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Vector products: Difference between revisions
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<-267.0, 204.0, -3.0></pre>
=={{header|JavaScript}}==
The <code>dotProduct()</code> function is generic and will create a dot product of any set of vectors provided they are all the same dimension.
The <code>crossProduct()</code> function expects two 3D vectors.
<lang javascript>function dotProduct() {
var len = arguments[0] && arguments[0].length;
var argsLen = arguments.length;
var i, j = len;
var prod, sum = 0;
// If no arguments supplied, return undefined
if (!len) {
return;
}
// If all vectors not same length, return undefined
i = argsLen;
while (i--) {
if (arguments[i].length != len) {
return; // return undefined
}
}
// Sum terms
while (j--) {
i = argsLen;
prod = 1;
while (i--) {
prod *= arguments[i][j];
}
sum += prod;
}
return sum;
}
function crossProduct(a, b) {
// Check lengths
if (a.length != 3 || b.length != 3) {
return;
}
return [a[1]*b[2] - a[2]*b[1],
a[2]*b[0] - a[0]*b[2],
a[0]*b[1] - a[1]*b[0]];
}
function scalarTripleProduct(a, b, c) {
return dotProduct(a, crossProduct(b, c));
}
function vectorTripleProduct(a, b, c) {
return crossProduct(a, crossProduct(b, c));
}
// Run tests
(function () {
var a = [3, 4, 5];
var b = [4, 3, 5];
var c = [-5, -12, -13];
alert(
'A . B: ' + dotProduct(a, b) +
'\n' +
'A x B: ' + crossProduct(a, b) +
'\n' +
'A . (B x C): ' + scalarTripleProduct(a, b, c) +
'\n' +
'A x (B x C): ' + vectorTripleProduct(a, b, c)
);
}());
</lang>
Output:
<pre>
A . B: 49
A x B: 5,5,-7
A . (B x C): 6
A x (B x C): -267,204,-3
</pre>
=={{header|Liberty BASIC}}==
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