105 lines
3.6 KiB
JavaScript
105 lines
3.6 KiB
JavaScript
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// matrices
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// load math.js (using node.js)
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var math = require('../index');
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// create matrices and arrays. a matrix is just a wrapper around an Array,
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// providing some handy utilities.
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console.log('create a matrix');
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var a = math.matrix([1, 4, 9, 16, 25]);
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print(a); // [1, 4, 9, 16, 25]
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var b = math.matrix(math.ones([2, 3]));
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print(b); // [[1, 1, 1], [1, 1, 1]]
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print(b.size()); // [2, 3]
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// the Array data of a Matrix can be retrieved using valueOf()
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var array = a.valueOf();
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print(array); // [1, 4, 9, 16, 25]
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// Matrices can be cloned
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var clone = a.clone();
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print(clone); // [1, 4, 9, 16, 25]
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console.log();
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// perform operations with matrices
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console.log('perform operations');
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print(math.sqrt(a)); // [1, 2, 3, 4, 5]
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var c = [1, 2, 3, 4, 5];
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print(math.factorial(c)); // [1, 2, 6, 24, 120]
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console.log();
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// create and manipulate matrices. Arrays and Matrices can be used mixed.
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console.log('manipulate matrices');
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var d = [[1, 2], [3, 4]];
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print(d); // [[1, 2], [3, 4]]
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var e = math.matrix([[5, 6], [1, 1]]);
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print(e); // [[5, 6], [1, 1]]
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// set a submatrix.
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// Matrix indexes are zero-based.
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e.subset(math.index(1, [0, 1]), [[7, 8]]);
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print(e); // [[5, 6], [7, 8]]
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var f = math.multiply(d, e);
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print(f); // [[19, 22], [43, 50]]
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var g = f.subset(math.index(1, 0));
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print(g); // 43
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console.log();
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// get a sub matrix
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// Matrix indexes are zero-based.
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console.log('get a sub matrix');
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var h = math.diag(math.range(1,4));
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print(h); // [[1, 0, 0], [0, 2, 0], [0, 0, 3]]
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print(h.subset( math.index([1, 2], [1, 2]))); // [[2, 0], [0, 3]]
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var i = math.range(1,6);
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print(i); // [1, 2, 3, 4, 5]
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print(i.subset(math.index(math.range(1,4)))); // [2, 3, 4]
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console.log();
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// resize a multi dimensional matrix
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console.log('resizing a matrix');
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var j = math.matrix();
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var defaultValue = 0;
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j.resize([2, 2, 2], defaultValue);
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print(j); // [[[0, 0], [0, 0]], [[0, 0], [0, 0]]]
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print(j.size()); // [2, 2, 2]
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j.resize([2, 2]);
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print(j); // [[0, 0], [0, 0]]
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print(j.size()); // [2, 2]
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console.log();
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// setting a value outside the matrices range will resize the matrix.
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// new elements will be initialized with zero.
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console.log('set a value outside a matrices range');
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var k = math.matrix();
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k.subset(math.index(2), 6);
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print(k); // [0, 0, 6]
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console.log();
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console.log('set a value outside a matrices range, leaving new entries uninitialized');
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var m = math.matrix();
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defaultValue = math.uninitialized;
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m.subset(math.index(2), 6, defaultValue);
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print(m); // [undefined, undefined, 6]
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console.log();
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// create ranges
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console.log('create ranges');
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print(math.range(1, 6)); // [1, 2, 3, 4, 5]
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print(math.range(0, 18, 3)); // [0, 3, 6, 9, 12, 15]
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print(math.range('2:-1:-3')); // [2, 1, 0, -1, -2]
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print(math.factorial(math.range('1:6'))); // [1, 2, 6, 24, 120]
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console.log();
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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 = 14;
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console.log(math.format(value, precision));
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}
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