repl.txt (4235B)
1 2 {{alias}}( N, scalar, x, strideX, y, strideY ) 3 Computes the dot product of two single-precision floating-point vectors with 4 extended accumulation. 5 6 The `N`, `strideX`, and `strideY` parameters determine which elements in `x` 7 and `y` are accessed at runtime. 8 9 Indexing is relative to the first index. To introduce an offset, use a typed 10 array view. 11 12 If `N <= 0` the function returns `scalar`. 13 14 Parameters 15 ---------- 16 N: integer 17 Number of indexed elements. 18 19 scalar: number 20 Scalar constant added to dot product. 21 22 x: Float32Array 23 First input array. 24 25 strideX: integer 26 Index increment for `x`. 27 28 y: Float32Array 29 Second input array. 30 31 strideY: integer 32 Index increment for `y`. 33 34 Returns 35 ------- 36 dot: number 37 The dot product of `x` and `y`. 38 39 Examples 40 -------- 41 // Standard usage: 42 > var x = new {{alias:@stdlib/array/float32}}( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] ); 43 > var y = new {{alias:@stdlib/array/float32}}( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] ); 44 > var dot = {{alias}}( x.length, 0.0, x, 1, y, 1 ) 45 -5.0 46 47 // Strides: 48 > x = new {{alias:@stdlib/array/float32}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); 49 > y = new {{alias:@stdlib/array/float32}}( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] ); 50 > var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 ); 51 > dot = {{alias}}( N, 0.0, x, 2, y, -1 ) 52 9.0 53 54 // Using view offsets: 55 > x = new {{alias:@stdlib/array/float32}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); 56 > y = new {{alias:@stdlib/array/float32}}( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] ); 57 > var x1 = new {{alias:@stdlib/array/float32}}( x.buffer, x.BYTES_PER_ELEMENT*1 ); 58 > var y1 = new {{alias:@stdlib/array/float32}}( y.buffer, y.BYTES_PER_ELEMENT*3 ); 59 > N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 ); 60 > dot = {{alias}}( N, 0.0, x1, -2, y1, 1 ) 61 128.0 62 63 {{alias}}.ndarray( N, scalar, x, strideX, offsetX, y, strideY, offsetY ) 64 Computes the dot product of two single-precision floating-point vectors 65 using alternative indexing semantics and with extended accumulation. 66 67 While typed array views mandate a view offset based on the underlying 68 buffer, the `offsetX` and `offsetY` parameters support indexing based on a 69 starting index. 70 71 Parameters 72 ---------- 73 N: integer 74 Number of indexed elements. 75 76 scalar: number 77 Scalar constant added to dot product. 78 79 x: Float32Array 80 First input array. 81 82 strideX: integer 83 Index increment for `x`. 84 85 offsetX: integer 86 Starting index for `x`. 87 88 y: Float32Array 89 Second input array. 90 91 strideY: integer 92 Index increment for `y`. 93 94 offsetY: integer 95 Starting index for `y`. 96 97 Returns 98 ------- 99 dot: number 100 The dot product of `x` and `y`. 101 102 Examples 103 -------- 104 // Standard usage: 105 > var x = new {{alias:@stdlib/array/float32}}( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] ); 106 > var y = new {{alias:@stdlib/array/float32}}( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] ); 107 > var dot = {{alias}}.ndarray( x.length, 0.0, x, 1, 0, y, 1, 0 ) 108 -5.0 109 110 // Strides: 111 > x = new {{alias:@stdlib/array/float32}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); 112 > y = new {{alias:@stdlib/array/float32}}( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] ); 113 > var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 ); 114 > dot = {{alias}}.ndarray( N, 0.0, x, 2, 0, y, 2, 0 ) 115 9.0 116 117 // Using offset indices: 118 > x = new {{alias:@stdlib/array/float32}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); 119 > y = new {{alias:@stdlib/array/float32}}( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] ); 120 > N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 ); 121 > dot = {{alias}}.ndarray( N, 0.0, x, -2, x.length-1, y, 1, 3 ) 122 128.0 123 124 References 125 ---------- 126 - Lawson, Charles L., Richard J. Hanson, Fred T. Krogh, and David Ronald 127 Kincaid. 1979. "Algorithm 539: Basic Linear Algebra Subprograms for Fortran 128 Usage [F1]." *ACM Transactions on Mathematical Software* 5 (3). New York, 129 NY, USA: Association for Computing Machinery: 324–25. 130 doi:10.1145/355841.355848. 131 132 See Also 133 -------- 134