Create a double-precision floating-point matrix (i.e., a two-dimensional ndarray).

var Float64Matrix = require( '@stdlib/ndarray/matrix/float64' );

Returns a two-dimensional double-precision floating-point ndarray.

var getShape = require( '@stdlib/ndarray/shape' );

var arr = new Float64Matrix();
// returns <ndarray>

var len = getShape( arr );
// returns [ 0, 0 ]

The function accepts the following options:

• order: specifies whether an ndarray is 'row-major' (C-style) or 'column-major' (Fortran-style). Default: 'row-major'.
• mode: specifies how to handle indices which exceed array dimensions (see ndarray). Default: 'throw'.
• submode: a mode array which specifies for each dimension how to handle subscripts which exceed array dimensions (see ndarray). If provided fewer modes than dimensions, an ndarray) instance recycles modes using modulo arithmetic. Default: [ options.mode ].
• readonly: boolean indicating whether an array should be read-only. Default: false.

Returns a two-dimensional double-precision floating-point ndarray having a specified shape.

var getShape = require( '@stdlib/ndarray/shape' );

var arr = new Float64Matrix( [ 3, 3 ] );
// returns <ndarray>

var sh = getShape( arr );
// returns [ 3, 3 ]

The function accepts the following arguments:

• shape: array shape. Must contain exactly two elements.
• options: function options. See above.

Returns a two-dimensional double-precision floating-point ndarray having a specified shape.

var getShape = require( '@stdlib/ndarray/shape' );

var arr = new Float64Matrix( 3, 3 );
// returns <ndarray>

var sh = getShape( arr );
// returns [ 3, 3 ]

The function accepts the following arguments:

• M: number of rows.
• N: number of columns.
• options: function options. See above.

Creates a two-dimensional double-precision floating-point ndarray from an array-like object or iterable.

var getShape = require( '@stdlib/ndarray/shape' );

var arr = new Float64Matrix( [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] );
// returns <ndarray>

var sh = getShape( arr );
// returns [ 2, 2 ]

The function accepts the following arguments:

• obj: array-like object or iterable from which to generate an ndarray. If an array-like object, the value must be a nested array (i.e., an array-like object of array-like objects), where each nested array must have the same number of elements. If an iterable, the iterable must return array-like objects, each of which must have the same number of elements.
• options: function options. See above.

Returns a two-dimensional double-precision floating-point ndarray view of an ArrayBuffer.

var ArrayBuffer = require( '@stdlib/array/buffer' );
var getShape = require( '@stdlib/ndarray/shape' );

var buf = new ArrayBuffer( 64 );

var arr1 = new Float64Matrix( buf );
// returns <ndarray>

var sh1 = getShape( arr1 );
// returns [ 1, 8 ]

var arr2 = new Float64Matrix( buf, 16 );
// returns <ndarray>

var sh2 = getShape( arr2 );
// returns [ 1, 6 ]

var arr3 = new Float64Matrix( buf, 16, [ 2, 1 ] );
// returns <ndarray>

var sh3 = getShape( arr3 );
// returns [ 2, 1 ]

The function accepts the following arguments:

• buffer: underlying ArrayBuffer.
• byteOffset: integer byte offset specifying the location of the first indexed element. Default: 0.
• shape: array shape. Must contain exactly two elements.
• options: function options. See above.

Returns a two-dimensional double-precision floating-point ndarray view of an ArrayBuffer.

var ArrayBuffer = require( '@stdlib/array/buffer' );
var getShape = require( '@stdlib/ndarray/shape' );

var buf = new ArrayBuffer( 64 );

var arr = new Float64Matrix( buf, 16, 2, 1 );
// returns <ndarray>

var sh = getShape( arr );
// returns [ 2, 1 ]

The function accepts the following arguments:

• buffer: underlying ArrayBuffer.
• byteOffset: integer byte offset specifying the location of the first indexed element. Default: 0.
• M: number of rows.
• N: number of columns.
• options: function options. See above.

• Nested arrays are flattened in lexicographic order, such that, for an input nested array obj, obj[i][j] corresponds to the element mat.get(i, j) in the returned two-dimensional ndarray. In other words, an input nested array is assumed to be comprised of rows. Similarly, if obj is an iterable, each array returned by the iterable is assumed to correspond to a matrix row.
• If provided an ArrayBuffer without corresponding shape arguments, the leading dimension of the returned ndarray always has a size of one.

var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var sum = require( '@stdlib/blas/ext/sum' );
var map = require( '@stdlib/ndarray/map' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var Float64Matrix = require( '@stdlib/ndarray/matrix/float64' );

// Create a matrix containing random values:
var x = new Float64Matrix([
    discreteUniform( 10, 0, 100 ),
    discreteUniform( 10, 0, 20 )
]);

// Compute the sum along the columns:
var v = sum( x, {
    'dims': [ -1 ]
});
console.log( ndarray2array( v ) );

// Define a function which applies a threshold to individual values:
function threshold( v ) {
    return ( v > 10 ) ? v : 0;
}

// Apply threshold:
var y = map( x, threshold );

// Recompute the sum along the columns:
v = sum( y, {
    'dims': [ -1 ]
});
console.log( ndarray2array( v ) );

• @stdlib/ndarray/matrix/float32: create a single-precision floating-point matrix (i.e., a two-dimensional ndarray).
• @stdlib/ndarray/matrix/int32: create a 32-bit signed integer matrix (i.e., a two-dimensional ndarray).
• @stdlib/ndarray/matrix/complex128: create a double-precision complex floating-point matrix (i.e., a two-dimensional ndarray).
• @stdlib/ndarray/matrix/complex64: create a single-precision complex floating-point matrix (i.e., a two-dimensional ndarray).
• @stdlib/ndarray/matrix/ctor: create a matrix (i.e., a two-dimensional ndarray).
• @stdlib/ndarray/vector/float64: create a double-precision floating-point vector (i.e., a one-dimensional ndarray).
• @stdlib/ndarray/ctor: multidimensional array constructor.