iterMap3
Create an iterator which invokes a ternary function accepting numeric arguments for each iterated value.
Usage
var iterMap3 = require( '@stdlib/math/iter/tools/map3' );
iterMap3( iter0, iter1, iter2, fcn[, options] )
Returns an iterator which invokes a ternary function
accepting numeric arguments for each iterated value.
var array2iterator = require( '@stdlib/array/to-iterator' );
var clamp = require( '@stdlib/math/base/special/clamp' );
var x = array2iterator( [ 1.0, -2.0, 3.0, 14.0 ] );
var min = array2iterator( [ 1.0, 0.0, -1.0, 1.0 ] );
var max = array2iterator( [ 10.0, 10.0, 2.0, 10.0 ] );
var it = iterMap3( x, min, max, clamp );
// returns <Object>
var r = it.next().value;
// returns 1.0
r = it.next().value;
// returns 0.0
r = it.next().value;
// returns 2.0
// ...
The returned iterator protocol-compliant object has the following properties:
- next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a
value
property and adone
property having aboolean
value indicating whether the iterator is finished. - return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.
The invoked function
is provided three arguments:
x
: iterated value from first input iterator.y
: iterated value from second input iterator.z
: iterated value from third input iterator.
var array2iterator = require( '@stdlib/array/to-iterator' );
function fcn( x, y, z ) {
return x + y + z + 10;
}
var it1 = array2iterator( [ 1, 2, 3, 4 ] );
var it2 = array2iterator( [ 1, 2, 3, 4 ] );
var it3 = array2iterator( [ 1, 2, 3, 4 ] );
var it = iterMap3( it1, it2, it3, fcn );
// returns <Object>
var r = it.next().value;
// returns 13
r = it.next().value;
// returns 16
r = it.next().value;
// returns 19
// ...
The function supports the following options
:
- invalid: return value when an input iterator yields a non-numeric value. Default:
NaN
.
By default, the function returns an iterator which returns NaN
when an input iterator yields a non-numeric value. To specify a different return value, set the invalid
option.
var array2iterator = require( '@stdlib/array/to-iterator' );
var clamp = require( '@stdlib/math/base/special/clamp' );
var it1 = array2iterator( [ '1.0', '2.0', '3.0' ] );
var it2 = array2iterator( [ 0.0, 0.0, 0.0 ] );
var it3 = array2iterator( [ 10.0, 10.0, 10.0 ] );
var opts = {
'invalid': null
};
var it = iterMap3( it1, it2, it3, clamp, opts );
// returns <Object>
var v = it.next().value;
// returns null
v = it.next().value;
// returns null
// ...
If provided a numeric value as an iterator
argument, the value is broadcast as an infinite iterator which always returns the provided value.
var array2iterator = require( '@stdlib/array/to-iterator' );
var clamp = require( '@stdlib/math/base/special/clamp' );
var x = array2iterator( [ -1.0, 20.0 ] );
var it = iterMap3( x, 0.0, 10.0, clamp );
// returns <Object>
var v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 10.0
var bool = it.next().done;
// returns true
Notes
- If an iterated value is non-numeric (including
NaN
), the returned iterator returnsNaN
. If non-numeric iterated values are possible, you are advised to provide aniterator
which type checks and handles non-numeric values accordingly. - The length of the returned iterator is equal to the length of the shortest provided iterator. In other words, the returned iterator ends once one of the provided iterators ends.
- If an environment supports
Symbol.iterator
and a provided iterator is iterable, the returned iterator is iterable.
Examples
var uniform = require( '@stdlib/random/iter/uniform' );
var clamp = require( '@stdlib/math/base/special/clamp' );
var iterMap3 = require( '@stdlib/math/iter/tools/map3' );
// Create seeded iterators for generating pseudorandom numbers:
var x = uniform( 0.0, 10.0, {
'seed': 1234,
'iter': 10
});
var min = uniform( 0.0, 1.0, {
'seed': 4567,
'iter': 10
});
var max = uniform( 9.0, 10.0, {
'seed': 7895,
'iter': 10
});
// Create an iterator which consumes the pseudorandom number iterators:
var it = iterMap3( x, min, max, clamp );
// Perform manual iteration...
var r;
while ( true ) {
r = it.next();
if ( r.done ) {
break;
}
console.log( r.value );
}