Formula 1

Display interpreted functions.

Author: Rene Brun
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Sunday, September 19, 2021 at 07:39 AM.

In [1]:
TCanvas *c1 = new TCanvas("c1","Example with Formula",200,10,700,500);

We create a formula object and compute the value of this formula for two different values of the x variable.

In [2]:
auto form1 = new TFormula("form1","sqrt(abs(x))");
form1->Eval(2);
form1->Eval(-45);

Create a one dimensional function and draw it

In [3]:
auto fun1 = new TF1("fun1","abs(sin(x)/x)",0,10);
c1->SetGridx();
c1->SetGridy();
fun1->Draw();
c1->Update();

Before leaving this demo, we print the list of objects known to ROOT

In [4]:
if (gObjectTable) gObjectTable->Print();
Object statistics
class                         cnt    on heap     size    total size    heap size
================================================================================
TList                         131        131      104         13624        13624
TObjectTable                    1          1       32            32           32
TROOT                           1          0      728           728            0
TPluginManager                  1          1       40            40           40
THashTable                      1          1       72            72           72
THashList                       1          1      112           112          112
TEnv                            1          1       56            56           56
TEnvRec                       144        144       96         13824        13824
TUnixSystem                     1          1      672           672          672
TOrdCollection                  4          4       72           288          288
--------------------------------------------------------------------------------
Total:                        286        285     1984         29448        28720
================================================================================

Draw all canvases

In [5]:
%jsroot on
gROOT->GetListOfCanvases()->Draw()