Um algoritmo para gerar dados gráficos falsos, mas realistas (que também apresentam tendências)

O realce de sintaxe aqui é uma droga, então você pode querer ler o código aqui: http://pastie.org/8494639

Você pode colocar o código em um terminal ruby ​​e ele irá gerar uma string que você pode copiar / colar no playground de gráficos do Google aqui: https://code.google.com/apis/ajax/playground/?type=visualization#line_chart

# In order to generate a semi-realistic looking graph behavior
# we use a sine function to generate periodic behavior(ups and downs). In order to avoid
# a graph that is too regular, we introduce randomness at two levels:
# The delta between steps across the x-axis is random, but within a range(deltavariance)
# The wavelength of the sine function is varied by randomly incrementing the index we pass
# to the sine function(sine_index)

# CONFIGURATION VARIABLES
yvalue
= 1 # start value
range
= 100 # y-range
deltavariance
= 10 # allowable variance between changes
sine_index
, wavelength = 0, 0.33 #index into our sine function that determines whether we change direction or not
i
, maxi = 0, 100 # our counter and its maximum
data
= {sine_index => yvalue} # seed our data structure with its first value
trend
= :positive # :negative, :none # do we want the graph to trend upwards, downwards or neither
periodmin
, periodmax = 0, 0 # vars to enforce trending
direction
= 1 # start in a positive direction, -1 for negative

# DO NOT EDIT BELOW THIS LINE
while(i < maxi)

olddirection
= direction
direction
= Math.sin(sine_index).to_f
direction
= direction < 0 ? direction.floor : direction.ceil

delta
= rand(deltavariance)
yvalue
+= delta * direction

if trend == :positive
yvalue
= periodmin if yvalue < periodmin
periodmin
= yvalue if olddirection < direction
elsif trend == :negative
yvalue
= periodmax if yvalue > periodmax
periodmax
= yvalue if olddirection > direction

end

data
[sine_index] = yvalue
sine_index
+= Math.sin(rand) # Math.sin(rand) will give random numbers from -1..1
i
+= 1
end

code
= <<-CODE
function drawVisualization() {
// Create and populate the data table.
var data = google.visualization.arrayToDataTable([
['x', 'Cats'],
DATASTR

]);

// Create and draw the visualization.
new google.visualization.LineChart(document.getElementById('visualization')).
draw
(data, {curveType: "function",
width
: 500, height: 400,
vAxis
: {maxValue: 10}}
);
}
CODE


datastr
= data.collect{|k,v| "[#{k},#{v}]"}.join(",")
code
= code.gsub('DATASTR', datastr)
puts code