# HG changeset patch
# User Chris Cannam
# Date 1406485281 -3600
# Node ID 14e3e3d5f9069fe4ce52d1c93a7eda520c093525
# Parent  1f5dd6fc196fc4d4d55ae750eb93faeb2b939b78
A couple of new complex functions

diff -r 1f5dd6fc196f -r 14e3e3d5f906 src/may/complex.yeti
--- a/src/may/complex.yeti	Tue Jun 24 15:32:06 2014 +0100
+++ b/src/may/complex.yeti	Sun Jul 27 19:21:21 2014 +0100
@@ -72,12 +72,18 @@
 angle c is ~Cplx -> number =
     c#getAngle();
 
+fromPolar mag angle is number -> number -> ~Cplx =
+    complex (mag * Math#cos(angle)) (mag * Math#sin(angle));
+
 sum' cc is list?<~Cplx> -> ~Cplx =
     complex (sum (map real cc)) (sum (map imaginary cc));
 
 add c1 c2 is ~Cplx -> ~Cplx -> ~Cplx =
     complex (real c1 + real c2) (imaginary c1 + imaginary c2);
 
+subtract c1 c2 is ~Cplx -> ~Cplx -> ~Cplx =
+    complex (real c1 - real c2) (imaginary c1 - imaginary c2);
+
 multiply c1 c2 is ~Cplx -> ~Cplx -> ~Cplx =
    (a = real c1;
     b = imaginary c1;
@@ -118,8 +124,10 @@
    complex,
    magnitude,
    angle,
+   fromPolar,
    sum = sum',
    add,
+   subtract,
    multiply,
    scale,
    zero,
@@ -136,8 +144,10 @@
    complex is number -> number -> complex_t,
    magnitude is complex_t -> number,
    angle is complex_t -> number,
+   fromPolar is number -> number -> complex_t,
    sum is list?<complex_t> -> complex_t,
    add is complex_t -> complex_t -> complex_t,
+   subtract is complex_t -> complex_t -> complex_t,
    multiply is complex_t -> complex_t -> complex_t,
    scale is number -> complex_t -> complex_t,
    zero is complex_t,