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58 lines
1.6 KiB
JavaScript
58 lines
1.6 KiB
JavaScript
// chained operations
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// create an instance of math.js
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var math = require('../index')();
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/**
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* Helper function to output a value in the console. Value will be formatted.
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* @param {*} value
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*/
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function print (value) {
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var precision = 5;
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console.log(math.format(value, precision));
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}
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// create a chained operation using the function select
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// end a chain using done().
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var a = math.select(3)
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.add(4)
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.multiply(2)
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.done();
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print(a); // 14
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// all functions and variables available in the math namespace can be used
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// from a selector
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var b = math.select()
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.pi
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.divide(4)
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.sin()
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.square()
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.done();
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print(b); // 0.5
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// A selector has a few special methods: done, toString, valueOf, get, and set.
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// these are demonstrated in the following examples
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// toString will return a string representation of the selectors value
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var selector = math.select(2).divide(3);
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var str = selector.toString();
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print(str); // "0.6666666666666666"
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// a selector has a .valueOf(), which returns the value hold by the selector.
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// This allows using it in regular operations. The function valueOf() acts the
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// same as function done().
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print(selector + 2); // 2.66667
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print(math.square(selector)); // 0.44444
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// the function subset can be used to get or replace sub matrices
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var array = [[1, 2], [3, 4]];
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var v = math.select(array)
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.subset(math.index(1, 0));
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print(v); // 3
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var m = math.select(array)
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.subset(math.index(0, 0), 8)
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.multiply(3)
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.done();
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print(m); // [[24, 6], [9, 12]]
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