c++ - Best practices for functions with multiple Eigen objects as parameters -

-

i find design of functions eigen objects parameters cumbersome. while information in eigen documentation helpful, suggests awkward approach template arguments. suppose, want write geometric routine line-plane-intersection. simple , transparent approach be:

template<typename _tp>  bool planelineintersect(const eigen::matrix<_tp, 3, 1>& planepoint,                          const eigen::matrix<_tp, 3, 1>& planenormal,                          const eigen::matrix<_tp, 3, 1>& linepoint,                          const eigen::matrix<_tp, 3, 1>& linedir,                         eigen::matrix<_tp, 3, 1>& intersectionpoint)

this looks relatively pleasing , looks @ can learn every parameter shall 3d vector of same type. however, directly, not allow eigen expressions of kind (we have call eigen::matrix constructors every expression, use). if expressions used this, need create unnecessary temporaries.

the suggested solution is:

template<typename derived1, typename derived2, typename derived3, typename derived4, typename derived5>  bool planelineintersect(const eigen::matrixbase<derived1>& planepoint,                          const eigen::matrixbase<derived2>& planenormal,                          const eigen::matrixbase<derived3>& linepoint,                          const eigen::matrixbase<derived4>& linedir,                         const eigen::matrixbase<derived5>& intersectionpoint)

this not reveal matrices expected, nor parameters used input , output, have const-cast intersectionpoint allow expressions in output parameters. understand it, way allow eigen expressions in function parameters. despite unelegant expression support, first snippet still seems more likable me.

my questions:

  1. would consider second code snippet best solution example?
  2. do ever use const-cast solution output parameters or think not worth loss in transparency?
  3. what guidelines/best practices use eigen function writing?

for such small fixed size objects, i'd not bother , go first solution.

it's approach have output function parameters. in particular case, 1 approach create planelineintersection class ctor take plane , line, stores result of intersection , provides accessors query result of computation (no intersection, point, line).

btw, have noticed hyperplane , parametrizedline class of eigen/geometry module? parametrizedline class has intersectionpoint member hyperplane (though it's limited because assumes intersection exist , point).


Comments

Post a Comment

Popular posts from this blog

java - activate/deactivate sonar maven plugin by profile? -

-
i use sonar plugin executes if activated in maven profile. sonar runs on every compile. the problem build fail other team members not have sonar application installed locally. pom.xml checked in team members same copy including sonar configuration, don't want them modify purpose of disabling sonar (they might inadvertently check modified copy in). please advise how configure maven (.m2/settings.xml) and/or pom.xml sonar feature can enabled/disabled local profile. here sonar configuration in each project's pom.xml: <plugin> <groupid>org.codehaus.mojo</groupid> <artifactid>sonar-maven-plugin</artifactid> <version>1.0</version> <executions> <execution> <id>make-sonar</id> <phase>compile</phase> <goals> <goal>sonar</goal> </goals> </execution> </executions> ...
Read more

python - TypeError: can only concatenate tuple (not "float") to tuple -

-
i'm new python, question might easy, anyway, patience: as trying call newton-raphson method calculate implied volatility in black-scholes formula call/put option pricing, first thing is, newton method in scipy.optimize seems calculate function's zeros, in black-scholes formula, want function's value option price, not zero. (i'm new here programming, i'm not sure techniques.) should write function things like: def f(sigma, price): return bsformula(s0,k,r,t,q,sigma) - price then, while calling newton method, takes args=() 1 parameter in function, write this: value = newton(bsprice2, 0.5, args=price) but error message: file "bs.py", line 36, in bsimpvol value = newton(bsprice2, 0.5, args=float(price)) file "/usr/lib/python2.7/dist-packages/scipy/optimize/zeros.py", line 143, in newton q0 = func(*((p0,) + args)) typeerror: can concatenate tuple (not "float") tuple could tell me why that? how fix it? apprecia...
Read more

java - What is the difference between String. and String.this. ? -

-
this question has answer here: meaning of .this , .class in java 2 answers i'll straight point. im still learning bit of syntax , want know difference between code is code a: public class buttonz extends jbutton{ public buttonz(){ settext(new string(string.valueof(i))); } } please ignore fact i undeclared, not lost. code b: public class buttonz extends jbutton{ public buttonz(){ settext(new string(string.this.charat(i))); } } what don't yet understand difference in typing string.this , string. i under assumption when use dot operator on class accessing it's static methods(and/or variables if they're not hidden). i have studied little bit , have concluded when using string. accessing string static methods.. when using string.this. i'm accessing methods class buttonz extendi...
Read more