fix(ootk-sgp4): moved constants to local scope for speed increase des…

…pite memory usage
thkruz · Jan 16, 2021 · 11b8c72 · 11b8c72
1 parent 959e37d
commit 11b8c72
Showing 1 changed file with 48 additions and 77 deletions.
diff --git a/src/ootk-sgp4.ts b/src/ootk-sgp4.ts
@@ -90,39 +90,6 @@
 const PI = Math.PI;
 const TAU = PI * 2;
 const DEG2RAD = PI / 180.0;
-const x2o3 = 2.0 / 3.0;
-const xpdotp = 1440.0 / (2.0 * PI); // 229.1831180523293;
-const zes = 0.01675;
-const zel = 0.0549;
-const c1ss = 2.9864797e-6;
-const c1l = 4.7968065e-7;
-const zsinis = 0.39785416;
-const zcosis = 0.91744867;
-const zcosgs = 0.1945905;
-const zsings = -0.98088458;
-const q22 = 1.7891679e-6;
-const q31 = 2.1460748e-6;
-const q33 = 2.2123015e-7;
-const root22 = 1.7891679e-6;
-const root44 = 7.3636953e-9;
-const root54 = 2.1765803e-9;
-const rptim = 4.37526908801129966e-3; // equates to 7.29211514668855e-5 rad/sec
-const root32 = 3.7393792e-7;
-const root52 = 1.1428639e-7;
-const znl = 1.5835218e-4;
-const zns = 1.19459e-5;
-const temp4 = 1.5e-12;
-const fasx2 = 0.13130908;
-const fasx4 = 2.8843198;
-const fasx6 = 0.37448087;
-const g22 = 5.7686396;
-const g32 = 0.95240898;
-const g44 = 1.8014998;
-const g52 = 1.050833;
-const g54 = 4.4108898;
-const stepp = 720.0;
-const stepn = -720.0;
-const step2 = 259200.0;
 
 /** @interface SatelliteRecord contains all of the orbital parameters necessary for running SGP4. It is generated by Sgp4.createSatrec.*/
 interface SatelliteRecord {
@@ -385,10 +352,10 @@ class Sgp4 {
 
     //  ---------------------- constants -----------------------------
     /** Ootk -- Declared outside the class at the top */
-    // zns = 1.19459e-5;
-    // zes = 0.01675;
-    // znl = 1.5835218e-4;
-    // zel = 0.0549;
+    const zns = 1.19459e-5;
+    const zes = 0.01675;
+    const znl = 1.5835218e-4;
+    const zel = 0.0549;
 
     //  --------------- calculate time varying periodics -----------
     let zm = zmos + zns * t;
@@ -662,15 +629,15 @@ class Sgp4 {
 
     // -------------------------- constants -------------------------
     /** Ootk -- These are declared outside the class at the top of the file */
-    // zes = 0.01675;
-    // zel = 0.0549;
-    // c1ss = 2.9864797e-6;
-    // c1l = 4.7968065e-7;
-    // zsinis = 0.39785416;
-    // zcosis = 0.91744867;
-    // zcosgs = 0.1945905;
-    // zsings = -0.98088458;
-    // TAU = 2.0 * Math.PI;
+    const zes = 0.01675;
+    const zel = 0.0549;
+    const c1ss = 2.9864797e-6;
+    const c1l = 4.7968065e-7;
+    const zsinis = 0.39785416;
+    const zcosis = 0.91744867;
+    const zcosgs = 0.1945905;
+    const zsings = -0.98088458;
+    const TAU = 2.0 * Math.PI;            
 
     //  --------------------- local variables ------------------------
     let s1,
@@ -1222,18 +1189,18 @@ class Sgp4 {
     /* --------------------- local variables ------------------------ */
     /** Ootk -- these are declared at the top instead */
 
-    // q22 = 1.7891679e-6;
-    // q31 = 2.1460748e-6;
-    // q33 = 2.2123015e-7;
-    // root22 = 1.7891679e-6;
-    // root44 = 7.3636953e-9;
-    // root54 = 2.1765803e-9;
-    // rptim = 4.37526908801129966e-3; // equates to 7.29211514668855e-5 rad/sec
-    // root32 = 3.7393792e-7;
-    // root52 = 1.1428639e-7;
-    // x2o3 = 2.0 / 3.0;
-    // znl = 1.5835218e-4;
-    // zns = 1.19459e-5;
+    const q22 = 1.7891679e-6;
+    const q31 = 2.1460748e-6;
+    const q33 = 2.2123015e-7;
+    const root22 = 1.7891679e-6;
+    const root44 = 7.3636953e-9;
+    const root54 = 2.1765803e-9;
+    const rptim = 4.37526908801129966e-3; // equates to 7.29211514668855e-5 rad/sec
+    const root32 = 3.7393792e-7;
+    const root52 = 1.1428639e-7;
+    const x2o3 = 2.0 / 3.0;
+    const znl = 1.5835218e-4;
+    const zns = 1.19459e-5;
 
     // sgp4fix identify constants and allow alternate values
     // just xke is used here so pass it in rather than have multiple calls
@@ -1604,18 +1571,18 @@ class Sgp4 {
     let { atime, em, argpm, inclm, xli, mm, xni, nodem, nm } = options;
 
     /** Ootk -- Declared at the top of the file instead */
-    // fasx2 = 0.13130908;
-    // fasx4 = 2.8843198;
-    // fasx6 = 0.37448087;
-    // g22 = 5.7686396;
-    // g32 = 0.95240898;
-    // g44 = 1.8014998;
-    // g52 = 1.050833;
-    // g54 = 4.4108898;
-    // rptim = 4.37526908801129966e-3; // equates to 7.29211514668855e-5 rad/sec
-    // stepp = 720.0;
-    // stepn = -720.0;
-    // step2 = 259200.0;
+    const fasx2 = 0.13130908;
+    const fasx4 = 2.8843198;
+    const fasx6 = 0.37448087;
+    const g22 = 5.7686396;
+    const g32 = 0.95240898;
+    const g44 = 1.8014998;
+    const g52 = 1.050833;
+    const g54 = 4.4108898;
+    const rptim = 4.37526908801129966e-3; // equates to 7.29211514668855e-5 rad/sec
+    const stepp = 720.0;
+    const stepn = -720.0;
+    const step2 = 259200.0;
 
     //  ----------- calculate deep space resonance effects -----------
     let dndt = 0.0;
@@ -1835,7 +1802,9 @@ class Sgp4 {
     let no = options.no;
 
     /* --------------------- local variables ------------------------ */
-    /** Ootk -- Declared at the top of the file */
+    const PI = Math.PI;
+    const TAU = PI * 2;    
+    const x2o3 = 2.0 / 3.0;
 
     // sgp4fix use old way of finding gst
     /** Ootk -- Declared at the top of the file */
@@ -2032,13 +2001,15 @@ class Sgp4 {
     } = options;
 
     /* --------------------- local variables ------------------------ */
-    /** Ootk -- Declared at the top of the file */
+    const PI = Math.PI;
+    const TAU = PI * 2;    
+    const x2o3 = 2.0 / 3.0;
 
     /* ------------------------ initialization --------------------- */
     // sgp4fix divisor for divide by zero check on inclination
     // the old check used 1.0 + Math.cos(PI-1.0e-9), but then compared it to
     // 1.5 e-12, so the threshold was changed to 1.5e-12 for consistency
-    // temp4 = 1.5e-12;
+    const temp4 = 1.5e-12;
 
     // ----------- set all near earth variables to zero ------------
     satrec.isimp = 0;
@@ -2684,8 +2655,8 @@ class Sgp4 {
     // the old check used 1.0 + cos(PI-1.0e-9), but then compared it to
     // 1.5 e-12, so the threshold was changed to 1.5e-12 for consistency
 
-    /** Ootk -- Declared at the top of the page */
-    // temp4 = 1.5e-12;
+    const x2o3 = 2.0 / 3.0;
+    const temp4 = 1.5e-12;
 
     // sgp4fix identify constants and allow alternate values
     // getgravconst( whichconst, tumin, mu, radiusearthkm, xke, j2, j3, j4, j3oj2 );
@@ -3125,8 +3096,7 @@ class Sgp4 {
     tleLine2: string,
     whichconst = 'wgs72',
     opsmode = 'i',
-  ): SatelliteRecord {
-    // xpdotp = 1440.0 / (2.0 * PI); // 229.1831180523293;
+  ): SatelliteRecord {    
     let year = 0;
 
     let satrec = {
@@ -3251,6 +3221,7 @@ class Sgp4 {
 
     // sgp4fix no longer needed
     // getgravconst( whichconst, tumin, mu, radiusearthkm, xke, j2, j3, j4, j3oj2 );
+    const xpdotp = 1440.0 / (2.0 * PI); // 229.1831180523293;
 
     satrec.error = 0;