I am building a line graph from an array that is built from a db of user entered data.
What I need help with is adding any missing values. (Linear Interpolation)
Figuring out the value if there is only 1 value missing is simple (start value+end value/2), but if there is more than 1 value missing in a row it becomes more difficult.
1 missing value example:
$sample=array(1.3,2.1,,4.7);
how to figure it out: the missing value is this case is (2.1+4.7)/2 = 3.4
2 missing value example:
$sample=array(2.4,3.1,,,6.9);
how to figure it out: ??
I need a php function that accepts 3 vars and returns the calculated values for each of the missing values. (I guess it makes sense to return the calculated values in an array)
function buildMissingValues($startValue,$endValue,$numberOfMissingValues){
//brilliant code here
}
In the above "2 missing value" example I would like to:
$newValues=buildMissingValues(3.1,6.9,2);
and have an array returned with 2 values that complete the line chart points.
I'm not sure if I have explained this well enough.
I REALLY appreciate your help!!
Function for line chart: Linear Interpolation Missing values
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HappyJupiter
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shawngoldw
- Forum Contributor
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Re: Function for line chart: Linear Interpolation Missing va
This sounds like more of a math problem. I didn't write up the function but this logic should work:
stepSize = (end - start) / (numMissing + 1)
Then you can loop:
previous = start
for 0 to numMissing
ret[] = previous + stepSize
Lemme know how this works out.
Shawn
stepSize = (end - start) / (numMissing + 1)
Then you can loop:
previous = start
for 0 to numMissing
ret[] = previous + stepSize
Lemme know how this works out.
Shawn
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HappyJupiter
- Forum Newbie
- Posts: 6
- Joined: Sat Aug 14, 2010 10:36 am
Re: Function for line chart: Linear Interpolation Missing va
Thanks Shawn - you gave me a few great tidbits that help me get over the hump.
Got it all figured out and implemented and it works fabulously
Thanks again!
Got it all figured out and implemented and it works fabulously
Thanks again!
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shawngoldw
- Forum Contributor
- Posts: 212
- Joined: Mon Apr 05, 2010 3:38 pm
Re: Function for line chart: Linear Interpolation Missing va
No problem!
glad to help
glad to help