feat: implement QUANTUM function (#89)

Fixes #87

Co-authored-by: Chris Campbell <[email protected]>

models/quantum/quantum.dat

@@ -0,0 +1,33 @@
+a
+0	1
+1	1
+b
+0	0
+1	0
+c
+0	0
+1	0
+d
+0	-1
+1	-1
+e
+0	110
+1	110
+f
+0	48
+1	48
+FINAL TIME
+0	1
+g
+0	378
+1	378
+h
+0	10
+1	10
+INITIAL TIME
+0	0
+SAVEPER
+0	1
+1	1
+TIME STEP
+0	1

models/quantum/quantum.mdl

@@ -0,0 +1,44 @@
+{UTF-8}
+a = QUANTUM(1.9, 1.0) ~~~:SUPPLEMENTARY|
+b = QUANTUM(0.9, 1.0) ~~~:SUPPLEMENTARY|
+c = QUANTUM(-0.9, 1.0) ~~~:SUPPLEMENTARY|
+d = QUANTUM(-1.9, 1.0) ~~~:SUPPLEMENTARY|
+e = QUANTUM(112.3, 10.0) ~~~:SUPPLEMENTARY|
+f = QUANTUM(50, 12) ~~~:SUPPLEMENTARY|
+g = QUANTUM(423, 63) ~~~:SUPPLEMENTARY|
+h = QUANTUM(10, 10) ~~~:SUPPLEMENTARY|
+
+********************************************************
+	.Control
+********************************************************~
+		Simulation Control Parameters
+	|
+
+INITIAL TIME = 0 ~~|
+FINAL TIME = 1 ~~|
+TIME STEP = 1 ~~|
+SAVEPER = TIME STEP ~~|
+
+\\\---/// Sketch information - do not modify anything except names
+V300  Do not put anything below this section - it will be ignored
+*View 1
+$0-0-0,0,|0||0-0-0|0-0-0|0-0-0|0-0-0|0-0-0|0,0,100,0
+///---\\\
+:L<%^E!@
+9:quantum
+15:0,0,0,0,0,0
+19:100,0
+27:2,
+34:0,
+5:FINAL TIME
+35:Date
+36:YYYY-MM-DD
+37:2000
+38:1
+39:1
+40:2
+41:0
+42:1
+24:0
+25:0
+26:0

models/quantum/quantum_vars.txt

@@ -0,0 +1,66 @@
+a: aux
+= QUANTUM(1.9,1.0)
+refId(_a)
+hasInitValue(false)
+
+b: aux
+= QUANTUM(0.9,1.0)
+refId(_b)
+hasInitValue(false)
+
+c: aux
+= QUANTUM(-0.9,1.0)
+refId(_c)
+hasInitValue(false)
+
+d: aux
+= QUANTUM(-1.9,1.0)
+refId(_d)
+hasInitValue(false)
+
+e: aux
+= QUANTUM(112.3,10.0)
+refId(_e)
+hasInitValue(false)
+
+f: aux
+= QUANTUM(50,12)
+refId(_f)
+hasInitValue(false)
+
+FINAL TIME: const
+= 1
+refId(_final_time)
+hasInitValue(false)
+
+g: aux
+= QUANTUM(423,63)
+refId(_g)
+hasInitValue(false)
+
+h: aux
+= QUANTUM(10,10)
+refId(_h)
+hasInitValue(false)
+
+INITIAL TIME: const
+= 0
+refId(_initial_time)
+hasInitValue(false)
+
+SAVEPER: aux
+= TIME STEP
+refId(_saveper)
+hasInitValue(false)
+refs(_time_step)
+
+Time: const
+= 
+refId(_time)
+hasInitValue(false)
+
+TIME STEP: const
+= 1
+refId(_time_step)
+hasInitValue(false)
+

src/c/vensim.h

@@ -26,6 +26,8 @@ extern "C" {
 #define _MAX(a, b) fmax(a, b)
 #define _MIN(a, b) fmin(a, b)
 #define _MODULO(a, b) fmod(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)
 #define _SQRT(x) sqrt(x)