Crazy Math Conversion Question

[buntay]

Hello collective I'm back....hahaha

I have a question for the mathematicians among us. I need a multiplier of 3 but every 4th entry add 1.... hard to explain so here is the code. The only thing is the b1 numbers cant change from what I have listed in code.

setfreq m8

main:
count c.2,3000 ,b0
readtemp C.1, b2
readadc10 C.0,w2
b3=b2 *9 /5 + 32

if b0 < 4 then nevermind
if b0 = 4 then let b1= 13
if b0 = 5 then let b1= 16
if b0 = 6 then let b1= 20
if b0 = 7 then let b1= 23
if b0 = 8 then let b1= 26
if b0 = 9 then let b1= 30
if b0 = 10 then let b1= 33
if b0 = 11 then let b1= 36
if b0 = 12 then let b1= 40
if b0 = 13 then let b1= 43
if b0 = 14 then let b1= 46
if b0 = 15 then let b1= 50
if b0 = 16 then let b1= 53
if b0 = 17 then let b1= 56
if b0 = 18 then let b1= 60
if b0 = 19 then let b1= 63
if b0 = 20 then let b1= 66
if b0 = 21 then let b1= 70
if b0 = 22 then let b1= 73
if b0 = 23 then let b1= 76
if b0 = 24 then let b1= 80
if b0 = 25 then let b1= 83
if b0 = 26 then let b1= 86
if b0 = 27 then let b1= 90
if b0 = 28 then let b1= 93
if b0 = 29 then let b1= 96
if b0 = 30 then let b1= 100
if b0 = 31 then let b1= 103
if b0 = 32 then let b1= 106
if b0 = 33 then let b1= 110
if b0 = 34 then let b1= 113
if b0 = 35 then let b1= 116
if b0 = 36 then let b1= 120
if b0 = 37 then let b1= 123
if b0 = 38 then let b1= 126
if b0 = 39 then let b1= 130
if b0 = 40 then let b1= 133
if b0 = 41 then let b1= 136
if b0 = 42 then let b1= 140
if b0 = 43 then let b1= 143
if b0 = 44 then let b1= 146
if b0 = 45 then let b1= 150
if b0 = 46 then let b1= 153
if b0 = 47 then let b1= 156
if b0 = 48 then let b1= 160
if b0 = 49 then let b1= 163
if b0 = 50 then let b1= 166
if b0 = 51 then let b1= 170
if b0 = 52 then let b1= 173
if b0 = 53 then let b1= 176
if b0 = 54 then let b1= 180
if b0 = 55 then let b1= 183
if b0 = 56 then let b1= 186
if b0 = 57 then let b1= 190
if b0 = 58 then let b1= 193
if b0 = 59 then let b1= 196
if b0 = 60 then let b1= 200
if b0 = 61 then let b1= 203
if b0 = 62 then let b1= 206
if b0 = 63 then let b1= 210
if b0 = 64 then let b1= 213
if b0 = 65 then let b1= 216
if b0 = 66 then let b1= 220
if b0 = 67 then let b1= 223
if b0 = 68 then let b1= 226
if b0 = 69 then let b1= 230
if b0 = 70 then let b1= 233
if b0 = 71 then let b1= 236
if b0 = 72 then let b1= 240
if b0 = 73 then let b1= 243
if b0 = 74 then let b1= 246
if b0 = 75 then let b1= 250
if b0 = 76 then let b1= 253
if b0 = 77 then let b1= 256
if b0 = 78 then let b1= 260
if b0 = 79 then let b1= 263
if b0 = 80 then let b1= 266
if b0 = 81 then let b1= 270
if b0 = 82 then let b1= 273
if b0 = 83 then let b1= 276
if b0 = 84 then let b1= 280
if b0 = 85 then let b1= 283
if b0 = 86 then let b1= 286
if b0 = 87 then let b1= 290
if b0 = 88 then let b1= 293
if b0 = 89 then let b1= 296
if b0 = 90 then let b1= 300
if b0 = 91 then let b1= 303
if b0 = 92 then let b1= 306
if b0 = 93 then let b1= 310
if b0 = 94 then let b1= 313
if b0 = 95 then let b1= 316
if b0 = 96 then let b1= 320
if b0 = 97 then let b1= 323
if b0 = 98 then let b1= 326
if b0 = 99 then let b1= 330
if b0 = 100 then let b1=333


sertxd (#b1,",",#b3,",",#w2,cr,lf)

nevermind:
goto main

Any help would be much appreciated.

Side note: I did not use a word variable for count, because count will NEVER be higher than 100

 

[hippy]

Can't guarantee this is right but something like this ...

b1 = (b0*3) + ( (b0 mod 4) Max 1 )

Or in PICAXE Basic ...

b1 = b0 Mod 4 Max 1
b1 = b0 * 3 + b1

But note you can't store anything greater than 255 in byte variables; eg b1 = 333

 

[hippy]

I need a multiplier of 3 but every 4th entry add 1

Not quite according to your code. Take b0 multiply by 3, then look to see how many you need to add to get the b1 result ...

1 * 3 + 0 = 3
2 * 3 + 0 = 6
3 * 3 + 0 = 9
4 * 3 + 1 = 13
5 * 3 + 1 = 16
6 * 3 + 2 = 20
7 * 3 + 2 = 23
8 * 3 + 2 = 26
9 * 3 + 3 = 30
10 * 3 + 3 = 33
11 * 3 + 3 = 36

There are only two "+ 1" entries in there so something is amiss.

 

[marks]

Hi buntay,
try this maybe

setfreq m8

main:
count c.2,3000 ,w0
readtemp C.1, b2
readadc10 C.0,w2
b3=b2 *9 /5 +32

if w0 < 4 then main
w0=w0 *10 /3


sertxd (#w0,",",#b3,",",#w2,cr,lf)

 

[Goeytex]

Side note: I did not use a word variable for count, because count will NEVER be higher than 100

However, b1 WILL be greater than 100 and needs to be a WORD variable.

Here's a simple solution that does not require funny maths.

EEPROM 0,  (0,0,0,0,1,1,2,2,2,3,3,3,4,4,4,5,5,5,6,6,6,7,7,7,8,8,8,9,9,9)
EEPROM 30, (10,10,10,11,11,11,12,12,12,13,13,13,14,14,14,15,15,15,16,16,16,17,17,17,18,18,18,19,19,19)
EEPROM 60, (20,20,20,21,21,21,22,22,22,23,23,23,24,24,24,25,25,25,26,26,26,27,27,27,28,28,28,29,29,29)
EEPROM 90, (30,30,30,31,31,31,32,32,32,33,33)

setfreq m8

Symbol addend = b10

main:
  count c.2,3000 ,b0
  readtemp C.1, b2
  readadc10 C.0,w2
  b3 = b2 * 9 / 5 + 32

Read b0, addend
w3 = b0 * 3 + addend 

sertxd (#w3,",",#b3,",",#w2,cr,lf)

goto main

 

[westaust55]

Taking into account the "anomoly" mentioned by hippy, this will otherwise work

w1 = b0 /3 : w1 = b0*3 + b1 ; using w1 (not b1) to allow for results > 255

 

[buntay]

Actually, Marks formula works perfectly.

Thanks all

 

[Axel87]

Just wanted to chime in on this one.
Can anyone expand on Marks formula, as far as what the code is doing?
For us not-so-brilliant guys out there?

 

[BeanieBots]

*9 /5 +32 looks very much like Celcius to Farenheight conversion.
(the +1's probably being to take into account rounding errors)

 

[westaust55]

Just wanted to chime in on this one.
Can anyone expand on Marks formula, as far as what the code is doing?
For us not-so-brilliant guys out there?

If you think about the solution that I provided,
First I calculated one-third of b0 and then added that to b0 * 3 to get the final answer is in effect multiplying by 3 and 1/3

Marks more elegant solution uses b0 * 10 / 3
10 / 3 = 3 and 1/3

Both rely upon the integer math giving only the whole number for each group of three.