From: oetiker <oetiker@a5681a0c-68f1-0310-ab6d-d61299d08faa>
Date: Tue, 4 May 2004 21:01:29 +0000 (+0000)
Subject: Added the ATAN function. This is being used to convert a DS for each vector component... 
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=2412c8211fbd8e6cb077a0785ab335416a7090fa;p=rrdtool.git

Added the ATAN function. This is being used to convert a DS for each vector component of wind direction into a
single direction for graphing. CDEF:avdir=yavg,xavg,/,ATAN,57.296,*,xavg,0,LT,180,0,IF,+,DUP,0,LT,360,0,IF,+
-- Daniel Shiels <dan@marge.tofubar.com>


git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@247 a5681a0c-68f1-0310-ab6d-d61299d08faa
---

diff --git a/doc/rrdgraph_rpn.src b/doc/rrdgraph_rpn.src
index f9ac7fe..65f0917 100644
--- a/doc/rrdgraph_rpn.src
+++ b/doc/rrdgraph_rpn.src
@@ -98,6 +98,10 @@ B<SIN, COS, LOG, EXP>
 
 Sine, cosine (input in radians), log, exp (natural logarithm)
 
+B<ATAN>
+
+Arctangent. Output in radians.
+
 B<FLOOR, CEIL>
 
 Round down,up to the nearest integer
diff --git a/src/rrd_rpncalc.c b/src/rrd_rpncalc.c
index 65748cc..52d7a11 100644
--- a/src/rrd_rpncalc.c
+++ b/src/rrd_rpncalc.c
@@ -153,6 +153,7 @@ void rpn_compact2str(rpn_cdefds_t *rpnc,ds_def_t *ds_def,char **str)
 	  add_op(OP_NOW,NOW)
 	  add_op(OP_LTIME,LTIME)
 	  add_op(OP_TIME,TIME)
+	  add_op(OP_ATAN,ATAN)
 
 #undef add_op
               }
@@ -321,6 +322,7 @@ rpn_parse(void *key_hash,char *expr,long (*lookup)(void *,char*)){
 	match_op(OP_NOW,NOW)
 	match_op(OP_LTIME,LTIME)
 	match_op(OP_TIME,TIME)
+	match_op(OP_ATAN,ATAN)
 
 #undef match_op
 
@@ -501,6 +503,10 @@ rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
 		stackunderflow(0);
 		rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
 		break;
+	    case OP_ATAN:
+		stackunderflow(0);
+		rpnstack -> s[stptr] = atan(rpnstack -> s[stptr]);
+		break;
 	    case OP_COS:
 		stackunderflow(0);
 		rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
diff --git a/src/rrd_rpncalc.h b/src/rrd_rpncalc.h
index 2aa6dfb..fe456f2 100644
--- a/src/rrd_rpncalc.h
+++ b/src/rrd_rpncalc.h
@@ -6,7 +6,7 @@
 #ifndef _RRD_RPNCALC_H
 #define _RRD_RPNCALC_H
 
-/* WARNING: if new operators are added, they MUST be added after OP_END.
+/* WARNING: if new operators are added, they MUST be added at the very end of the list.
  * This is because COMPUTE (CDEF) DS store OP nodes by number (name is not
  * an option due to limited par array size). OP nodes must have the same
  * numeric values, otherwise the stored numbers will mean something different. */
@@ -15,7 +15,7 @@ enum op_en {OP_NUMBER=0,OP_VARIABLE,OP_INF,OP_PREV,OP_NEGINF,
 	    OP_DIV,OP_SIN, OP_DUP, OP_EXC, OP_POP,
 	    OP_COS,OP_LOG,OP_EXP,OP_LT,OP_LE,OP_GT,OP_GE,OP_EQ,OP_IF,
 	    OP_MIN,OP_MAX,OP_LIMIT, OP_FLOOR, OP_CEIL,
-	    OP_UN,OP_END,OP_LTIME,OP_NE,OP_ISINF,OP_PREV_OTHER,OP_COUNT};
+	    OP_UN,OP_END,OP_LTIME,OP_NE,OP_ISINF,OP_PREV_OTHER,OP_COUNT,OP_ATAN};
 
 typedef struct rpnp_t {
     enum op_en   op;