typename t1, typename t2></div>
<div>t1 vonB(const t1 age, const t2 linf, const t2, vonbk)</div>
<div>{</div>
<div><span class="x_Apple-tab-span" style="white-space:pre"></span>return(linf*(1.-exp(-vonbk*age)));</div>
<div>}</div>
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<div>in your tpl file:</div>
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<div>dvector age(1,5);</div>
<div>age.fill_seqadd(1,1);</div>
<div>dvar_vector len(1,5);</div>
<div>len = vonB(age,linf,vbk);</div>
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<div>In this case, the function returns a dvector, but assigns it to a dvar_vector. And this will be problematic.</div>
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<div>Steve</div>
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<div>On Jun 27, 2014, at 11:05 A</div>
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<div>M, Mark Maunder <<a href="mailto:mmaunder@iattc.org">mmaunder@iattc.org</a>> wrote:</div>
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Hi developers,</div>
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I am in the process or putting together a model that will be used to evaluate several growth equations so I thought I better try to use the ADMB project “approved” approach for writing the functions. Below is a template function and documentation for the von
Bertalanffy growth equation. I would appreciate any advice on doing this “correctly”.</div>
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Thanks,</div>
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Mark</div>
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/**</div>
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\defgroup CONTRIB Contributed libraries</div>
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*/</div>
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/**</div>
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\ingroup CONTRIB</div>
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\defgroup CAPAM CAPAM created functions</div>
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*/</div>
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#include <admodel.h></div>
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/** von Bertalanffy growth equation; constant objects.</div>
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\ingroup CAPAM</div>
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\brief Calculate the length from a given age based on the von Bertalanffy equation. Written by Mark Maunder.</div>
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\param age age of individual, \f$a\f$.</div>
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\param Linf asymptotic length, \f$L_inf\f$.</div>
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\param K growth rate, \f$K\f$.</div>
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\param t0 age at zero length, \f$t_0\f$.</div>
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\return length predicted length of individual. \f$L_inf*(1-exp(-K*(a-t0)))\f$.</div>
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*/</div>
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template <typename type1, typename type1></div>
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//can have multiple types so that they are used below in variable definitions, they can differ between function calls, but remain the same within a function call</div>
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//type1 is probably a long</div>
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//type2 is probably a dvariable (either a model parameter (Linf K t0) or a derived variable (length))</div>
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//may need a type3, which is a dvar_vector if age and length are vectors, where type 1 will be a vector</div>
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type1 vonB(const type1 &age, const type2 &Linf, const type2 &K, const type2 &t0)</div>
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{</div>
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type2 length = Linf*(1.-mfexp(-K*(age-t0)));</div>
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return (length);</div>
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} </div>
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//is length a bad word to use</div>
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//do we use ingroup for both groups and subgroups in doxygen documentation</div>
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//should we use mfexp?</div>
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//what if age and length are vectors, but age is a vector and length is a dvar_vector, do we need to overload the type with one with three variable types</div>
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//I couldn't work out how to put in the detailed description</div>
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//The equations did not work on my computer</div>
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