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// Simple sample demonstrating "fixed point" computation with Streams
// See also https://mitpress.mit.edu/sicp/chapter1/node21.html#secprocgeneralmethods
var Stream = Java.type("java.util.stream.Stream");
// generic fixed point procedure
function fixed_point(f, init_guess) {
var tolerance = 0.00001;
function close_enough(v1, v2) Math.abs(v1 - v2) < tolerance;
var prev;
return Stream.iterate(init_guess, f)
.filter(function(x) {
try {
return prev == undefined? false : close_enough(prev, x);
} finally {
prev = x;
}
})
.findFirst()
.get();
}
// solution to x = cos(x)
print(fixed_point(Math.cos, 1.0))
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