From 8fc1ee8e587c4224862f0dec0772627dc6f6acfa Mon Sep 17 00:00:00 2001
From: Todd Fincannon <66087780+ToddFincannonEI@users.noreply.github.com>
Date: Thu, 8 Dec 2022 13:09:06 -0800
Subject: [PATCH] feat: add the Vensim POWER functions as a C macro (#286)

Fixes #283
---
 models/power/power.dat      | 20 ++++++++++++++++++++
 models/power/power.mdl      | 10 ++++++++++
 packages/cli/src/c/vensim.h |  1 +
 3 files changed, 31 insertions(+)
 create mode 100644 models/power/power.dat
 create mode 100644 models/power/power.mdl

diff --git a/models/power/power.dat b/models/power/power.dat
new file mode 100644
index 00000000..0ac76f23
--- /dev/null
+++ b/models/power/power.dat
@@ -0,0 +1,20 @@
+a
+0	4
+1	4
+b
+0	1.41421
+1	1.41421
+base
+0	2
+c
+0	2.82843
+1	2.82843
+FINAL TIME
+0	1
+INITIAL TIME
+0	0
+SAVEPER
+0	1
+1	1
+TIME STEP
+0	1
diff --git a/models/power/power.mdl b/models/power/power.mdl
new file mode 100644
index 00000000..bbabae27
--- /dev/null
+++ b/models/power/power.mdl
@@ -0,0 +1,10 @@
+{UTF-8}
+base = 2 ~~|
+a = POWER(base, 2) ~~|
+b = POWER(base, 0.5) ~~|
+c = POWER(base, 1.5) ~~|
+
+INITIAL TIME = 0 ~~|
+FINAL TIME = 1 ~~|
+TIME STEP = 1 ~~|
+SAVEPER = TIME STEP ~~|
diff --git a/packages/cli/src/c/vensim.h b/packages/cli/src/c/vensim.h
index b5fb37b4..ca38e743 100644
--- a/packages/cli/src/c/vensim.h
+++ b/packages/cli/src/c/vensim.h
@@ -26,6 +26,7 @@ extern "C" {
 #define _MAX(a, b) fmax(a, b)
 #define _MIN(a, b) fmin(a, b)
 #define _MODULO(a, b) fmod(a, b)
+#define _POWER(a, b) pow(a, b)
 #define _QUANTUM(a, b) ((b) <= 0 ? (a) : (b) * trunc((a) / (b)))
 #define _SAMPLE_IF_TRUE(current, condition, input) (bool_cond(condition) ? (input) : (current))
 #define _SIN(x) sin(x)