r - Obtain inverse function analytically instead of numerically -


i implemented 

> inverse = function (f, lower = -100, upper = 100) {    function (y) uniroot((function (x) f(x) - y), lower = lower, upper = upper)[1] }  > square_inverse = inverse(function (x) x^2, 0.1, 100)  > square_inverse(4) [1] 1.999976

from solving inverse of function in r , happy worked :) despite visible in origin solution unfortunately not analytic one. there way exact solution or @ least improve approximation of above code?


Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj...
Read more

Qt QGraphicsScene is not accessable from QGraphicsView (on Qt 5.6.1) -

i new qt. trying catch mouse press , release in qgraphicsview area , draw line. this, extended qgraphicsview , called myqgraphicsview . seems scene not attached since added " hello world " , never appears in view. here code extended class: class myqgraphicsview : public qgraphicsview { q_object public: myqgraphicsview(qgraphicsscene *scene, qwidget *parent = q_nullptr) : qgraphicsview(scene,parent){ // qgraphicsview::qgraphicsview(scene,parent); } qpoint *pointptr, *startpos,*endpos; qgraphicsview *cv;//maa qgraphicsscene *c; qgraphicsscene *sceneptr; // maa protected: void paintevent(qpaintevent *event) { show(); } void mousepressevent(qmouseevent *event) { // pos wrt widget. global wer global screen qdebug()<<" mouse pressed @ "<<qwidget::mapfromglobal(event->globalpos()); //globalx(); startpos = new qpoint; startpos->setx(qwidget::mapfromglobal(event->globalpos()).x()); startpos->sety(qw...
Read more

What is happening when Matlab is starting a "parallel pool"? -

running parallel cpu processes in matlab starts command parpool() according documentation , function: [creates] special job on pool of workers, , [connects] matlab client parallel pool. this function takes bit of time execute, on order of 30 seconds. in other multi-cpu paradigms openmp, parallel execution seems totally transparent -- i've never noticed behavior analogous matlab (granted i'm not experienced parallel programming). so, happening between time parpool() called , when finishes executing? takes long? parallel computing toolbox enables run matlab code in parallel using several different paradigms (e.g. jobs , tasks, parfor , spmd , parfeval , batch processing), , run either locally (parallelised across cores in local machine) or remotely (parallelised across machines in cluster - either 1 own, or 1 in cloud). in of these cases, code run on matlab workers , copies of matlab without interactive desktop. if you're intending run on remo...
Read more