[−][src]Static p5_sys::global::log
pub static log: LogInternalType
Calculates the natural logarithm (the base-e logarithm) of a number. This function expects the n parameter to be a value greater than 0.0. Maps to Math.log().
Examples
function draw() {
background(200);
let maxX = 2.8;
let maxY = 1.5;
// Compute the natural log of a value between 0 and maxX
let xValue = map(mouseX, 0, width, 0, maxX);
let yValue, y;
if (xValue > 0) {
// Cannot take the log of a negative number.
yValue = log(xValue);
y = map(yValue, -maxY, maxY, height, 0);
// Display the calculation occurring.
let legend = 'log(' + nf(xValue, 1, 2) + ')\n= ' + nf(yValue, 1, 3);
stroke(150);
line(mouseX, y, mouseX, height);
fill(0);
text(legend, 5, 15);
noStroke();
ellipse(mouseX, y, 7, 7);
}
// Draw the log(x) curve,
// over the domain of x from 0 to maxX
noFill();
stroke(0);
beginShape();
for (let x = 0; x < width; x++) {
xValue = map(x, 0, width, 0, maxX);
yValue = log(xValue);
y = map(yValue, -maxY, maxY, height, 0);
vertex(x, y);
}
endShape();
line(0, 0, 0, height);
line(0, height / 2, width, height / 2);
}
Parameters
n
number greater than 0