Merge branch 'bugfix/fix-the-phi0-definition' into 'main'

Fix the phi0 definition by using Math.atan2 instead of Math.atan

See merge request belle2/software/display!2

Author: GiacomoXT

docs/source/developer/installation.rst

@@ -5,10 +5,15 @@ Installation
 
 For developers, to set up the local environment, please follow the steps below.
 
-1. **Install Node.js** on your system. You can download the latest version of Node.js from the `official website`_.
+1. **Install Node.js** on your system. You can download the latest version of Node.js from the
+   `official website`_.
+
+   Note that the recommended version of Angular CLI (see below) requires a minimum Node.js version
+   of v14.20, v16.30, v18.10 or v20.0.
 
 .. _official website: https://nodejs.org/en/download
 
+
 2. **Install Angular CLI** globally by running the following command:
 
    .. code-block:: console
@@ -27,7 +32,7 @@ For developers, to set up the local environment, please follow the steps below.
 
       $ cd display
 
-5. Run ``npm install`` to install the necessary dependencies
+5. Run ``npm install`` to install the necessary dependencies.
 
 6. Run ``npm start`` or ``ng serve`` to start the development server.
 

src/app/event-display/event-loader.ts

@@ -98,7 +98,7 @@ class TEventSelector extends TSelector {
                 let points: [number, number, number][] = [];
                 const rho = Math.sqrt(px * px + py * py) / 0.0045; // approximation and only for charge != 0
                 const tanLambda = pz / Math.sqrt(px * px + py * py);
-                const phi0 = Math.atan(py / px);
+                const phi0 = Math.atan2(py, px);
 
                 if (charge === 0) {
                     if (

src/loaders/event-data-loader.ts

@@ -260,8 +260,8 @@ export class Belle2Loader extends PhoenixLoader {
                     ...(particle?.trackIndex > -1 && {
                         Track: particle.trackIndex
                     }),
-                    phi: Math.atan(
-                        particle?.momentum_x / particle?.momentum_y
+                    phi: Math.atan2(
+                        particle?.momentum_x, particle?.momentum_y
                     ).toPrecision(5),
                     PDG: particle.PDG,
                     color: this.getParticleColor(particle.PDG),

src/loaders/objects/klmCluster.ts

@@ -1,7 +1,7 @@
 import * as THREE from 'three';
 
 const getPhi = (vector: THREE.Vector3) => {
-    return Math.atan(vector.y / vector.x);
+    return Math.atan2(vector.y, vector.x);
 };
 
 const getR = (vector: THREE.Vector3) => {
@@ -11,8 +11,8 @@ const getR = (vector: THREE.Vector3) => {
 };
 
 const getTheta = (vector: THREE.Vector3) => {
-    return Math.atan(
-        Math.sqrt(vector.x * vector.x + vector.y * vector.y) / vector.z
+    return Math.atan2(
+        Math.sqrt(vector.x * vector.x + vector.y * vector.y), vector.z
     );
 };