How can I generate random numbers for the demo charts that roughly match the top and right?
I need to generate random numbers for several charts that go up and to the right.
I'm using JavaScript's charting engine, so numbers will eventually be needed in JSON, but I can handle the conversion if you have an easy way outside of JavaScript.
Here's a simple random number generator in JavaScript:
function randomNumber(minimum, maximum){
return Math.round( Math.random() * (maximum - minimum) + minimum);
}
console.log(randomNumber(0,100));
The above would work if min
u max
grew over time. Can you point me in the right direction?
Here's a JSFiddle to try various solutions, including a handy graph: http://jsfiddle.net/9ox4wjrf/
Here's an example that I have to build using the generated data:
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Something like this might work:
var a = 0.05;
var b = 10; //play with these values to your liking
var y;
//loop here from 0 to whatever
y = a * x^2 + b * x * Math.random();
//or using your randomMumber function:
y = a * x^2 + randomMumber(- b * x / 2, b * x / 2);
Thus, the noise becomes greater as you go further to the right.
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Define your trend silently, like an array of growing numbers. Call this X and copy it to another Y array. Then, for each Y point, add the number generated by Math's built-in random number generator. This will add the illusion of noise.
If you want more random options, check out random-js on GitHub. https://github.com/mobiusklein/random-js . It's a great library, but forks help smooth out rough edges. Also, https://github.com/tmcw/simple-statistics for linear regression lines.
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It will be pseudocode, but you can do something like this:
int randomRangePotential = 20; // percentage of random growth/shrinkage
int likelyhoodOfGrowth = 95; // likelyhood of datapoint being more than the previous
int numberOfDataPoints = 100; // number of data points to generate
int lastDataPointValue = 50;
for (int iterator = 0; iterator < numberOfDataPoints; iterator++)
{
// generate random number to determine positive or negative growth 0 - 100
// generate randomRange, a random number between 1 and randomRangePotential
// if random number > likelyhoodOfGrowth
// generate random number for datapoint that is (lastDataPoint = lastDataPoint * 1.randomRange)
// add the random number to a datapoint
// if random number < likelyhoodOfGrowth
// generate random number for datapoint that is (lastDataPoint = lastDataPoint * -1.randomRange)
// add the random number to a datapoint
// lastDataPointValue = thisdatapoint
}
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