Arbitrary precision argument

paulmasson · May 23, 2023 · bb4deb9 · bb4deb9
1 parent 6203607
commit bb4deb9
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Showing 3 changed files with 12 additions and 0 deletions.
diff --git a/build/math.js b/build/math.js
@@ -229,6 +229,8 @@ function abs( x ) {
 
 function arg( x ) {
 
+  if ( isArbitrary(x) ) return ln(x).im;
+
   // adding zero prevents unexpected behavior for -0
 
   if ( isComplex(x) ) return Math.atan2( x.im + 0, x.re + 0 );
@@ -3463,6 +3465,10 @@ function ln( x ) {
     if ( x === 0n || x.re === 0n && x.im === 0n )
       throw Error( 'Arbitrary natural logarithm singularity' );
 
+    if ( x.re === 0n )
+      if ( x.im > 0n ) return { re: ln(x.im), im: halfPi };
+      else return { re: ln(-x.im), im: -halfPi };
+
     // convergence near unit circle problematic
     // scale argument radially and subtract scaling
     // any number will work, convergence faster further out

diff --git a/src/functions/logarithm.js b/src/functions/logarithm.js
@@ -168,6 +168,10 @@ function ln( x ) {
     if ( x === 0n || x.re === 0n && x.im === 0n )
       throw Error( 'Arbitrary natural logarithm singularity' );
 
+    if ( x.re === 0n )
+      if ( x.im > 0n ) return { re: ln(x.im), im: halfPi };
+      else return { re: ln(-x.im), im: -halfPi };
+
     // convergence near unit circle problematic
     // scale argument radially and subtract scaling
     // any number will work, convergence faster further out

diff --git a/src/operators.js b/src/operators.js
@@ -192,6 +192,8 @@ function abs( x ) {
 
 function arg( x ) {
 
+  if ( isArbitrary(x) ) return ln(x).im;
+
   // adding zero prevents unexpected behavior for -0
 
   if ( isComplex(x) ) return Math.atan2( x.im + 0, x.re + 0 );